fix: noconfirm auto-selects first AUR match

local/recipes/dev/bison/source/examples/c/README.md

@@ -0,0 +1,99 @@
+# Examples in C
+
+This directory contains simple examples of Bison grammar files in C.
+
+Some of them come from the documentation, which should be installed together
+with Bison.  The URLs are provided for convenience.
+
+## rpcalc - Reverse Polish Notation Calculator
+The first example is that of a simple double-precision Reverse Polish
+Notation calculator (a calculator using postfix operators). This example
+provides a good starting point, since operator precedence is not an issue.
+
+Extracted from the documentation: [Reverse Polish Notation
+Calculator](https://www.gnu.org/software/bison/manual/html_node/RPN-Calc.html).
+
+## calc - Simple Calculator
+This example is slightly more complex than rpcalc: it features infix
+operators (`1 + 2`, instead of `1 2 +` in rpcalc), but it does so using a
+unambiguous grammar of the arithmetic instead of using precedence
+directives (%left, etc.).
+
+## mfcalc - Multi-Function Calculator
+A more complete C example: a multi-function calculator.  More complex than
+the previous example.  Using precedence directives to support infix
+operators.
+
+Extracted from the documentation: [Multi-Function Calculator:
+mfcalc](https://www.gnu.org/software/bison/manual/html_node/Multi_002dfunction-Calc.html).
+
+## lexcalc - calculator with Flex and Bison
+The calculator with precedence directives and location tracking.  It uses
+Flex to generate the scanner.
+
+## reccalc - recursive calculator with Flex and Bison
+This example builds on top of the previous one to provide a reentrant
+parser.  Such parsers can be called concurrently in different threads, or
+even recursively.  To demonstrate this feature, expressions in parentheses
+are tokenized as strings, and then recursively parsed from the parser.  So
+`(((1)+(2))*((3)+(4)))` uses eight parsers, with a depth of four.
+
+## pushcalc - calculator implemented with a push parser
+All the previous examples are so called "pull parsers": the user invokes the
+parser once, which repeatedly calls the scanner until the input is drained.
+
+This example demonstrates the "push parsers": the user calls the scanner to
+fetch the next token, passes it to the parser, and repeats the operation
+until the input is drained.
+
+This example is a straightforward conversion of the 'calc' example to the
+push-parser model.
+
+## bistromathic - all the bells and whistles
+This example demonstrates best practices when using Bison.
+- Its hand-written scanner tracks locations.
+- Its interface is pure.
+- It uses %params to pass user information to the parser and scanner.
+- Its scanner uses the `error` token to signal lexical errors and enter
+  error recovery.
+- Its interface is "incremental", well suited for interaction: it uses the
+  push-parser API to feed the parser with the incoming tokens.
+- It features an interactive command line with completion based on the
+  parser state, based on `yyexpected_tokens`.
+- It uses Bison's standard catalog for internationalization of generated
+  messages.
+- It uses a custom syntax error with location, lookahead correction and
+  token internationalization.
+- Error messages quote the source with squiggles that underline the error:
+```
+> 123 456
+1.5-7: syntax error: expected end of file or + or - or * or / or ^ before number
+    1 | 123 456
+      |     ^~~
+```
+- It supports debug traces with semantic values.
+- It uses named references instead of the traditional $1, $2, etc.
+
+<!---
+
+Local Variables:
+fill-column: 76
+ispell-dictionary: "american"
+End:
+
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
+
+This file is part of GNU bison, the GNU Compiler Compiler.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts.  A copy of the license is included in the "GNU Free
+Documentation License" file as part of this distribution.
+
+LocalWords:  mfcalc calc parsers yy rpcalc lexcalc redux reccalc ispell
+LocalWords:  reentrant tokenized american postfix pushcalc bistromathic
+LocalWords:  lookahead
+
+-->

local/recipes/dev/bison/source/examples/c/bistromathic/Makefile

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+# This Makefile is designed to be simple and readable.  It does not
+# aim at portability.  It requires GNU Make.
+
+BASE = bistromathic
+BISON = bison
+
+# We need to find the headers and libs for readline (and possibly intl).
+# You probably need to customize this for your own environment.
+CPPFLAGS = -I/opt/local/include
+LDFLAGS = -L/opt/local/lib
+
+# Find the translation catalog for Bison's generated messagess.
+BISON_LOCALEDIR = $(shell $(BISON) $(BISON_FLAGS) --print-localedir)
+CPPFLAGS += -DENABLE_NLS -DBISON_LOCALEDIR='"$(BISON_LOCALEDIR)"'
+
+LIBS = -lreadline -lm # In some environments, -lintl is needed.
+
+all: $(BASE)
+
+%.c %.h %.html %.xml %.gv: %.y
+	$(BISON) $(BISONFLAGS) --header --html --graph -o $*.c $<
+
+$(BASE): parse.o
+	$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS)
+
+run: $(BASE)
+	@echo "Type bistromathic expressions.  Quit with ctrl-d."
+	./$<
+
+CLEANFILES =						\
+  $(BASE) *.o						\
+  parse.[ch] parse.output parse.xml parse.html parse.gv
+
+clean:
+	rm -f $(CLEANFILES)

local/recipes/dev/bison/source/examples/c/bistromathic/README.md

@@ -0,0 +1,49 @@
+# bistromathic - all the bells and whistles
+This example demonstrates best practices when using Bison.
+- Its hand-written scanner tracks locations.
+- Its interface is pure.
+- It uses %params to pass user information to the parser and scanner.
+- Its scanner uses the `error` token to signal lexical errors and enter
+  error recovery.
+- Its interface is "incremental", well suited for interaction: it uses the
+  push-parser API to feed the parser with the incoming tokens.
+- It features an interactive command line with completion based on the
+  parser state, based on `yyexpected_tokens`.
+- It uses Bison's standard catalog for internationalization of generated
+  messages.
+- It uses a custom syntax error with location, lookahead correction and
+  token internationalization.
+- Error messages quote the source with squiggles that underline the error:
+```
+> 123 456
+1.5-7: syntax error: expected end of file or + or - or * or / or ^ before number
+    1 | 123 456
+      |     ^~~
+```
+- It supports debug traces with semantic values.
+- It uses named references instead of the traditional $1, $2, etc.
+
+To customize the interaction with bistromathic, see the GNU Readline user
+manual (see `info rluserman`).
+
+<!---
+Local Variables:
+fill-column: 76
+ispell-dictionary: "american"
+End:
+
+Copyright (C) 2020-2021 Free Software Foundation, Inc.
+
+This file is part of Bison, the GNU Compiler Compiler.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts.  A copy of the license is included in the "GNU Free
+Documentation License" file as part of this distribution.
+
+LocalWords:  bistromathic yyexpected lookahead ispell american
+LocalWords:  MERCHANTABILITY
+
+--->

local/recipes/dev/bison/source/examples/c/bistromathic/bistromathic.test

@@ -0,0 +1,368 @@
+#! /bin/sh
+
+# Copyright (C) 2020-2021 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# Users may customize the behavior of readline, which might break our
+# expected results.
+INPUTRC=/dev/null
+export INPUTRC
+
+# Beware of portability issues of readline when not feeding it from a
+# terminal.
+#
+# With recent versions of GNU Readline, input "1+2*3\n" gives
+# "> 1+2*3\n7\n> \n"
+#
+# macOS' version does not display the prompt and does not repeat stdin
+# on stdout, so input "1+2*3\n" gives "7\n" as output.  Let's try to
+# cope with this.
+#
+# On OpenBSD 6.5 the prompt is displayed, but the input is not
+# repeated (!).  So input "1+2*3\n" gives "> 7\n> \n" as output.
+#
+# On AIX, you get some escaping sequence before the prompt:
+# "<ESC>[?1034h> 1+2*3".  It appears to pass the terminfo capability
+# "smm", to put the terminal in "meta mode": as if the user had hit
+# META.
+
+echo >perfect '> 0
+0
+> '
+
+echo >ok '0'
+echo '0' | prog >effective
+
+echo "checking for readline output..."
+if diff perfect effective; then
+    # Alles ist gut.
+    strip_prompt=false
+elif diff ok effective; then
+    strip_prompt=true
+else
+    skip "this is not the GNU Readline we expect"
+fi
+
+
+cat >input <<EOF
+1+2*3
+EOF
+run 0 '> 1+2*3
+7
+> '
+
+cat >input <<EOF
+(1+2) * 3
+EOF
+run 0  '> (1+2) * 3
+9
+> '
+run -noerr 0 '> (1+2) * 3
+9
+> ' -p
+
+cat >input <<EOF
+a = 256
+sqrt (a)
+EOF
+run 0 '> a = 256
+256
+> sqrt (a)
+16
+> '
+
+cat >input <<EOF
+a = .16
+b = 10 ^ 2
+sqrt (a * b)
+EOF
+run 0 '> a = .16
+0.16
+> b = 10 ^ 2
+100
+> sqrt (a * b)
+4
+> '
+
+cat >input <<EOF
+*
+EOF
+run 0 '> *
+> ''
+err: 1.1: syntax error: expected end of file or - or ( or exit or number or function etc., before *
+err:     1 | *
+err:       | ^'
+
+# Underline long errors.
+cat >input <<EOF
+123 123456
+EOF
+run 0 '> 123 123456
+> ''
+err: 1.5-10: syntax error: expected end of file or + or - or * or / or ^ before number
+err:     1 | 123 123456
+err:       |     ^~~~~~'
+
+cat >input <<EOF
+1 + 2 * * 3
+EOF
+run 0 '> 1 + 2 * * 3
+> ''
+err: 1.9: syntax error: expected - or ( or number or function or variable before *
+err:     1 | 1 + 2 * * 3
+err:       |         ^'
+
+cat >input <<EOF
+1 / 0
+EOF
+run 0 '> 1 / 0
+> ''
+err: 1.1-5: error: division by zero'
+
+
+## ---------------- ##
+## Error recovery.  ##
+## ---------------- ##
+
+cat >input <<EOF
+((1 ++ 2) ** 3)
+(1 ++ 2) + (3 ** 4)
+EOF
+run 0 '> ((1 ++ 2) ** 3)
+666
+> (1 ++ 2) + (3 ** 4)
+1332
+> ''
+err: 1.6: syntax error: expected - or ( or number or function or variable before +
+err:     1 | ((1 ++ 2) ** 3)
+err:       |      ^
+err: 2.5: syntax error: expected - or ( or number or function or variable before +
+err:     2 | (1 ++ 2) + (3 ** 4)
+err:       |     ^
+err: 2.16: syntax error: expected - or ( or number or function or variable before *
+err:     2 | (1 ++ 2) + (3 ** 4)
+err:       |                ^'
+
+# The rule "( error )" should work even if there are no tokens between "(" and ")".
+cat >input <<EOF
+()
+EOF
+run 0 '> ()
+666
+> ''
+err: 1.2: syntax error: expected - or ( or number or function or variable before )
+err:     1 | ()
+err:       |  ^'
+
+
+cat >input <<EOF
+100% + 10
+EOF
+run 0 '> 100% + 10
+> ''
+err: 1.4: syntax error: invalid character: %'
+
+# Traces.  This allows to check the location of the error.  If we
+# forget to map YYerror to YYUNDEF, error recovery enters an endless
+# loop with this input.
+cat >input <<EOF
+(+_)
+EOF
+run 0 '> (+_)
+666
+> ''
+err: Starting parse
+err: Entering state 0
+err: Stack now 0
+err: Reading a token
+err: Next token is token ( (1.1: )
+err: Shifting token ( (1.1: )
+err: Entering state 2
+err: Stack now 0 2
+err: Return for a new token:
+err: Reading a token
+err: Next token is token + (1.2: )
+err: LAC: initial context established for +
+err: LAC: checking lookahead +: Err
+err: LAC: checking lookahead end of file: Err
+err: LAC: checking lookahead +: Err
+err: LAC: checking lookahead -: S1
+err: LAC: checking lookahead *: Err
+err: LAC: checking lookahead /: Err
+err: LAC: checking lookahead ^: Err
+err: LAC: checking lookahead (: S2
+err: LAC: checking lookahead ): Err
+err: LAC: checking lookahead =: Err
+err: LAC: checking lookahead exit: Err
+err: LAC: checking lookahead number: S4
+err: LAC: checking lookahead function: S5
+err: LAC: checking lookahead variable: S6
+err: LAC: checking lookahead NEG: Err
+err: 1.2: syntax error: expected - or ( or number or function or variable before +
+err:     1 | (+_)
+err:       |  ^
+err: LAC: initial context discarded due to error recovery
+err: Shifting token error (1.2: )
+err: Entering state 10
+err: Stack now 0 2 10
+err: Next token is token + (1.2: )
+err: LAC: initial context established for +
+err: LAC: checking lookahead +: Err
+err: Error: discarding token + (1.2: )
+err: Error: popping token error (1.2: )
+err: Stack now 0 2
+err: LAC: initial context discarded due to error recovery
+err: Shifting token error (1.2: )
+err: Entering state 10
+err: Stack now 0 2 10
+err: Return for a new token:
+err: 1.3: syntax error: invalid character: _
+err: Reading a token
+err: Error: popping token error (1.2: )
+err: Stack now 0 2
+err: Shifting token error (1.2-3: )
+err: Entering state 10
+err: Stack now 0 2 10
+err: Next token is token invalid token (1.3: )
+err: LAC: initial context established for invalid token
+err: LAC: checking lookahead invalid token: Always Err
+err: Error: discarding token invalid token (1.3: )
+err: Error: popping token error (1.2-3: )
+err: Stack now 0 2
+err: LAC: initial context discarded due to error recovery
+err: Shifting token error (1.2-3: )
+err: Entering state 10
+err: Stack now 0 2 10
+err: Return for a new token:
+err: Reading a token
+err: Next token is token ) (1.4: )
+err: Shifting token ) (1.4: )
+err: Entering state 20
+err: Stack now 0 2 10 20
+err: Reducing stack by rule XX (line XXX):
+err:    $1 = token ( (1.1: )
+err:    $2 = token error (1.2-3: )
+err:    $3 = token ) (1.4: )
+err: -> $$ = nterm exp (1.1-4: 666)
+err: Entering state 8
+err: Stack now 0 8
+err: Return for a new token:
+err: Reading a token
+err: Now at end of input.
+err: LAC: initial context established for end of file
+err: LAC: checking lookahead end of file: R2 G7 S14
+err: Reducing stack by rule XX (line XXX):
+err:    $1 = nterm exp (1.1-4: 666)
+err: -> $$ = nterm input (1.1-4: )
+err: Entering state 7
+err: Stack now 0 7
+err: Now at end of input.
+err: Shifting token end of file (1.5: )
+err: LAC: initial context discarded due to shift
+err: Entering state 14
+err: Stack now 0 7 14
+err: Stack now 0 7 14
+err: Cleanup: popping token end of file (1.5: )
+err: Cleanup: popping nterm input (1.1-4: )' -p
+
+
+
+## ------------ ##
+## Completion.  ##
+## ------------ ##
+
+# From now on, the differences between versions of GNU Readline are
+# too painful to try to cope with.
+if $strip_prompt; then
+  echo "SKIP: this is not the GNU Readline we expect"
+  exit $status
+fi
+
+# On Windows10/MSYS2 the ^G coming from <tab> completion is not
+# emitted the same way
+# (https://lists.gnu.org/r/bug-bison/2020-05/msg00076.html).
+echo "checking for kernel name... $(uname -s)"
+case $(uname -s) in
+  (MSYS*)
+    echo "SKIP: this is Windows/MSYS"
+    exit $status
+    ;;
+esac
+
+
+# Check completion after an operator.
+sed -e 's/\\t/	/g' >input <<EOF
+(1+\t\t
+EOF
+# Nuke the possible trailing white spaces in the effective output.
+# This is to cope with some readlines that pad all the suggestions
+# with white spaces (for alignment), including the last one on a line.
+#
+# See for instance <https://trac.macports.org/ticket/59927#comment:48>
+# and its test-suite.log:
+# <https://trac.macports.org/attachment/ticket/59927/bison-3.7.6-test-10.13.test-suite.log>
+run -t 0 '> (1+
+(       -       atan    cos     exp     ln      number  sin     sqrt
+> (1+
+>
+err: 1.4: syntax error: expected - or ( or number or function or variable before end of file
+err:     1 | (1+
+err:       |    ^'
+
+# Check the completion of a word.
+sed -e 's/\\t/	/g' >input <<EOF
+(at\t\t
+EOF
+run 0 '> (atan ( ''
+> ''
+err: 1.9: syntax error: expected - or ( or number or function or variable before end of file
+err:     1 | (atan ( ''
+err:       |         ^'
+
+# Check the completion at the very beginning.
+sed -e 's/\\t/	/g' >input <<EOF
+e\t\t
+EOF
+run -n 0 '> e
+end of file  exit         exp          ''
+> e
+0
+> ''
+err: '
+
+# Check that completion prints valid locations even when there is an error.
+sed -e 's/\\t/	/g' >input <<EOF
+1++\t
+EOF
+run -n 0 '> 1++ ''
+> ''
+err: 1.3: syntax error: expected - or ( or number or function or variable before +
+err:     1 | 1++ ''
+err:       |   ^
+'
+
+# And even when the error was recovered from.
+sed -e 's/\\t/	/g' >input <<EOF
+(1++2) + 3 +\t\t
+EOF
+run -n 0 '> (1++2) + 3 +  ''
+> ''
+err: 1.4: syntax error: expected - or ( or number or function or variable before +
+err:     1 | (1++2) + 3 +  ''
+err:       |    ^
+err: 1.15: syntax error: expected - or ( or number or function or variable before end of file
+err:     1 | (1++2) + 3 +  ''
+err:       |               ^
+'

local/recipes/dev/bison/source/examples/c/bistromathic/local.mk

@@ -0,0 +1,41 @@
+## Copyright (C) 2020-2021 Free Software Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+bistromathicdir = $(docdir)/%D%
+
+## --------------- ##
+## Bistromathics.  ##
+## --------------- ##
+
+%D%/parse.c: $(dependencies)
+
+if ENABLE_BISTROMATHIC
+  check_PROGRAMS += %D%/bistromathic
+  TESTS += %D%/bistromathic.test
+  nodist_%C%_bistromathic_SOURCES = %D%/parse.y
+
+  # Don't use gnulib's system headers.
+  %C%_bistromathic_CPPFLAGS =			\
+    -DBISON_LOCALEDIR='"$(localdir)"'		\
+    -DLOCALEDIR='"$(localdir)"'			\
+    -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+  %C%_bistromathic_CFLAGS = $(TEST_CFLAGS)
+  %C%_bistromathic_LDADD = -lm $(LIBREADLINE) $(LIBINTL)
+endif
+
+EXTRA_DIST += %D%/bistromathic.test
+dist_bistromathic_DATA = %D%/parse.y %D%/Makefile %D%/README.md
+CLEANFILES += %D%/parse.[ch] %D%/parse.output
+CLEANDIRS += %D%/*.dSYM

local/recipes/dev/bison/source/examples/c/bistromathic/parse.y

@@ -0,0 +1,695 @@
+/* Parser and scanner for bistromathic.   -*- C -*-
+
+   Copyright (C) 2019-2021 Free Software Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+%require "3.7"
+
+// Emitted on top of the implementation file.
+%code top {
+  #include <ctype.h>  // isdigit
+  #include <locale.h> // LC_ALL
+  #include <math.h>   // cos, sin, etc.
+  #include <stdarg.h> // va_start
+  #include <stdio.h>  // printf
+  #include <stdlib.h> // calloc
+  #include <string.h> // strcmp
+
+  #include <readline/readline.h>
+  #include <readline/history.h>
+
+  #if defined ENABLE_NLS && ENABLE_NLS
+  // Unable the translation of Bison's generated messages.
+  # define YYENABLE_NLS 1
+  # include <libintl.h>
+  // Unless specified otherwise, we expect bistromathic's own
+  // catalog to be installed in the same tree as Bison's catalog.
+  # ifndef LOCALEDIR
+  #  define LOCALEDIR BISON_LOCALEDIR
+  # endif
+  #endif
+}
+
+// Emitted in the header file, before the definition of YYSTYPE.
+%code requires {
+  // Function type.
+  typedef double (func_t) (double);
+
+  // Data type for links in the chain of symbols.
+  typedef struct symrec symrec;
+  struct symrec
+  {
+    char *name;  // name of symbol
+    int type;    // type of symbol: either VAR or FUN
+    union
+    {
+      double var;    // value of a VAR
+      func_t *fun;   // value of a FUN
+    } value;
+    symrec *next;  // link field
+  };
+
+  symrec *putsym (char const *name, int sym_type);
+  symrec *getsym (char const *name);
+
+  // Exchanging information with the parser.
+  typedef struct
+  {
+    // Whether to not emit error messages.
+    int silent;
+    // The current input line.
+    const char *line;
+  } user_context;
+}
+
+// Emitted in the header file, after the definition of YYSTYPE.
+%code provides {
+# ifndef __attribute__
+#  ifndef __GNUC__
+#   define __attribute__(Spec) /* empty */
+#  endif
+# endif
+
+  yytoken_kind_t
+  yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc,
+         const user_context *uctx);
+  void yyerror (const YYLTYPE *loc, const user_context *uctx,
+                char const *format, ...)
+    __attribute__ ((__format__ (__printf__, 3, 4)));
+}
+
+// Emitted in the implementation file.
+%code {
+  // Print *LOC on OUT.
+  static void location_print (FILE *out, YYLTYPE const * const loc);
+  #define YYLOCATION_PRINT location_print
+
+  #if defined ENABLE_NLS && ENABLE_NLS
+  # define _(Msgid)  gettext (Msgid)
+  #else
+  # define _(Msgid)  (Msgid)
+  #endif
+
+  // Whether to quit.
+  int done = 0;
+}
+
+// Include the header in the implementation rather than duplicating it.
+%define api.header.include {"parse.h"}
+
+// Don't share global variables between the scanner and the parser.
+%define api.pure full
+
+// Generate a push parser.
+%define api.push-pull push
+
+// To avoid name clashes (e.g., with C's EOF) prefix token definitions
+// with TOK_ (e.g., TOK_EOF).
+%define api.token.prefix {TOK_}
+
+// Customized syntax error messages (see yyreport_syntax_error)...
+%define parse.error custom
+
+// ... with locations...
+%locations
+
+// ... and accurate list of expected tokens.
+%define parse.lac full
+
+// Generate the parser description file (calc.output).
+%verbose
+
+// User information exchanged with the parser and scanner.
+%param {const user_context *uctx}
+
+// Generate YYSTYPE from the types assigned to symbols.
+%define api.value.type union
+%token
+    PLUS   "+"
+    MINUS  "-"
+    STAR   "*"
+    SLASH  "/"
+    CARET  "^"
+    LPAREN "("
+    RPAREN ")"
+    EQUAL  "="
+    EXIT   "exit"
+  <double>
+    NUM _("number")
+  <symrec*>
+    FUN _("function")
+    VAR _("variable")
+
+%nterm <double>  exp
+
+// Enable run-time traces (yydebug).
+%define parse.trace
+
+// Formatting semantic values in debug traces.
+%printer { fprintf (yyo, "%s", $$->name); } VAR;
+%printer { fprintf (yyo, "%s()", $$->name); } FUN;
+%printer { fprintf (yyo, "%g", $$); } <double>;
+
+
+// Precedence (from lowest to highest) and associativity.
+%precedence "="
+%left "+" "-"
+%left "*" "/"
+%precedence NEG // negation--unary minus
+%right "^"      // exponentiation
+
+%% // The grammar follows.
+input:
+  %empty
+| exp     { printf ("%.10g\n", $exp); }
+| "exit"  { done = 1; }
+;
+
+exp:
+  NUM
+| VAR               { $$ = $VAR->value.var; }
+| VAR "=" exp       { $$ = $3; $VAR->value.var = $3; }
+| FUN "(" exp ")"   { $$ = $FUN->value.fun ($3); }
+| exp[l] "+" exp[r] { $$ = $l + $r; }
+| exp[l] "-" exp[r] { $$ = $l - $r; }
+| exp[l] "*" exp[r] { $$ = $l * $r; }
+| exp[l] "/" exp[r]
+  {
+    if ($r == 0)
+      {
+        yyerror (&@$, uctx, _("error: division by zero"));
+        YYERROR;
+      }
+    else
+      $$ = $l / $r;
+  }
+| "-" exp  %prec NEG { $$ = -$2; }
+| exp[l] "^" exp[r]  { $$ = pow ($l, $r); }
+| "(" exp ")"        { $$ = $2; }
+| "(" error ")"      { $$ = 666; }
+;
+
+// End of grammar.
+%%
+
+/*------------.
+| Functions.  |
+`------------*/
+
+struct init
+{
+  char const *name;
+  func_t *fun;
+};
+
+static struct init const funs[] =
+{
+  { "atan", atan },
+  { "cos",  cos  },
+  { "exp",  exp  },
+  { "ln",   log  },
+  { "sin",  sin  },
+  { "sqrt", sqrt },
+  { 0, 0 },
+};
+
+// The symbol table: a chain of 'struct symrec'.
+static symrec *sym_table;
+
+// Put functions in table.
+static void
+init_table (void)
+{
+  for (int i = 0; funs[i].name; i++)
+    {
+      symrec *ptr = putsym (funs[i].name, TOK_FUN);
+      ptr->value.fun = funs[i].fun;
+    }
+}
+
+symrec *
+putsym (char const *name, int sym_type)
+{
+  symrec *res = (symrec *) malloc (sizeof (symrec));
+  res->name = strdup (name);
+  res->type = sym_type;
+  res->value.var = 0; // Set value to 0 even if fun.
+  res->next = sym_table;
+  sym_table = res;
+  return res;
+}
+
+symrec *
+getsym (char const *name)
+{
+  for (symrec *p = sym_table; p; p = p->next)
+    if (strcmp (p->name, name) == 0)
+      return p;
+  return NULL;
+}
+
+// How many symbols are registered.
+static int
+symbol_count (void)
+{
+  int res = 0;
+  for (symrec *p = sym_table; p; p = p->next)
+    ++res;
+  return res;
+}
+
+
+
+/*------------.
+| Locations.  |
+`------------*/
+
+// Print *LOC on OUT.  Do it in a compact way, that avoids redundancy.
+
+static void
+location_print (FILE *out, YYLTYPE const * const loc)
+{
+  fprintf (out, "%d.%d", loc->first_line, loc->first_column);
+
+  int end_col = 0 != loc->last_column ? loc->last_column - 1 : 0;
+  if (loc->first_line < loc->last_line)
+    fprintf (out, "-%d.%d", loc->last_line, end_col);
+  else if (loc->first_column < end_col)
+    fprintf (out, "-%d", end_col);
+}
+
+
+/*----------.
+| Scanner.  |
+`----------*/
+
+yytoken_kind_t
+yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc,
+       const user_context *uctx)
+{
+  int c;
+
+  // Ignore white space, get first nonwhite character.
+  do {
+    // Move the first position onto the last.
+    yylloc->first_line = yylloc->last_line;
+    yylloc->first_column = yylloc->last_column;
+
+    yylloc->last_column += 1;
+    c = *((*line)++);
+  } while (c == ' ' || c == '\t');
+
+  switch (c)
+    {
+    case '+': return TOK_PLUS;
+    case '-': return TOK_MINUS;
+    case '*': return TOK_STAR;
+    case '/': return TOK_SLASH;
+    case '^': return TOK_CARET;
+    case '=': return TOK_EQUAL;
+    case '(': return TOK_LPAREN;
+    case ')': return TOK_RPAREN;
+
+    case '!': return TOK_YYUNDEF;
+
+    case '\0': return TOK_YYEOF;
+
+      // Numbers.
+    case '.':
+    case '0': case '1': case '2': case '3': case '4':
+    case '5': case '6': case '7': case '8': case '9':
+      {
+        int nchars = 0;
+        if (sscanf (*line - 1, "%lf%n", &yylval->TOK_NUM, &nchars) != 1)
+          abort ();
+        *line += nchars - 1;
+        yylloc->last_column += nchars - 1;
+        return TOK_NUM;
+      }
+
+      // Identifiers.
+    case 'a': case 'b': case 'c': case 'd': case 'e':
+    case 'f': case 'g': case 'h': case 'i': case 'j':
+    case 'k': case 'l': case 'm': case 'n': case 'o':
+    case 'p': case 'q': case 'r': case 's': case 't':
+    case 'u': case 'v': case 'w': case 'x': case 'y':
+    case 'z':
+      {
+        int nchars = 0;
+        char buf[100];
+        if (sscanf (*line - 1, "%99[a-z]%n", buf, &nchars) != 1)
+          abort ();
+        *line += nchars - 1;
+        yylloc->last_column += nchars - 1;
+        if (strcmp (buf, "exit") == 0)
+          return TOK_EXIT;
+        else
+          {
+            symrec *s = getsym (buf);
+            if (!s)
+              s = putsym (buf, TOK_VAR);
+            yylval->TOK_VAR = s;
+            return s->type;
+          }
+      }
+
+      // Stray characters.
+    default:
+      yyerror (yylloc, uctx, _("syntax error: invalid character: %c"), c);
+      return TOK_YYerror;
+    }
+}
+
+
+/*---------.
+| Parser.  |
+`---------*/
+
+
+static const char *
+error_format_string (int argc)
+{
+  switch (argc)
+    {
+    default: // Avoid compiler warnings.
+    case 0: return _("%@: syntax error");
+    case 1: return _("%@: syntax error: unexpected %u");
+      // TRANSLATORS: '%@' is a location in a file, '%u' is an
+      // "unexpected token", and '%0e', '%1e'... are expected tokens
+      // at this point.
+      //
+      // For instance on the expression "1 + * 2", you'd get
+      //
+      // 1.5: syntax error: expected - or ( or number or function or variable before *
+    case 2: return _("%@: syntax error: expected %0e before %u");
+    case 3: return _("%@: syntax error: expected %0e or %1e before %u");
+    case 4: return _("%@: syntax error: expected %0e or %1e or %2e before %u");
+    case 5: return _("%@: syntax error: expected %0e or %1e or %2e or %3e before %u");
+    case 6: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e before %u");
+    case 7: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e or %5e before %u");
+    case 8: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e or %5e etc., before %u");
+    }
+}
+
+
+int
+yyreport_syntax_error (const yypcontext_t *ctx, const user_context *uctx)
+{
+  if (uctx->silent)
+    return 0;
+
+  enum { ARGS_MAX = 6 };
+  yysymbol_kind_t arg[ARGS_MAX];
+  int argsize = yypcontext_expected_tokens (ctx, arg, ARGS_MAX);
+  if (argsize < 0)
+    return argsize;
+  const int too_many_expected_tokens = argsize == 0 && arg[0] != YYSYMBOL_YYEMPTY;
+  if (too_many_expected_tokens)
+    argsize = ARGS_MAX;
+  const char *format = error_format_string (1 + argsize + too_many_expected_tokens);
+
+  const YYLTYPE *loc = yypcontext_location (ctx);
+  while (*format)
+    // %@: location.
+    if (format[0] == '%' && format[1] == '@')
+      {
+        YYLOCATION_PRINT (stderr, loc);
+        format += 2;
+      }
+    // %u: unexpected token.
+    else if (format[0] == '%' && format[1] == 'u')
+      {
+        fputs (yysymbol_name (yypcontext_token (ctx)), stderr);
+        format += 2;
+      }
+    // %0e, %1e...: expected token.
+    else if (format[0] == '%'
+             && isdigit ((unsigned char) format[1])
+             && format[2] == 'e'
+             && (format[1] - '0') < argsize)
+      {
+        int i = format[1] - '0';
+        fputs (yysymbol_name (arg[i]), stderr);
+        format += 3;
+      }
+    else
+      {
+        fputc (*format, stderr);
+        ++format;
+      }
+  fputc ('\n', stderr);
+
+  // Quote the source line.
+  {
+    fprintf (stderr, "%5d | %s\n", loc->first_line, uctx->line);
+    fprintf (stderr, "%5s | %*s", "", loc->first_column, "^");
+    for (int i = loc->last_column - loc->first_column - 1; 0 < i; --i)
+      putc ('~', stderr);
+    putc ('\n', stderr);
+  }
+  return 0;
+}
+
+
+// Called by yyparse on errors to report the error to the user.
+void
+yyerror (const YYLTYPE *loc, const user_context *uctx, char const *format, ...)
+{
+  if (uctx->silent)
+    return;
+
+  YYLOCATION_PRINT (stderr, loc);
+  fputs (": ", stderr);
+  va_list args;
+  va_start (args, format);
+  vfprintf (stderr, format, args);
+  va_end (args);
+  putc ('\n', stderr);
+}
+
+
+// Return a newly allocated copy of at most N bytes of STRING.  In
+// other words, return a copy of the initial segment of length N of
+// STRING.
+static char *
+xstrndup (const char *string, size_t n)
+{
+  // len = strnlen (string, n), portably.
+  const char *end = memchr (string, '\0', n);
+  size_t len = end ? (size_t) (end - string) : n;
+  char *new = malloc (len + 1);
+  if (!new)
+    abort ();
+  new[len] = '\0';
+  return memcpy (new, string, len);
+}
+
+
+/*-----------.
+| Readline.  |
+`-----------*/
+
+// Parse (and execute) this line.
+static int
+process_line (YYLTYPE *lloc, const char *line)
+{
+  user_context uctx = {0, line};
+  yypstate *ps = yypstate_new ();
+  int status = 0;
+  do {
+    YYSTYPE lval;
+    yytoken_kind_t token = yylex (&line, &lval, lloc, &uctx);
+    status = yypush_parse (ps, token, &lval, lloc, &uctx);
+  } while (status == YYPUSH_MORE);
+  yypstate_delete (ps);
+  lloc->last_line++;
+  lloc->last_column = 1;
+  return status;
+}
+
+// Get the list of possible tokens after INPUT was read.
+// Returns a nonnegative.
+static int
+expected_tokens (const char *input,
+                 int *tokens, int ntokens)
+{
+  YYDPRINTF ((stderr, "expected_tokens (\"%s\")", input));
+  user_context uctx = {1, input};
+
+  // Parse the current state of the line.
+  yypstate *ps = yypstate_new ();
+  int status = 0;
+  YYLTYPE lloc = { 1, 1, 1, 1 };
+  do {
+    YYSTYPE lval;
+    yytoken_kind_t token = yylex (&input, &lval, &lloc, &uctx);
+    // Don't let the parse know when we reach the end of input.
+    if (token == TOK_YYEOF)
+      break;
+    status = yypush_parse (ps, token, &lval, &lloc, &uctx);
+  } while (status == YYPUSH_MORE);
+
+  int res = 0;
+  // If there were parse errors, don't propose completions.
+  if (!ps->yynerrs)
+    {
+      // Then query for the accepted tokens at this point.
+      res = yypstate_expected_tokens (ps, tokens, ntokens);
+      if (res < 0)
+        abort ();
+    }
+  yypstate_delete (ps);
+  return res;
+}
+
+// Attempt to complete on the contents of TEXT.  START and END bound
+// the region of rl_line_buffer that contains the word to complete.
+// TEXT is the word to complete.  We can use the entire contents of
+// rl_line_buffer in case we want to do some simple parsing.  Return
+// the array of matches, or NULL if there aren't any.
+static char **
+completion (const char *text, int start, int end)
+{
+  YYDPRINTF ((stderr, "completion (\"%.*s[%.*s]%s\")\n",
+              start, rl_line_buffer,
+              end - start, rl_line_buffer + start,
+              rl_line_buffer + end));
+
+  // Get list of token numbers.
+  int tokens[YYNTOKENS];
+  char *line = xstrndup (rl_line_buffer, (size_t) start);
+  int ntokens = expected_tokens (line, tokens, YYNTOKENS);
+  free (line);
+
+  // Build MATCHES, the list of possible completions.
+  const size_t len = strlen (text);
+  // Need initial prefix and final NULL.
+  char **matches
+    = calloc ((size_t) ntokens + (size_t) symbol_count () + 2, sizeof *matches);
+  if (!matches)
+    abort ();
+  int match = 1;
+  for (int i = 0; i < ntokens; ++i)
+    switch (tokens[i])
+      {
+      case YYSYMBOL_FUN:
+        for (symrec *s = sym_table; s; s = s->next)
+          if (s->type == TOK_FUN && strncmp (text, s->name, len) == 0)
+            matches[match++] = strdup (s->name);
+        break;
+      case YYSYMBOL_VAR:
+        for (symrec *s = sym_table; s; s = s->next)
+          if (s->type == TOK_VAR && strncmp (text, s->name, len) == 0)
+            matches[match++] = strdup (s->name);
+        break;
+      default:
+        {
+          const char* token = yysymbol_name (tokens[i]);
+          if (strncmp (text, token, len) == 0)
+            matches[match++] = strdup (token);
+          break;
+        }
+      }
+
+  // Find the longest common prefix, and install it in matches[0], as
+  // required by readline.
+  if (match == 1)
+    matches[0] = strdup (text);
+  else
+    {
+      size_t lcplen = strlen (matches[1]);
+      for (int i = 2; i < match && lcplen; ++i)
+        for (size_t j = 0; j < lcplen; ++j)
+          if (matches[1][j] != matches[i][j])
+            lcplen = j;
+      matches[0] = xstrndup (matches[1], lcplen);
+    }
+
+  if (yydebug)
+    {
+      fprintf (stderr, "completion (\"%.*s[%.*s]%s\") = ",
+               start, rl_line_buffer,
+               end - start, rl_line_buffer + start,
+               rl_line_buffer + end);
+      for (int i = 1; matches[i]; ++i)
+        fprintf (stderr, "%s%s",
+                 i == 1 ? "{" : ", ",
+                 matches[i]);
+      fprintf (stderr, "}\n");
+    }
+
+  // Don't fall back to proposing file names.
+  rl_attempted_completion_over = 1;
+  return matches;
+}
+
+static void
+init_readline (void)
+{
+  // Allow conditional parsing of the ~/.inputrc file.
+  rl_readline_name = "bistromathic";
+
+  // Tell the completer that we want a crack first.
+  rl_attempted_completion_function = completion;
+
+  // The basic list of characters that signal a break between words
+  // for the completer routine.
+  rl_basic_word_break_characters = " \t\n\"\\'`@$><=;|&{(+-*/^)";
+}
+
+
+
+/*-------.
+| Main.  |
+`-------*/
+
+int
+main (int argc, char const* argv[])
+{
+#if defined ENABLE_NLS && ENABLE_NLS
+  // Set up internationalization.
+  setlocale (LC_ALL, "");
+  // Use Bison's standard translation catalog for error messages
+  // (the generated messages).
+  bindtextdomain ("bison-runtime", BISON_LOCALEDIR);
+  // The translation catalog of bistromathic is actually included in
+  // Bison's.  In your own project, use the name of your project.
+  bindtextdomain ("bison", LOCALEDIR);
+  textdomain ("bison");
+#endif
+
+  // Enable parse traces on option -p.
+  if (1 < argc && strcmp (argv[1], "-p") == 0)
+    yydebug = 1;
+  init_table ();
+  init_readline ();
+  YYLTYPE lloc = {1, 1, 1, 1};
+  while (!done)
+    {
+      char *line = readline ("> ");
+      if (!line)
+        {
+          // Finish the line started by the prompt.
+          putchar ('\n');
+          break;
+        }
+      if (*line)
+        add_history (line);
+      process_line (&lloc, line);
+      free (line);
+    }
+}

local/recipes/dev/bison/source/examples/c/calc/Makefile

@@ -0,0 +1,23 @@
+# This Makefile is designed to be simple and readable.  It does not
+# aim at portability.  It requires GNU Make.
+
+BASE = calc
+BISON = bison
+
+all: $(BASE)
+
+%.c %.h %.html %.xml %.gv: %.y
+	$(BISON) $(BISONFLAGS) --header --html --graph -o $*.c $<
+
+$(BASE): $(BASE).o
+	$(CC) $(CFLAGS) -o $@ $^
+
+run: $(BASE)
+	@echo "Type arithmetic expressions.  Quit with ctrl-d."
+	./$<
+
+CLEANFILES =									\
+  $(BASE) *.o $(BASE).[ch] $(BASE).output $(BASE).xml $(BASE).html $(BASE).gv
+
+clean:
+	rm -f $(CLEANFILES)

local/recipes/dev/bison/source/examples/c/calc/README.md

@@ -0,0 +1,23 @@
+# calc - calculator with Bison
+
+This directory contains calc, the traditional example of using Bison to
+build a simple calculator.
+
+<!---
+Local Variables:
+fill-column: 76
+ispell-dictionary: "american"
+End:
+
+Copyright (C) 2019-2021 Free Software Foundation, Inc.
+
+This file is part of Bison, the GNU Compiler Compiler.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts.  A copy of the license is included in the "GNU Free
+Documentation License" file as part of this distribution.
+
+--->

local/recipes/dev/bison/source/examples/c/calc/calc.test

@@ -0,0 +1,43 @@
+#! /bin/sh
+
+# Copyright (C) 2019-2021 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+cat >input <<EOF
+1+2*3
+EOF
+run 0 7
+
+cat >input <<EOF
+1 - 2 - 3
+EOF
+run 0 -4
+
+cat >input <<EOF
+8 / 2 / 2
+EOF
+run 0 2
+
+cat >input <<EOF
+(1+2) * 3
+EOF
+run 0 9
+# Check the traces.
+run -noerr 0 9 -p
+
+cat >input <<EOF
+1++2
+EOF
+run 0 "err: syntax error, unexpected '+', expecting number or '('"

local/recipes/dev/bison/source/examples/c/calc/calc.y

@@ -0,0 +1,102 @@
+%code top {
+  #include <assert.h>
+  #include <ctype.h>  /* isdigit. */
+  #include <stdio.h>  /* printf. */
+  #include <stdlib.h> /* abort. */
+  #include <string.h> /* strcmp. */
+
+  int yylex (void);
+  void yyerror (char const *);
+}
+
+%define api.header.include {"calc.h"}
+
+/* Generate YYSTYPE from the types used in %token and %type.  */
+%define api.value.type union
+%token <double> NUM "number"
+%type  <double> expr term fact
+
+/* Generate the parser description file (calc.output).  */
+%verbose
+
+/* Nice error messages with details. */
+%define parse.error detailed
+
+/* Enable run-time traces (yydebug).  */
+%define parse.trace
+
+/* Formatting semantic values in debug traces.  */
+%printer { fprintf (yyo, "%g", $$); } <double>;
+
+%% /* The grammar follows.  */
+input:
+  %empty
+| input line
+;
+
+line:
+  '\n'
+| expr '\n'  { printf ("%.10g\n", $1); }
+| error '\n' { yyerrok; }
+;
+
+expr:
+  expr '+' term { $$ = $1 + $3; }
+| expr '-' term { $$ = $1 - $3; }
+| term
+;
+
+term:
+  term '*' fact { $$ = $1 * $3; }
+| term '/' fact { $$ = $1 / $3; }
+| fact
+;
+
+fact:
+  "number"
+| '(' expr ')' { $$ = $2; }
+;
+
+%%
+
+int
+yylex (void)
+{
+  int c;
+
+  /* Ignore white space, get first nonwhite character.  */
+  while ((c = getchar ()) == ' ' || c == '\t')
+    continue;
+
+  if (c == EOF)
+    return 0;
+
+  /* Char starts a number => parse the number.         */
+  if (c == '.' || isdigit (c))
+    {
+      ungetc (c, stdin);
+      if (scanf ("%lf", &yylval.NUM) != 1)
+        abort ();
+      return NUM;
+    }
+
+  /* Any other character is a token by itself.        */
+  return c;
+}
+
+/* Called by yyparse on error.  */
+void
+yyerror (char const *s)
+{
+  fprintf (stderr, "%s\n", s);
+}
+
+int
+main (int argc, char const* argv[])
+{
+  /* Enable parse traces on option -p.  */
+  for (int i = 1; i < argc; ++i)
+    if (!strcmp (argv[i], "-p"))
+      yydebug = 1;
+  return yyparse ();
+}

local/recipes/dev/bison/source/examples/c/calc/local.mk

@@ -0,0 +1,34 @@
+## Copyright (C) 2019-2021 Free Software Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+calcdir = $(docdir)/%D%
+
+## ------ ##
+## Calc.  ##
+## ------ ##
+
+check_PROGRAMS += %D%/calc
+TESTS += %D%/calc.test
+EXTRA_DIST += %D%/calc.test
+nodist_%C%_calc_SOURCES = %D%/calc.y
+%D%/calc.c: $(dependencies)
+
+# Don't use gnulib's system headers.
+%C%_calc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_calc_CFLAGS = $(TEST_CFLAGS)
+
+dist_calc_DATA = %D%/calc.y %D%/Makefile %D%/README.md
+CLEANFILES += %D%/calc.[ch] %D%/calc.output %D%/scan.c
+CLEANDIRS += %D%/*.dSYM

local/recipes/dev/bison/source/examples/c/glr/Makefile

@@ -0,0 +1,23 @@
+# This Makefile is designed to be simple and readable.  It does not
+# aim at portability.  It requires GNU Make.
+
+BASE = c++-types
+BISON = bison
+
+all: $(BASE)
+
+%.c %.h %.xml %.gv: %.y
+	$(BISON) $(BISONFLAGS) --header --graph -o $*.c $<
+
+$(BASE): $(BASE).o
+	$(CC) $(CFLAGS) -o $@ $^
+
+run: $(BASE)
+	@echo "Type C++ declarations or expressions.  Quit with ctrl-d."
+	./$<
+
+CLEANFILES =									\
+  $(BASE) *.o $(BASE).[ch] $(BASE).output $(BASE).xml $(BASE).html $(BASE).gv
+
+clean:
+	rm -f $(CLEANFILES)

local/recipes/dev/bison/source/examples/c/glr/README.md

@@ -0,0 +1,24 @@
+# glr
+
+This example demonstrates the use of GLR parsers to handle (local)
+ambiguities in the C++ language.  See the node "Merging GLR Parses" in
+Bison's documentation.
+
+<!---
+Local Variables:
+fill-column: 76
+ispell-dictionary: "american"
+End:
+
+Copyright (C) 2020-2021 Free Software Foundation, Inc.
+
+This file is part of Bison, the GNU Compiler Compiler.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts.  A copy of the license is included in the "GNU Free
+Documentation License" file as part of this distribution.
+
+--->

local/recipes/dev/bison/source/examples/c/glr/c++-types.test

@@ -0,0 +1,47 @@
+#! /bin/sh
+
+# Copyright (C) 2020-2021 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+cat >input <<EOF
+z + q;
+
+T x;
+
+T x = y;
+
+x = y;
+
+T (x) + y;
+
+T (x);
+
+T (y) = z + q;
+
+T (y y) = z + q;
+
+z + q;
+EOF
+run 0 "\
+1.0-5: +(z, q)
+3.0-3: <declare>(T, x)
+5.0-7: <init-declare>(T, x, y)
+7.0-5: =(x, y)
+9.0-9: +(<cast>(x, T), y)
+11.0-5: <OR>(<declare>(T, x), <cast>(x, T))
+13.0-13: <OR>(<init-declare>(T, y, +(z, q)), =(<cast>(y, T), +(z, q)))
+15.0-15: <error>
+17.0-5: +(z, q)
+err: 15.5: syntax error, unexpected identifier, expecting '=' or '+' or ')'"

local/recipes/dev/bison/source/examples/c/glr/c++-types.y

@@ -0,0 +1,340 @@
+/*                                                       -*- C -*-
+  Copyright (C) 2020-2021 Free Software Foundation, Inc.
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/* Simplified C++ Type and Expression Grammar.
+   Written by Paul Hilfinger for Bison's test suite.  */
+
+%define api.pure
+%header
+%define api.header.include {"c++-types.h"}
+%locations
+%debug
+
+/* Nice error messages with details. */
+%define parse.error detailed
+
+%code requires
+{
+  union Node {
+    struct {
+      int isNterm;
+      int parents;
+    } nodeInfo;
+    struct {
+      int isNterm; /* 1 */
+      int parents;
+      char const *form;
+      union Node *children[3];
+    } nterm;
+    struct {
+      int isNterm; /* 0 */
+      int parents;
+      char *text;
+    } term;
+  };
+  typedef union Node Node;
+}
+
+%define api.value.type union
+
+%code
+{
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+  static Node *new_nterm (char const *, Node *, Node *, Node *);
+  static Node *new_term (char *);
+  static void free_node (Node *);
+  static char *node_to_string (const Node *);
+  static void node_print (FILE *, const Node *);
+  static Node *stmt_merge (YYSTYPE x0, YYSTYPE x1);
+
+  static void yyerror (YYLTYPE const * const loc, const char *msg);
+  static yytoken_kind_t yylex (YYSTYPE *lval, YYLTYPE *lloc);
+}
+
+%expect-rr 1
+
+%token
+  TYPENAME "typename"
+  ID "identifier"
+
+%right '='
+%left '+'
+
+%glr-parser
+
+%type <Node *> stmt expr decl declarator TYPENAME ID
+%destructor { free_node ($$); } <Node *>
+%printer { node_print (yyo, $$); } <Node *>
+
+%%
+
+prog : %empty
+     | prog stmt   {
+                     YYLOCATION_PRINT (stdout, &@2);
+                     fputs (": ", stdout);
+                     node_print (stdout, $2);
+                     putc ('\n', stdout);
+                     fflush (stdout);
+                     free_node ($2);
+                   }
+     ;
+
+stmt : expr ';'  %merge <stmt_merge>     { $$ = $1; }
+     | decl      %merge <stmt_merge>
+     | error ';'        { $$ = new_nterm ("<error>", NULL, NULL, NULL); }
+     ;
+
+expr : ID
+     | TYPENAME '(' expr ')'
+                        { $$ = new_nterm ("<cast>(%s, %s)", $3, $1, NULL); }
+     | expr '+' expr    { $$ = new_nterm ("+(%s, %s)", $1, $3, NULL); }
+     | expr '=' expr    { $$ = new_nterm ("=(%s, %s)", $1, $3, NULL); }
+     ;
+
+decl : TYPENAME declarator ';'
+                        { $$ = new_nterm ("<declare>(%s, %s)", $1, $2, NULL); }
+     | TYPENAME declarator '=' expr ';'
+                        { $$ = new_nterm ("<init-declare>(%s, %s, %s)", $1,
+                                          $2, $4); }
+     ;
+
+declarator
+     : ID
+     | '(' declarator ')' { $$ = $2; }
+     ;
+
+%%
+
+/* A C error reporting function.  */
+static void
+yyerror (YYLTYPE const * const loc, const char *msg)
+{
+  YYLOCATION_PRINT (stderr, loc);
+  fprintf (stderr, ": %s\n", msg);
+}
+
+/* The input file. */
+FILE * input = NULL;
+
+yytoken_kind_t
+yylex (YYSTYPE *lval, YYLTYPE *lloc)
+{
+  static int lineNum = 1;
+  static int colNum = 0;
+
+  while (1)
+    {
+      int c;
+      assert (!feof (input));
+      c = getc (input);
+      switch (c)
+        {
+        case EOF:
+          return 0;
+        case '\t':
+          colNum = (colNum + 7) & ~7;
+          break;
+        case ' ': case '\f':
+          colNum += 1;
+          break;
+        case '\n':
+          lineNum += 1;
+          colNum = 0;
+          break;
+        default:
+          {
+            yytoken_kind_t tok;
+            lloc->first_line = lloc->last_line = lineNum;
+            lloc->first_column = colNum;
+            if (isalpha (c))
+              {
+                char buffer[256];
+                unsigned i = 0;
+
+                do
+                  {
+                    buffer[i++] = (char) c;
+                    colNum += 1;
+                    assert (i != sizeof buffer - 1);
+                    c = getc (input);
+                  }
+                while (isalnum (c) || c == '_');
+
+                ungetc (c, input);
+                buffer[i++] = 0;
+                if (isupper ((unsigned char) buffer[0]))
+                  {
+                    tok = TYPENAME;
+                    lval->TYPENAME = new_term (strcpy (malloc (i), buffer));
+                  }
+                else
+                  {
+                    tok = ID;
+                    lval->ID = new_term (strcpy (malloc (i), buffer));
+                  }
+              }
+            else
+              {
+                colNum += 1;
+                tok = c;
+              }
+            lloc->last_column = colNum;
+            return tok;
+          }
+        }
+    }
+}
+
+static Node *
+new_nterm (char const *form, Node *child0, Node *child1, Node *child2)
+{
+  Node *res = malloc (sizeof *res);
+  res->nterm.isNterm = 1;
+  res->nterm.parents = 0;
+  res->nterm.form = form;
+  res->nterm.children[0] = child0;
+  if (child0)
+    child0->nodeInfo.parents += 1;
+  res->nterm.children[1] = child1;
+  if (child1)
+    child1->nodeInfo.parents += 1;
+  res->nterm.children[2] = child2;
+  if (child2)
+    child2->nodeInfo.parents += 1;
+  return res;
+}
+
+static Node *
+new_term (char *text)
+{
+  Node *res = malloc (sizeof *res);
+  res->term.isNterm = 0;
+  res->term.parents = 0;
+  res->term.text = text;
+  return res;
+}
+
+static void
+free_node (Node *node)
+{
+  if (!node)
+    return;
+  node->nodeInfo.parents -= 1;
+  /* Free only if 0 (last parent) or -1 (no parents).  */
+  if (node->nodeInfo.parents > 0)
+    return;
+  if (node->nodeInfo.isNterm == 1)
+    {
+      free_node (node->nterm.children[0]);
+      free_node (node->nterm.children[1]);
+      free_node (node->nterm.children[2]);
+    }
+  else
+    free (node->term.text);
+  free (node);
+}
+
+static char *
+node_to_string (const Node *node)
+{
+  char *res;
+  if (!node)
+    {
+      res = malloc (1);
+      res[0] = 0;
+    }
+  else if (node->nodeInfo.isNterm == 1)
+    {
+      char *child0 = node_to_string (node->nterm.children[0]);
+      char *child1 = node_to_string (node->nterm.children[1]);
+      char *child2 = node_to_string (node->nterm.children[2]);
+      res = malloc (strlen (node->nterm.form) + strlen (child0)
+                    + strlen (child1) + strlen (child2) + 1);
+      sprintf (res, node->nterm.form, child0, child1, child2);
+      free (child2);
+      free (child1);
+      free (child0);
+    }
+  else
+    res = strdup (node->term.text);
+  return res;
+}
+
+static void
+node_print (FILE *out, const Node *n)
+{
+  char *str = node_to_string (n);
+  fputs (str, out);
+  free (str);
+}
+
+
+static Node *
+stmt_merge (YYSTYPE x0, YYSTYPE x1)
+{
+  return new_nterm ("<OR>(%s, %s)", x0.stmt, x1.stmt, NULL);
+}
+
+static int
+process (const char *file)
+{
+  int is_stdin = !file || strcmp (file, "-") == 0;
+  if (is_stdin)
+    input = stdin;
+  else
+    input = fopen (file, "r");
+  assert (input);
+  int status = yyparse ();
+  if (!is_stdin)
+    fclose (input);
+  return status;
+}
+
+int
+main (int argc, char **argv)
+{
+  if (getenv ("YYDEBUG"))
+    yydebug = 1;
+
+  int ran = 0;
+  for (int i = 1; i < argc; ++i)
+    // Enable parse traces on option -p.
+    if (strcmp (argv[i], "-p") == 0)
+      yydebug = 1;
+    else
+      {
+        int status = process (argv[i]);
+        ran = 1;
+        if (!status)
+          return status;
+      }
+
+  if (!ran)
+    {
+      int status = process (NULL);
+      if (!status)
+        return status;
+    }
+  return 0;
+}

local/recipes/dev/bison/source/examples/c/glr/local.mk

@@ -0,0 +1,34 @@
+## Copyright (C) 2020-2021 Free Software Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+glrdir = $(docdir)/%D%
+
+## ----------- ##
+## c++-types.  ##
+## ----------- ##
+
+check_PROGRAMS += %D%/c++-types
+TESTS += %D%/c++-types.test
+EXTRA_DIST += %D%/c++-types.test
+nodist_%C%_c___types_SOURCES = %D%/c++-types.y
+%D%/c++-types.c: $(dependencies)
+
+# Don't use gnulib's system headers.
+%C%_c___types_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_c___types_CFLAGS = $(TEST_CFLAGS)
+
+dist_glr_DATA = %D%/c++-types.y %D%/Makefile %D%/README.md
+CLEANFILES += %D%/c++-types.[ch] %D%/c++-types.output
+CLEANDIRS += %D%/*.dSYM

local/recipes/dev/bison/source/examples/c/lexcalc/Makefile

@@ -0,0 +1,29 @@
+# This Makefile is designed to be simple and readable.  It does not
+# aim at portability.  It requires GNU Make.
+
+BASE = lexcalc
+BISON = bison
+FLEX = flex
+
+all: $(BASE)
+
+%.c %.h %.html %.xml %.gv: %.y
+	$(BISON) $(BISONFLAGS) --header --html --graph -o $*.c $<
+
+%.c: %.l
+	$(FLEX) $(FLEXFLAGS) -o$@ $<
+
+scan.o: parse.h
+$(BASE): parse.o scan.o
+	$(CC) $(CFLAGS) -o $@ $^
+
+run: $(BASE)
+	@echo "Type arithmetic expressions.  Quit with ctrl-d."
+	./$<
+
+CLEANFILES =						\
+  $(BASE) *.o						\
+  parse.[ch] parse.output parse.xml parse.html parse.gv	\
+  scan.c
+clean:
+	rm -f $(CLEANFILES)

local/recipes/dev/bison/source/examples/c/lexcalc/README.md

@@ -0,0 +1,24 @@
+# lexcalc - calculator with Flex and Bison
+
+This directory contains lexcalc, the traditional example of using Flex and
+Bison to build a simple calculator.
+
+It features detailed syntax errors with locations.
+
+<!---
+Local Variables:
+fill-column: 76
+ispell-dictionary: "american"
+End:
+
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
+
+This file is part of Bison, the GNU Compiler Compiler.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts.  A copy of the license is included in the "GNU Free
+Documentation License" file as part of this distribution.
+--->

local/recipes/dev/bison/source/examples/c/lexcalc/lexcalc.test

@@ -0,0 +1,46 @@
+#! /bin/sh
+
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+cat >input <<EOF
+1+2*3
+EOF
+run 0 7
+
+cat >input <<EOF
+1
+2
+3
+EOF
+run 0 '1
+2
+3'
+
+cat >input <<EOF
+(1+2) * 3
+EOF
+run 0 9
+run -noerr 0 9 -p
+
+cat >input <<EOF
+(1+2) *
+EOF
+run 1 'err: 1.8-2.0: syntax error, unexpected end of line, expecting ( or number'
+
+cat >input <<EOF
+1 / (2 - 2)
+EOF
+run 1 'err: 1.1-11: error: division by zero'

local/recipes/dev/bison/source/examples/c/lexcalc/local.mk

@@ -0,0 +1,44 @@
+## Copyright (C) 2018-2021 Free Software Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+lexcalcdir = $(docdir)/%D%
+
+## --------- ##
+## LexCalc.  ##
+## --------- ##
+
+if FLEX_WORKS
+  check_PROGRAMS += %D%/lexcalc
+  TESTS += %D%/lexcalc.test
+  nodist_%C%_lexcalc_SOURCES = %D%/parse.y %D%/parse.h %D%/scan.l
+  # Don't use gnulib's system headers.
+  %C%_lexcalc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+  # Fighting warnings triggered by Flex is just too painful.
+  # %C%_lexcalc_CFLAGS = $(TEST_CFLAGS)
+endif FLEX_WORKS
+
+%D%/parse.c: $(dependencies)
+
+# Tell Make scan.o depends on parse.h, except that Make sees only
+# parse.c, not parse.h.  We can't use BUILT_SOURCES to this end, since
+# we use the built bison.
+%D%/lexcalc$(DASH)scan.o: %D%/parse.c
+# Likewise, but for Automake before 1.16.
+%D%/examples_c_lexcalc_lexcalc$(DASH)scan.o: %D%/parse.c
+
+EXTRA_DIST += %D%/lexcalc.test
+dist_lexcalc_DATA = %D%/parse.y %D%/scan.l %D%/Makefile %D%/README.md
+CLEANFILES += %D%/parse.[ch] %D%/scan.c %D%/parse.output
+CLEANDIRS += %D%/*.dSYM

local/recipes/dev/bison/source/examples/c/lexcalc/parse.y

@@ -0,0 +1,138 @@
+/* Parser for lexcalc.   -*- C -*-
+
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+// Prologue (directives).
+%expect 0
+
+// Emitted in the header file, after the definition of YYSTYPE.
+%code provides
+{
+  // Tell Flex the expected prototype of yylex.
+#define YY_DECL                                 \
+  yytoken_kind_t yylex (YYSTYPE* yylval, YYLTYPE *yylloc, int *nerrs)
+  YY_DECL;
+
+  void yyerror (const YYLTYPE *loc, int *nerrs, const char *msg);
+}
+
+// Emitted on top of the implementation file.
+%code top
+{
+#include <stdio.h>  // printf.
+#include <stdlib.h> // getenv.
+#include <string.h> // strcmp.
+}
+
+// Include the header in the implementation rather than duplicating it.
+%define api.header.include {"parse.h"}
+
+// Don't share global variables between the scanner and the parser.
+%define api.pure full
+
+// To avoid name clashes (e.g., with C's EOF) prefix token definitions
+// with TOK_ (e.g., TOK_EOF).
+%define api.token.prefix {TOK_}
+
+// %token and %type use genuine types (e.g., "%token <int>").  Let
+// %bison define YYSTYPE as a union of all these types.
+%define api.value.type union
+
+// Generate detailed error messages.
+%define parse.error detailed
+
+// with locations.
+%locations
+
+// Enable debug traces (see yydebug in main).
+%define parse.trace
+
+// Error count, exchanged between main, yyparse and yylex.
+%param {int *nerrs}
+
+%token
+  PLUS   "+"
+  MINUS  "-"
+  STAR   "*"
+  SLASH  "/"
+  LPAREN "("
+  RPAREN ")"
+  EOL    "end of line"
+;
+
+%token <int> NUM "number"
+%type <int> exp
+%printer { fprintf (yyo, "%d", $$); } <int>
+
+// Precedence (from lowest to highest) and associativity.
+%left "+" "-"
+%left "*" "/"
+
+%%
+// Rules.
+input:
+  %empty
+| input line
+;
+
+line:
+  exp EOL   { printf ("%d\n", $exp); }
+| error EOL { yyerrok; }
+;
+
+exp:
+  exp "+" exp   { $$ = $1 + $3; }
+| exp "-" exp   { $$ = $1 - $3; }
+| exp "*" exp   { $$ = $1 * $3; }
+| exp "/" exp
+  {
+    if ($3 == 0)
+      {
+        yyerror (&@$, nerrs, "error: division by zero");
+        YYERROR;
+      }
+    else
+      $$ = $1 / $3;
+  }
+| "(" exp ")"   { $$ = $2; }
+| NUM           { $$ = $1; }
+;
+%%
+// Epilogue (C code).
+
+void yyerror (const YYLTYPE *loc, int *nerrs, const char *msg)
+{
+  YYLOCATION_PRINT (stderr, loc);
+  fprintf (stderr, ": %s\n", msg);
+  ++*nerrs;
+}
+
+int main (int argc, const char *argv[])
+{
+  // Possibly enable parser runtime debugging.
+  yydebug = !!getenv ("YYDEBUG");
+  // Enable parse traces on option -p.
+  for (int i = 1; i < argc; ++i)
+    if (strcmp (argv[i], "-p") == 0)
+      yydebug = 1;
+
+  int nerrs = 0;
+  yyparse (&nerrs);
+  // Exit on failure if there were errors.
+  return !!nerrs;
+}

local/recipes/dev/bison/source/examples/c/lexcalc/scan.l

@@ -0,0 +1,78 @@
+/* Scanner for lexcalc.   -*- C -*-
+
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Prologue (directives). */
+
+/* Disable Flex features we don't need, to avoid warnings. */
+%option nodefault noinput nounput noyywrap
+
+%{
+#include <errno.h>  /* errno, ERANGE */
+#include <limits.h> /* INT_MIN */
+#include <stdlib.h> /* strtol */
+
+#include "parse.h"
+
+  // Each time a rule is matched, advance the end cursor/position.
+#define YY_USER_ACTION                          \
+  yylloc->last_column += (int) yyleng;
+
+  // Move the first position onto the last.
+#define LOCATION_STEP()                         \
+  do {                                          \
+    yylloc->first_line = yylloc->last_line;     \
+    yylloc->first_column = yylloc->last_column; \
+  } while (0)
+%}
+
+%%
+%{
+  // Each time yylex is called, move the head position to the end one.
+  LOCATION_STEP ();
+%}
+ /* Rules.  */
+
+"+"      return TOK_PLUS;
+"-"      return TOK_MINUS;
+"*"      return TOK_STAR;
+"/"      return TOK_SLASH;
+
+"("      return TOK_LPAREN;
+")"      return TOK_RPAREN;
+
+ /* Scan an integer.  */
+[0-9]+   {
+  errno = 0;
+  long n = strtol (yytext, NULL, 10);
+  if (! (INT_MIN <= n && n <= INT_MAX && errno != ERANGE))
+    yyerror (yylloc, nerrs, "integer is out of range");
+  yylval->TOK_NUM = (int) n;
+  return TOK_NUM;
+}
+
+"\n"     yylloc->last_line++; yylloc->last_column = 1; return TOK_EOL;
+
+ /* Ignore white spaces. */
+[ \t]+   LOCATION_STEP (); continue;
+
+.        yyerror (yylloc, nerrs, "syntax error, invalid character"); continue;
+
+<<EOF>>  return TOK_YYEOF;
+%%
+/* Epilogue (C code). */

local/recipes/dev/bison/source/examples/c/local.mk

@@ -0,0 +1,26 @@
+## Copyright (C) 2018-2021 Free Software Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+cdir = $(docdir)/%D%
+dist_c_DATA = %D%/README.md
+
+include %D%/bistromathic/local.mk
+include %D%/calc/local.mk
+include %D%/glr/local.mk
+include %D%/lexcalc/local.mk
+include %D%/mfcalc/local.mk
+include %D%/pushcalc/local.mk
+include %D%/reccalc/local.mk
+include %D%/rpcalc/local.mk

local/recipes/dev/bison/source/examples/c/mfcalc/Makefile

@@ -0,0 +1,20 @@
+# This Makefile is designed to be simple and readable.  It does not
+# aim at portability.  It requires GNU Make.
+
+BASE = mfcalc
+BISON = bison
+
+all: $(BASE)
+
+%.c %.html %.gv: %.y
+	$(BISON) $(BISONFLAGS) --html --graph -o $*.c $<
+
+%: %.c
+	$(CC) $(CFLAGS) -o $@ $<
+
+run: $(BASE)
+	@echo "Type arithmetic expressions.  Quit with ctrl-d."
+	./$<
+
+clean:
+	rm -f $(BASE) $(BASE).c $(BASE).html $(BASE).xml $(BASE).gv $(BASE).output

local/recipes/dev/bison/source/examples/c/mfcalc/calc.h

@@ -0,0 +1,43 @@
+/* Functions for mfcalc.   -*- C -*-
+
+   Copyright (C) 1988-1993, 1995, 1998-2015, 2018-2021 Free Software
+   Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Function type. */
+typedef double (func_t) (double);
+
+/* Data type for links in the chain of symbols. */
+struct symrec
+{
+  char *name;  /* name of symbol */
+  int type;    /* type of symbol: either VAR or FUN */
+  union
+  {
+    double var;    /* value of a VAR */
+    func_t *fun;   /* value of a FUN */
+  } value;
+  struct symrec *next;  /* link field */
+};
+
+typedef struct symrec symrec;
+
+/* The symbol table: a chain of 'struct symrec'. */
+extern symrec *sym_table;
+
+symrec *putsym (char const *name, int sym_type);
+symrec *getsym (char const *name);

local/recipes/dev/bison/source/examples/c/mfcalc/local.mk

@@ -0,0 +1,45 @@
+## Copyright (C) 2005-2006, 2008-2015, 2018-2021 Free Software
+## Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+## -------------------- ##
+## Building & testing.  ##
+## -------------------- ##
+
+BUILT_SOURCES += $(mfcalc_sources)
+CLEANFILES +=  %D%/mfcalc.[ch] %D%/mfcalc.output
+CLEANDIRS += %D%/*.dSYM
+
+mfcalc_extracted = %D%/calc.h %D%/mfcalc.y
+mfcalc_sources = $(mfcalc_extracted)
+extracted += $(mfcalc_extracted)
+
+check_PROGRAMS += %D%/mfcalc
+nodist_%C%_mfcalc_SOURCES = $(mfcalc_sources)
+%D%/mfcalc.c: $(dependencies)
+# Don't use gnulib's system headers.
+%C%_mfcalc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_mfcalc_CFLAGS = $(TEST_CFLAGS)
+%C%_mfcalc_LDADD = -lm
+
+dist_TESTS += %D%/mfcalc.test
+
+## ------------ ##
+## Installing.  ##
+## ------------ ##
+
+mfcalcdir = $(docdir)/%D%
+mfcalc_DATA = $(mfcalc_extracted)
+dist_mfcalc_DATA = %D%/Makefile

local/recipes/dev/bison/source/examples/c/mfcalc/mfcalc.test

@@ -0,0 +1,39 @@
+#! /bin/sh
+
+# Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+cat >input <<EOF
+1+2*3
+EOF
+run 0 7
+
+cat >input <<EOF
+(1+2) * 3
+EOF
+run 0 9
+run -noerr 0 9 -p
+
+cat >input <<EOF
+a = 256
+sqrt (a)
+EOF
+run 0 '256
+16'
+
+cat >input <<EOF
+16 == 12
+EOF
+run 0 'err: syntax error'

local/recipes/dev/bison/source/examples/c/mfcalc/mfcalc.y

@@ -0,0 +1,208 @@
+/* Parser for mfcalc.   -*- C -*-
+
+   Copyright (C) 1988-1993, 1995, 1998-2015, 2018-2021 Free Software
+   Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+%{
+  #include <stdio.h>  /* For printf, etc. */
+  #include <math.h>   /* For pow, used in the grammar. */
+  #include "calc.h"   /* Contains definition of 'symrec'. */
+  int yylex (void);
+  void yyerror (char const *);
+%}
+
+%define api.value.type union /* Generate YYSTYPE from these types: */
+%token <double>  NUM     /* Double precision number. */
+%token <symrec*> VAR FUN /* Symbol table pointer: variable/function. */
+%nterm <double>  exp
+
+%precedence '='
+%left '-' '+'
+%left '*' '/'
+%precedence NEG /* negation--unary minus */
+%right '^'      /* exponentiation */
+/* Generate the parser description file. */
+%verbose
+/* Enable run-time traces (yydebug). */
+%define parse.trace
+
+/* Formatting semantic values. */
+%printer { fprintf (yyo, "%s", $$->name); } VAR;
+%printer { fprintf (yyo, "%s()", $$->name); } FUN;
+%printer { fprintf (yyo, "%g", $$); } <double>;
+%% /* The grammar follows. */
+input:
+  %empty
+| input line
+;
+
+line:
+  '\n'
+| exp '\n'   { printf ("%.10g\n", $1); }
+| error '\n' { yyerrok;                }
+;
+
+exp:
+  NUM
+| VAR                { $$ = $1->value.var;              }
+| VAR '=' exp        { $$ = $3; $1->value.var = $3;     }
+| FUN '(' exp ')'    { $$ = $1->value.fun ($3);         }
+| exp '+' exp        { $$ = $1 + $3;                    }
+| exp '-' exp        { $$ = $1 - $3;                    }
+| exp '*' exp        { $$ = $1 * $3;                    }
+| exp '/' exp        { $$ = $1 / $3;                    }
+| '-' exp  %prec NEG { $$ = -$2;                        }
+| exp '^' exp        { $$ = pow ($1, $3);               }
+| '(' exp ')'        { $$ = $2;                         }
+;
+/* End of grammar. */
+%%
+
+struct init
+{
+  char const *name;
+  func_t *fun;
+};
+
+struct init const funs[] =
+{
+  { "atan", atan },
+  { "cos",  cos  },
+  { "exp",  exp  },
+  { "ln",   log  },
+  { "sin",  sin  },
+  { "sqrt", sqrt },
+  { 0, 0 },
+};
+
+/* The symbol table: a chain of 'struct symrec'. */
+symrec *sym_table;
+
+/* Put functions in table. */
+static void
+init_table (void)
+{
+  for (int i = 0; funs[i].name; i++)
+    {
+      symrec *ptr = putsym (funs[i].name, FUN);
+      ptr->value.fun = funs[i].fun;
+    }
+}
+
+/* The mfcalc code assumes that malloc and realloc
+   always succeed, and that integer calculations
+   never overflow.  Production-quality code should
+   not make these assumptions.  */
+#include <assert.h>
+#include <stdlib.h> /* malloc, realloc. */
+#include <string.h> /* strlen. */
+
+symrec *
+putsym (char const *name, int sym_type)
+{
+  symrec *res = (symrec *) malloc (sizeof (symrec));
+  res->name = strdup (name);
+  res->type = sym_type;
+  res->value.var = 0; /* Set value to 0 even if fun. */
+  res->next = sym_table;
+  sym_table = res;
+  return res;
+}
+
+symrec *
+getsym (char const *name)
+{
+  for (symrec *p = sym_table; p; p = p->next)
+    if (strcmp (p->name, name) == 0)
+      return p;
+  return NULL;
+}
+
+#include <ctype.h>
+#include <stddef.h>
+
+int
+yylex (void)
+{
+  int c = getchar ();
+
+  /* Ignore white space, get first nonwhite character. */
+  while (c == ' ' || c == '\t')
+    c = getchar ();
+
+  if (c == EOF)
+    return YYEOF;
+
+  /* Char starts a number => parse the number. */
+  if (c == '.' || isdigit (c))
+    {
+      ungetc (c, stdin);
+      if (scanf ("%lf", &yylval.NUM) != 1)
+        abort ();
+      return NUM;
+    }
+
+  /* Char starts an identifier => read the name. */
+  if (isalpha (c))
+    {
+      static ptrdiff_t bufsize = 0;
+      static char *symbuf = 0;
+      ptrdiff_t i = 0;
+      do
+        {
+          /* If buffer is full, make it bigger. */
+          if (bufsize <= i)
+            {
+              bufsize = 2 * bufsize + 40;
+              symbuf = realloc (symbuf, (size_t) bufsize);
+            }
+          /* Add this character to the buffer. */
+          symbuf[i++] = (char) c;
+          /* Get another character. */
+          c = getchar ();
+        }
+      while (isalnum (c));
+
+      ungetc (c, stdin);
+      symbuf[i] = '\0';
+
+      symrec *s = getsym (symbuf);
+      if (!s)
+        s = putsym (symbuf, VAR);
+      yylval.VAR = s; /* or yylval.FUN = s. */
+      return s->type;
+    }
+
+  /* Any other character is a token by itself. */
+  return c;
+}
+
+/* Called by yyparse on error. */
+void yyerror (char const *s)
+{
+  fprintf (stderr, "%s\n", s);
+}
+
+int main (int argc, char const* argv[])
+{
+  /* Enable parse traces on option -p. */
+  if (argc == 2 && strcmp(argv[1], "-p") == 0)
+    yydebug = 1;
+  init_table ();
+  return yyparse ();
+}

local/recipes/dev/bison/source/examples/c/pushcalc/Makefile

@@ -0,0 +1,23 @@
+# This Makefile is designed to be simple and readable.  It does not
+# aim at portability.  It requires GNU Make.
+
+BASE = calc
+BISON = bison
+
+all: $(BASE)
+
+%.c %.h %.html %.gv: %.y
+	$(BISON) $(BISONFLAGS) --header --html --graph -o $*.c $<
+
+$(BASE): $(BASE).o
+	$(CC) $(CFLAGS) -o $@ $^
+
+run: $(BASE)
+	@echo "Type arithmetic expressions.  Quit with ctrl-d."
+	./$<
+
+CLEANFILES =									\
+  $(BASE) *.o $(BASE).[ch] $(BASE).output $(BASE).xml $(BASE).html $(BASE).gv
+
+clean:
+	rm -f $(CLEANFILES)

local/recipes/dev/bison/source/examples/c/pushcalc/README.md

@@ -0,0 +1,32 @@
+# pushcalc - push parser with Bison
+
+This directory contains pushcalc, the traditional calculator, implemented as
+a push parser.
+
+Traditionally Bison is used to create so called "pull parsers": the user
+invokes the parser once, which repeatedly calls (pulls) the scanner until
+the input is drained.
+
+This example demonstrates the "push parsers": the user calls scanner to
+fetch the next token, passes (pushes) it to the parser, and repeats the
+operation until the input is drained.
+
+This example is a straightforward conversion of the 'calc' example to the
+push-parser model.
+
+<!---
+Local Variables:
+fill-column: 76
+ispell-dictionary: "american"
+End:
+
+Copyright (C) 2020-2021 Free Software Foundation, Inc.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts.  A copy of the license is included in the "GNU Free
+Documentation License" file as part of this distribution.
+
+--->

local/recipes/dev/bison/source/examples/c/pushcalc/calc.test

@@ -0,0 +1,42 @@
+#! /bin/sh
+
+# Copyright (C) 2020-2021 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+cat >input <<EOF
+1+2*3
+EOF
+run 0 7
+
+cat >input <<EOF
+1 - 2 - 3
+EOF
+run 0 -4
+
+cat >input <<EOF
+8 / 2 / 2
+EOF
+run 0 2
+
+cat >input <<EOF
+(1+2) * 3
+EOF
+run 0 9
+run -noerr 0 9 -p
+
+cat >input <<EOF
+1++2
+EOF
+run 0 "err: syntax error, unexpected '+', expecting number or '('"

local/recipes/dev/bison/source/examples/c/pushcalc/calc.y

@@ -0,0 +1,134 @@
+/* Parser and scanner for pushcalc.   -*- C -*-
+
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+%code top {
+  #include <ctype.h>  /* isdigit. */
+  #include <stdio.h>  /* printf. */
+  #include <stdlib.h> /* abort. */
+  #include <string.h> /* strcmp. */
+}
+
+%code {
+  int yylex (YYSTYPE *yylval);
+  void yyerror (char const *);
+}
+
+%define api.header.include {"calc.h"}
+
+/* Generate YYSTYPE from the types used in %token and %type.  */
+%define api.value.type union
+%token <double> NUM "number"
+%type  <double> expr term fact
+
+/* Don't share global variables between the scanner and the parser.  */
+%define api.pure full
+/* Generate a push parser.  */
+%define api.push-pull push
+
+/* Nice error messages with details. */
+%define parse.error detailed
+
+/* Generate the parser description file (calc.output).  */
+%verbose
+
+ /* Enable run-time traces (yydebug).  */
+%define parse.trace
+
+/* Formatting semantic values in debug traces.  */
+%printer { fprintf (yyo, "%g", $$); } <double>;
+
+%% /* The grammar follows.  */
+input:
+  %empty
+| input line
+;
+
+line:
+  '\n'
+| expr '\n'  { printf ("%.10g\n", $1); }
+| error '\n' { yyerrok; }
+;
+
+expr:
+  expr '+' term { $$ = $1 + $3; }
+| expr '-' term { $$ = $1 - $3; }
+| term
+;
+
+term:
+  term '*' fact { $$ = $1 * $3; }
+| term '/' fact { $$ = $1 / $3; }
+| fact
+;
+
+fact:
+  "number"
+| '(' expr ')' { $$ = $expr; }
+;
+
+%%
+
+int
+yylex (YYSTYPE *yylval)
+{
+  int c;
+
+  /* Ignore white space, get first nonwhite character.  */
+  while ((c = getchar ()) == ' ' || c == '\t')
+    continue;
+
+  if (c == EOF)
+    return 0;
+
+  /* Char starts a number => parse the number.         */
+  if (c == '.' || isdigit (c))
+    {
+      ungetc (c, stdin);
+      if (scanf ("%lf", &yylval->NUM) != 1)
+        abort ();
+      return NUM;
+    }
+
+  /* Any other character is a token by itself.        */
+  return c;
+}
+
+/* Called by yyparse on error.  */
+void
+yyerror (char const *s)
+{
+  fprintf (stderr, "%s\n", s);
+}
+
+int
+main (int argc, char const* argv[])
+{
+  /* Enable parse traces on option -p.  */
+  for (int i = 1; i < argc; ++i)
+    if (!strcmp (argv[i], "-p"))
+      yydebug = 1;
+  int status;
+  yypstate *ps = yypstate_new ();
+  do {
+    YYSTYPE lval;
+    status = yypush_parse (ps, yylex (&lval), &lval);
+  } while (status == YYPUSH_MORE);
+  yypstate_delete (ps);
+  return status;
+}

local/recipes/dev/bison/source/examples/c/pushcalc/local.mk

@@ -0,0 +1,34 @@
+## Copyright (C) 2020-2021 Free Software Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+pushcalcdir = $(docdir)/%D%
+
+## ------ ##
+## Calc.  ##
+## ------ ##
+
+check_PROGRAMS += %D%/calc
+TESTS += %D%/calc.test
+EXTRA_DIST += %D%/calc.test
+nodist_%C%_calc_SOURCES = %D%/calc.y
+%D%/calc.c: $(dependencies)
+
+# Don't use gnulib's system headers.
+%C%_calc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_calc_CFLAGS = $(TEST_CFLAGS)
+
+dist_pushcalc_DATA = %D%/calc.y %D%/Makefile %D%/README.md
+CLEANFILES += %D%/calc.[ch] %D%/calc.output
+CLEANDIRS += %D%/*.dSYM

local/recipes/dev/bison/source/examples/c/reccalc/Makefile

@@ -0,0 +1,30 @@
+# This Makefile is designed to be simple and readable.  It does not
+# aim at portability.  It requires GNU Make.
+
+BASE = reccalc
+BISON = bison
+FLEX = flex
+
+all: $(BASE)
+
+%.c %.h %.xml %.gv: %.y
+	$(BISON) $(BISONFLAGS) --header --graph -o $*.c $<
+
+%.c %.h: %.l
+	$(FLEX) $(FLEXFLAGS) -o$*.c --header=$*.h $<
+
+scan.o: parse.h
+parse.o: scan.h
+$(BASE): parse.o scan.o
+	$(CC) $(CFLAGS) -o $@ $^
+
+run: $(BASE)
+	@echo "Type arithmetic expressions.  Quit with ctrl-d."
+	./$<
+
+CLEANFILES =						\
+  $(BASE) *.o						\
+  parse.[ch] parse.output parse.xml parse.html parse.gv	\
+  scan.[ch]
+clean:
+	rm -f $(CLEANFILES)

local/recipes/dev/bison/source/examples/c/reccalc/README.md

@@ -0,0 +1,38 @@
+# reccalc - recursive calculator with Flex and Bison
+
+In this example the generated parser is pure and reentrant: it can be used
+concurrently in different threads, or recursively.  As a proof of this
+reentrancy, expressions in parenthesis are tokenized as strings, and then
+recursively parsed from the parser:
+
+```
+exp: STR
+  {
+    result r = parse_string ($1);
+    free ($1);
+    if (r.nerrs)
+      {
+        res->nerrs += r.nerrs;
+        YYERROR;
+      }
+    else
+      $$ = r.value;
+  }
+```
+
+<!---
+Local Variables:
+fill-column: 76
+ispell-dictionary: "american"
+End:
+
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts.  A copy of the license is included in the "GNU Free
+Documentation License" file as part of this distribution.
+
+--->

local/recipes/dev/bison/source/examples/c/reccalc/local.mk

@@ -0,0 +1,83 @@
+## Copyright (C) 2019-2021 Free Software Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+reccalcdir = $(docdir)/%D%
+
+## --------- ##
+## RecCalc.  ##
+## --------- ##
+
+if FLEX_WORKS
+  check_PROGRAMS += %D%/reccalc
+  TESTS += %D%/reccalc.test
+  nodist_%C%_reccalc_SOURCES = %D%/parse.y %D%/scan.h %D%/scan.c
+  BUILT_SOURCES += $(nodist_%C%_reccalc_SOURCES)
+  # Don't use gnulib's system headers.
+  %C%_reccalc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+  # Fighting warnings triggered by Flex is just too painful.
+  # %C%_reccalc_CFLAGS = $(TEST_CFLAGS)
+endif FLEX_WORKS
+
+%D%/parse.c: $(dependencies)
+
+# Tell Make that parse.o depends on scan.h, so that scan.h is built
+# before parse.o.  Obfuscate the name of the target, otherwise
+# Automake removes its recipe for parse.o and leaves only our
+# additional dependency.
+DASH = -
+%D%/reccalc$(DASH)parse.o: %D%/scan.h
+# Tell Make scan.o depends on parse.h, except that Make sees only
+# parse.c, not parse.h.  We can't use BUILT_SOURCES to this end, since
+# we use the built bison.
+%D%/reccalc$(DASH)scan.o: %D%/parse.c
+
+# Likewise, but for Automake before 1.16.
+%D%/examples_c_reccalc_reccalc$(DASH)parse.o: %D%/scan.h
+%D%/examples_c_reccalc_reccalc$(DASH)scan.o: %D%/parse.c
+
+## See "info automake 'Multiple Outputs'" for this rule.
+%D%/scan.c %D%/scan.h: %D%/scan.stamp
+## Recover from the removal of $@
+	@if test -f $@; then :; else \
+	  trap 'rm -rf %D%/scan.lock %D%/scan.stamp' 1 2 13 15; \
+## mkdir is a portable test-and-set
+	  if mkdir %D%/scan.lock 2>/dev/null; then \
+## This code is being executed by the first process.
+	    rm -f %D%/scan.stamp; \
+	    $(MAKE) $(AM_MAKEFLAGS) %D%/scan.stamp; \
+	    result=$$?; rm -rf %D%/scan.lock; exit $$result; \
+	  else \
+## This code is being executed by the follower processes.
+## Wait until the first process is done.
+	    while test -d %D%/scan.lock; do sleep 1; done; \
+## Succeed if and only if the first process succeeded.
+	    test -f %D%/scan.stamp; \
+	  fi; \
+	fi
+
+%D%/scan.stamp: %D%/scan.l
+	$(AM_V_LEX)rm -f $@ $@.tmp
+	$(AM_V_at)$(MKDIR_P) %D%
+	$(AM_V_at)touch $@.tmp
+## --header introduced in 2.5.6, renamed as --header-file in 2.6.4.
+## Backward compatibility ensured since --header is an unambiguous prefix.
+	$(AM_V_at)$(LEX) $(AM_LFLAGS) $(LFLAGS) -o%D%/scan.c --header=%D%/scan.h $(srcdir)/%D%/scan.l
+	$(AM_V_at)mv $@.tmp $@
+
+
+EXTRA_DIST += %D%/reccalc.test %D%/scan.l
+dist_reccalc_DATA = %D%/parse.y %D%/scan.l %D%/Makefile %D%/README.md
+CLEANFILES += %D%/parse.[ch] %D%/parse.output %D%/scan.[ch] %D%/*.stamp
+CLEANDIRS += %D%/*.dSYM

local/recipes/dev/bison/source/examples/c/reccalc/parse.y

@@ -0,0 +1,220 @@
+/* Parser for reccalc.   -*- C -*-
+
+   Copyright (C) 2019-2021 Free Software Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+// Prologue (directives).
+%expect 0
+
+// Emitted in the header file, before the definition of YYSTYPE.
+%code requires
+{
+  #ifndef YY_TYPEDEF_YY_SCANNER_T
+  # define YY_TYPEDEF_YY_SCANNER_T
+  typedef void* yyscan_t;
+  #endif
+
+  typedef struct
+  {
+    // Whether to print the intermediate results.
+    int verbose;
+    // Value of the last computation.
+    int value;
+    // Number of errors.
+    int nerrs;
+  } result;
+}
+
+// Emitted in the header file, after the definition of YYSTYPE.
+%code provides
+{
+  // Tell Flex the expected prototype of yylex.
+  // The scanner argument must be named yyscanner.
+#define YY_DECL                                                         \
+  yytoken_kind_t yylex (YYSTYPE* yylval, yyscan_t yyscanner, result *res)
+  YY_DECL;
+
+  void yyerror (yyscan_t scanner, result *res, const char *msg, ...);
+}
+
+// Emitted on top of the implementation file.
+%code top
+{
+#include <stdarg.h> // va_list.
+#include <stdio.h>  // printf.
+#include <stdlib.h> // getenv.
+}
+
+%code
+{
+  result parse_string (const char* cp);
+  result parse (void);
+}
+
+// Include the header in the implementation rather than duplicating it.
+%define api.header.include {"parse.h"}
+
+// Don't share global variables between the scanner and the parser.
+%define api.pure full
+
+// To avoid name clashes (e.g., with C's EOF) prefix token definitions
+// with TOK_ (e.g., TOK_EOF).
+%define api.token.prefix {TOK_}
+
+// Generate YYSTYPE from the types assigned to symbols.
+%define api.value.type union
+
+// Error messages with "unexpected XXX, expected XXX...".
+%define parse.error detailed
+
+// Enable run-time traces (yydebug).
+%define parse.trace
+
+// Generate the parser description file (parse.output).
+%verbose
+
+// Scanner and error count are exchanged between main, yyparse and yylex.
+%param {yyscan_t scanner}{result *res}
+
+%token
+  PLUS   "+"
+  MINUS  "-"
+  STAR   "*"
+  SLASH  "/"
+  EOL    "end-of-line"
+  EOF 0  "end-of-file"
+;
+
+%token <int> NUM "number"
+%type <int> exp
+%printer { fprintf (yyo, "%d", $$); } <int>
+
+%token <char*> STR "string"
+%printer { fprintf (yyo, "\"%s\"", $$); } <char*>
+%destructor { free ($$); } <char*>
+
+// Precedence (from lowest to highest) and associativity.
+%left "+" "-"
+%left "*" "/"
+%precedence UNARY
+
+%%
+// Rules.
+input:
+  line
+| input line
+;
+
+line:
+  exp eol
+    {
+      res->value = $exp;
+      if (res->verbose)
+        printf ("%d\n", $exp);
+    }
+| error eol
+    {
+      yyerrok;
+    }
+;
+
+eol:
+  EOF
+| EOL
+;
+
+exp:
+  NUM           { $$ = $1; }
+| exp "+" exp   { $$ = $1 + $3; }
+| exp "-" exp   { $$ = $1 - $3; }
+| exp "*" exp   { $$ = $1 * $3; }
+| exp "/" exp
+  {
+    if ($3 == 0)
+      {
+        yyerror (scanner, res, "invalid division by zero");
+        YYERROR;
+      }
+    else
+      $$ = $1 / $3;
+  }
+| "+" exp %prec UNARY  { $$ = + $2; }
+| "-" exp %prec UNARY  { $$ = - $2; }
+| STR
+  {
+    result r = parse_string ($1);
+    free ($1);
+    if (r.nerrs)
+      {
+        res->nerrs += r.nerrs;
+        YYERROR;
+      }
+    else
+      $$ = r.value;
+  }
+;
+
+%%
+// Epilogue (C code).
+#include "scan.h"
+
+result
+parse (void)
+{
+  yyscan_t scanner;
+  yylex_init (&scanner);
+  result res = {1, 0, 0};
+  yyparse (scanner, &res);
+  yylex_destroy (scanner);
+  return res;
+}
+
+result
+parse_string (const char *str)
+{
+  yyscan_t scanner;
+  yylex_init (&scanner);
+  YY_BUFFER_STATE buf = yy_scan_string (str ? str : "", scanner);
+  result res = {0, 0, 0};
+  yyparse (scanner, &res);
+  yy_delete_buffer (buf, scanner);
+  yylex_destroy (scanner);
+  return res;
+}
+
+void
+yyerror (yyscan_t scanner, result *res,
+         const char *msg, ...)
+{
+  (void) scanner;
+  va_list args;
+  va_start (args, msg);
+  vfprintf (stderr, msg, args);
+  va_end (args);
+  fputc ('\n', stderr);
+  res->nerrs += 1;
+}
+
+int
+main (void)
+{
+  // Possibly enable parser runtime debugging.
+  yydebug = !!getenv ("YYDEBUG");
+  result res = parse ();
+  // Exit on failure if there were errors.
+  return !!res.nerrs;
+}

local/recipes/dev/bison/source/examples/c/reccalc/reccalc.test

@@ -0,0 +1,59 @@
+#! /bin/sh
+
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+(seq 0) >/dev/null 2>&1 || skip "gimme one seq"
+
+cat >input <<EOF
+1+2*3
+EOF
+run 0 '7'
+
+cat >input <<EOF
+(1+2) * 3
+EOF
+run 0 '9'
+run -noerr 0 '9' -p
+
+cat >input <<EOF
+(((1)+(2))*((3)+(4)))
+EOF
+run 0 '21'
+
+# Some really deep computation.
+# for 4, gives 4 + (3 + (2 + (1 + (- (4 * (4 + 1)) / 2)))).
+n=100
+for i in $(seq 0 $n)
+do
+    if [ "$i" -eq 0 ]; then
+        input="- ($n * ($n + 1)) / 2"
+    else
+        input="$i + ($input)"
+    fi
+done
+echo "$input" > input
+run 0 '0'
+
+cat >input <<EOF
+() + ()
+EOF
+run 1 'err: syntax error, unexpected end-of-file, expecting + or - or number or string'
+
+cat >input <<EOF
+1 + $
+EOF
+run 1 'err: syntax error, invalid character: $
+err: syntax error, unexpected end-of-line, expecting + or - or number or string'

local/recipes/dev/bison/source/examples/c/reccalc/scan.l

@@ -0,0 +1,108 @@
+/* Scanner for reccalc.   -*- C -*-
+
+   Copyright (C) 2019-2021 Free Software Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Prologue (directives).   -*- C -*- */
+
+/* Disable Flex features we don't need, to avoid warnings. */
+%option nodefault noinput nounput noyywrap
+
+%option reentrant
+
+%{
+#include <assert.h>
+#include <limits.h> /* INT_MIN */
+#include <stdlib.h> /* strtol */
+
+#include "parse.h"
+%}
+
+%x SC_STRING
+
+%%
+%{
+  // Number of opened parentheses.
+  int nesting = 0;
+  // A buffer storing the text inside the outer parentheses.
+  char *str = NULL;
+  // Its allocated size.
+  int capacity = 0;
+  // Its used size.
+  int size = 0;
+#define STR_APPEND()                                    \
+  do {                                                  \
+    if (capacity < size + yyleng + 1)                   \
+      {                                                 \
+        do                                              \
+          capacity = capacity ? 2 * capacity : 128;     \
+        while (capacity < size + yyleng + 1);           \
+        str = realloc (str, (size_t) capacity);         \
+      }                                                 \
+    memcpy (str + size, yytext, (size_t) yyleng);       \
+    size += yyleng;                                     \
+    assert (size < capacity);                           \
+  } while (0)
+%}
+
+ // Rules.
+
+"+"      return TOK_PLUS;
+"-"      return TOK_MINUS;
+"*"      return TOK_STAR;
+"/"      return TOK_SLASH;
+
+"("      nesting += 1; BEGIN SC_STRING;
+
+ /* Scan an integer.  */
+[0-9]+   {
+  errno = 0;
+  long n = strtol (yytext, NULL, 10);
+  if (! (INT_MIN <= n && n <= INT_MAX && errno != ERANGE))
+    yyerror (yyscanner, res, "integer is out of range");
+  yylval->TOK_NUM = (int) n;
+  return TOK_NUM;
+}
+
+ /* Ignore white spaces. */
+[ \t]+   continue;
+
+"\n"     return TOK_EOL;
+
+.        yyerror (yyscanner, res, "syntax error, invalid character: %c", yytext[0]);
+
+<SC_STRING>
+{
+  "("+   nesting += yyleng; STR_APPEND ();
+  ")"    {
+    if (!--nesting)
+      {
+        BEGIN INITIAL;
+        if (str)
+          str[size] = 0;
+        yylval->TOK_STR = str;
+        return TOK_STR;
+      }
+    else
+      STR_APPEND ();
+  }
+  [^()]+  STR_APPEND ();
+}
+
+<<EOF>>  return TOK_EOF;
+%%
+/* Epilogue (C code). */

local/recipes/dev/bison/source/examples/c/rpcalc/Makefile

@@ -0,0 +1,20 @@
+# This Makefile is designed to be simple and readable.  It does not
+# aim at portability.  It requires GNU Make.
+
+BASE = rpcalc
+BISON = bison
+
+all: $(BASE)
+
+%.c %.html %.gv: %.y
+	$(BISON) $(BISONFLAGS) --html --graph -o $*.c $<
+
+%: %.c
+	$(CC) $(CFLAGS) -o $@ $<
+
+run: $(BASE)
+	@echo "Type arithmetic expressions in Reverse Polish Notation.  Quit with ctrl-d."
+	./$<
+
+clean:
+	rm -f $(BASE) $(BASE).c $(BASE).html $(BASE).xml $(BASE).gv

local/recipes/dev/bison/source/examples/c/rpcalc/local.mk

@@ -0,0 +1,45 @@
+## Copyright (C) 2005-2006, 2008-2015, 2018-2021 Free Software
+## Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+## -------------------- ##
+## Building & testing.  ##
+## -------------------- ##
+
+BUILT_SOURCES += $(rpcalc_sources)
+CLEANFILES +=  %D%/rpcalc.[ch] %D%/rpcalc.output
+CLEANDIRS += %D%/*.dSYM
+
+rpcalc_extracted = %D%/rpcalc.y
+rpcalc_sources = $(rpcalc_extracted)
+extracted += $(rpcalc_extracted)
+
+check_PROGRAMS += %D%/rpcalc
+nodist_%C%_rpcalc_SOURCES = $(rpcalc_sources)
+%D%/rpcalc.c: $(dependencies)
+# Don't use gnulib's system headers.
+%C%_rpcalc_CPPFLAGS = -I$(top_builddir)/%D%
+%C%_rpcalc_CFLAGS = $(TEST_CFLAGS)
+%C%_rpcalc_LDADD = -lm
+
+dist_TESTS += %D%/rpcalc.test
+
+## ------------ ##
+## Installing.  ##
+## ------------ ##
+
+rpcalcdir = $(docdir)/%D%
+rpcalc_DATA = $(rpcalc_extracted)
+dist_rpcalc_DATA = %D%/Makefile

local/recipes/dev/bison/source/examples/c/rpcalc/rpcalc.test

@@ -0,0 +1,46 @@
+#! /bin/sh
+
+# Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+cat >input <<EOF
+1 2 3 * +
+EOF
+run 0 7
+
+cat >input <<EOF
+1.1 2.2 3.3 * +
+EOF
+run 0 8.36
+
+cat >input <<EOF
+1 2 + 3 *
+EOF
+run 0 9
+
+cat >input <<EOF
+1 2 3 4 5 6 7 8 9 * * * * * * * *
+EOF
+run 0 362880
+
+cat >input <<EOF
+3 7 + 3 4 5 * + - n
+EOF
+run 0 13
+
+cat >input <<EOF
+3 4 ^
+EOF
+run 0 81

local/recipes/dev/bison/source/examples/c/rpcalc/rpcalc.y

@@ -0,0 +1,100 @@
+/* Parser for rpcalc.   -*- C -*-
+
+   Copyright (C) 1988-1993, 1995, 1998-2015, 2018-2021 Free Software
+   Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Reverse Polish Notation calculator. */
+
+%{
+  #include <stdio.h>
+  #include <math.h>
+  int yylex (void);
+  void yyerror (char const *);
+%}
+
+%define api.value.type {double}
+%token NUM
+
+%% /* Grammar rules and actions follow. */
+
+input:
+  %empty
+| input line
+;
+
+line:
+  '\n'
+| exp '\n'      { printf ("%.10g\n", $1); }
+;
+
+exp:
+  NUM
+| exp exp '+'   { $$ = $1 + $2;      }
+| exp exp '-'   { $$ = $1 - $2;      }
+| exp exp '*'   { $$ = $1 * $2;      }
+| exp exp '/'   { $$ = $1 / $2;      }
+| exp exp '^'   { $$ = pow ($1, $2); }  /* Exponentiation */
+| exp 'n'       { $$ = -$1;          }  /* Unary minus   */
+;
+%%
+
+/* The lexical analyzer returns a double floating point
+   number on the stack and the token NUM, or the numeric code
+   of the character read if not a number.  It skips all blanks
+   and tabs, and returns 0 for end-of-input. */
+
+#include <ctype.h>
+#include <stdlib.h>
+
+int
+yylex (void)
+{
+  int c = getchar ();
+  /* Skip white space. */
+  while (c == ' ' || c == '\t')
+    c = getchar ();
+  /* Process numbers. */
+  if (c == '.' || isdigit (c))
+    {
+      ungetc (c, stdin);
+      if (scanf ("%lf", &yylval) != 1)
+        abort ();
+      return NUM;
+    }
+  /* Return end-of-input. */
+  else if (c == EOF)
+    return YYEOF;
+  /* Return a single char. */
+  else
+    return c;
+}
+
+int
+main (void)
+{
+  return yyparse ();
+}
+
+#include <stdio.h>
+
+/* Called by yyparse on error. */
+void
+yyerror (char const *s)
+{
+  fprintf (stderr, "%s\n", s);
+}