Allow builtin text macros to specify number of arguments.

* m4/m4module.h (struct m4_macro): Add argument limits to builtin
text macros.
* m4/module.c (install_macro_table): Allow text macros to warn on
extra arguments.
* modules/gnu.c (m4_macro_table): Update all clients.
* modules/load.c (m4_macro_table): Likewise.
* modules/mpeval.c (m4_macro_table): Likewise.
* modules/perl.c (m4_macro_table): Likewise.
* modules/shadow.c (m4_macro_table): Likewise.
* modules/traditional.c (m4_macro_table): Likewise.
* modules/modtest.c (m4_macro_table): Likewise.  Also add text
macros, for testing this.
* doc/m4.texinfo (Standard Modules): Update text, and enhance
test.
* tests/modules.at (modules: text): New test.

Signed-off-by: Eric Blake <ebb9@byu.net>

12 files changed, 129 insertions, 39 deletions

diff --git a/ChangeLog b/ChangeLog
index d9b01756..2554a450 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,22 @@
 2008-02-11  Eric Blake  <ebb9@byu.net>
 
+	Allow builtin text macros to specify number of arguments.
+	* m4/m4module.h (struct m4_macro): Add argument limits to builtin
+	text macros.
+	* m4/module.c (install_macro_table): Allow text macros to warn on
+	extra arguments.
+	* modules/gnu.c (m4_macro_table): Update all clients.
+	* modules/load.c (m4_macro_table): Likewise.
+	* modules/mpeval.c (m4_macro_table): Likewise.
+	* modules/perl.c (m4_macro_table): Likewise.
+	* modules/shadow.c (m4_macro_table): Likewise.
+	* modules/traditional.c (m4_macro_table): Likewise.
+	* modules/modtest.c (m4_macro_table): Likewise.  Also add text
+	macros, for testing this.
+	* doc/m4.texinfo (Standard Modules): Update text, and enhance
+	test.
+	* tests/modules.at (modules: text): New test.
+
 	Fix regression in command line -D option, from 2006-08-25.
 	* m4/m4private.h (m4_symbol_value_create): Delete fast accessor.
 	* m4/m4module.h: Fix typo.
diff --git a/doc/m4.texinfo b/doc/m4.texinfo
index 642c14eb..357358ff 100644
--- a/doc/m4.texinfo
+++ b/doc/m4.texinfo
@@ -5804,7 +5804,9 @@ refcount(`NoSuchModule')
 @acronym{GNU} @code{m4} ships with several bundled modules as standard.
 By convention, these modules define a text macro that can be tested
 with @code{ifdef} when they are loaded; only the @code{m4} module lacks
-this feature test macro.
+this feature test macro, since it is not permitted by @acronym{POSIX}.
+Each of the feature test macros are intended to be used without
+arguments.
 
 @table @code
 @item m4
@@ -5823,8 +5825,8 @@ module is loaded.
 @end deffn
 
 @deffn {Macro (gnu)} __m4_version__
-Expands to a quoted string containing the release version number of the
-running @acronym{GNU} @code{m4} executable.
+Expands to an unquoted string containing the release version number of
+the running @acronym{GNU} @code{m4} executable.
 @end deffn
 
 This module is always loaded, unless the @option{-G} command line
@@ -5871,6 +5873,9 @@ __gnu__-__traditional__
 @result{}-__traditional__
 ifdef(`__gnu__', `Extensions are active', `Minimal features')
 @result{}Extensions are active
+__gnu__(`ignored')
+@error{}m4:stdin:3: Warning: __gnu__: extra arguments ignored: 1 > 0
+@result{}
 @end example
 
 @comment options: -G
@@ -5882,6 +5887,19 @@ ifdef(`__gnu__', `Extensions are active', `Minimal features')
 @result{}Minimal features
 @end example
 
+Since the version string is unquoted and can potentially contain macro
+names (consider the beta release @samp{1.9b}, or the use of
+@code{changesyntax}), the @code{__m4_version__} macro should generally
+be used via @code{defn} rather than directly invoked.
+
+@comment This test is excluded from the testsuite since it depends on a
+@comment texinfo macro; but builtin.at covers the same thing.
+@comment ignore
+@example
+defn(`__m4_version__')
+@result{}@value{VERSION}
+@end example
+
 @node Text handling
 @chapter Macros for text handling
 
diff --git a/m4/m4module.h b/m4/m4module.h
index 5f144be2..a807e70b 100644
--- a/m4/m4module.h
+++ b/m4/m4module.h
@@ -75,6 +75,9 @@ struct m4_macro
 {
   const char *name;
   const char *value;
+  size_t      min_args; /* 0-based minimum number of arguments */
+  /* max arguments, SIZE_MAX if unlimited; must be >= min_args */
+  size_t      max_args;
 };
 
 /* Describe a pair of strings, such as begin and end quotes.  */
diff --git a/m4/module.c b/m4/module.c
index 901a48f7..7ef6ab32 100644
--- a/m4/module.c
+++ b/m4/module.c
@@ -1,6 +1,6 @@
 /* GNU m4 -- A simple macro processor
    Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 1998, 1999, 2002, 2003,
-   2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+   2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
 
    This file is part of GNU M4.
 
@@ -195,9 +195,14 @@ install_macro_table (m4 *context, m4_module *module)
 	  m4_symbol_value *value = m4_symbol_value_create ();
 	  size_t len = strlen (mp->value);
 
+	  /* Sanity check that builtins meet the required interface.  */
+	  assert (mp->min_args <= mp->max_args);
+
 	  m4_set_symbol_value_text (value, xmemdup (mp->value, len + 1),
                                     len, 0);
 	  VALUE_MODULE (value) = module;
+	  VALUE_MIN_ARGS (value) = mp->min_args;
+	  VALUE_MAX_ARGS (value) = mp->max_args;
 
 	  m4_symbol_pushdef (M4SYMTAB, mp->name, value);
 	}
diff --git a/modules/gnu.c b/modules/gnu.c
index 1f6bf299..10fb0acb 100644
--- a/modules/gnu.c
+++ b/modules/gnu.c
@@ -85,20 +85,20 @@ m4_builtin m4_builtin_table[] =
 /* A table for mapping m4 symbol names to simple expansion text. */
 m4_macro m4_macro_table[] =
 {
-  /* name		text */
+  /* name		text	min	max */
 #if UNIX
-  { "__unix__",		"" },
+  { "__unix__",		"",	0,	0 },
 #elif W32_NATIVE
-  { "__windows__",	"" },
+  { "__windows__",	"",	0,	0 },
 #elif OS2
-  { "__os2__",		"" },
+  { "__os2__",		"",	0,	0 },
 #else
 # warning Platform macro not provided
 #endif
-  { "__gnu__",		"" },
-  { "__m4_version__",	VERSION/**/TIMESTAMP },
+  { "__gnu__",		"",	0,	0 },
+  { "__m4_version__",	VERSION/**/TIMESTAMP, 0, 0 },
 
-  { NULL, NULL },
+  { NULL,		NULL,	0,	0 },
 };
 
 
diff --git a/modules/load.c b/modules/load.c
index 4ee1cc62..5ea72424 100644
--- a/modules/load.c
+++ b/modules/load.c
@@ -1,5 +1,6 @@
 /* GNU m4 -- A simple macro processor
-   Copyright (C) 2000, 2005, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 2000, 2005, 2006, 2007, 2008 Free Software
+   Foundation, Inc.
 
    This file is part of GNU M4.
 
@@ -65,9 +66,9 @@ m4_builtin m4_builtin_table[] =
 /* A table for mapping m4 symbol names to simple expansion text. */
 m4_macro m4_macro_table[] =
 {
-  /* name		text */
-  { "__load__",		"" },
-  { NULL,		NULL },
+  /* name		text	min	max */
+  { "__load__",		"",	0,	0 },
+  { NULL,		NULL,	0,	0 },
 };
 
 
diff --git a/modules/modtest.c b/modules/modtest.c
index 022a2efa..f2d39eac 100644
--- a/modules/modtest.c
+++ b/modules/modtest.c
@@ -1,6 +1,6 @@
 /* GNU m4 -- A simple macro processor
-   Copyright (C) 1999, 2000, 2001, 2003, 2004, 2006, 2007 Free Software
-   Foundation, Inc.
+   Copyright (C) 1999, 2000, 2001, 2003, 2004, 2006, 2007, 2008 Free
+   Software Foundation, Inc.
 
    This file is part of GNU M4.
 
@@ -61,9 +61,11 @@ m4_builtin m4_builtin_table[] =
 
 m4_macro m4_macro_table[] =
 {
-  /* name		text */
-  { "__test__",		"`modtest'" },
-  { NULL,		NULL },
+  /* name		text		min	max */
+  { "__test__",		"`modtest'",	0,	0 },
+  { "onearg",		"$1",		1,	1 },
+  { "manyargs",		"$@",		0,	SIZE_MAX },
+  { NULL,		NULL,		0,	0 },
 };
 
 
diff --git a/modules/mpeval.c b/modules/mpeval.c
index e70eb091..ab9a040f 100644
--- a/modules/mpeval.c
+++ b/modules/mpeval.c
@@ -1,5 +1,6 @@
 /* GNU m4 -- A simple macro processor
-   Copyright (C) 2000, 2001, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 2000, 2001, 2006, 2007, 2008 Free Software
+   Foundation, Inc.
 
    This file is part of GNU M4.
 
@@ -123,9 +124,9 @@ m4_builtin m4_builtin_table[] =
 /* A table for mapping m4 symbol names to simple expansion text. */
 m4_macro m4_macro_table[] =
 {
-  /* name		text */
-  { "__mpeval__",	"" },
-  { NULL,		NULL },
+  /* name		text	min	max */
+  { "__mpeval__",	"",	0,	0 },
+  { NULL,		NULL,	0,	0 },
 };
 
 
diff --git a/modules/perl.c b/modules/perl.c
index 46cf2cde..61db8032 100644
--- a/modules/perl.c
+++ b/modules/perl.c
@@ -64,9 +64,9 @@ m4_builtin m4_builtin_table[] =
 /* A table for mapping m4 symbol names to simple expansion text. */
 m4_macro m4_macro_table[] =
 {
-  /* name			text */
-  { "__perleval__",		"" },
-  { NULL, NULL },
+  /* name		text	min	max */
+  { "__perleval__",	"",	0,	0 },
+  { NULL,		NULL,	0,	0 },
 };
 
 
diff --git a/modules/shadow.c b/modules/shadow.c
index 3698b4f0..1a15798f 100644
--- a/modules/shadow.c
+++ b/modules/shadow.c
@@ -1,5 +1,6 @@
 /* GNU m4 -- A simple macro processor
-   Copyright (C) 1999, 2000, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2000, 2006, 2007, 2008 Free Software
+   Foundation, Inc.
 
    This file is part of GNU M4.
 
@@ -58,9 +59,9 @@ m4_builtin m4_builtin_table[] =
 
 m4_macro m4_macro_table[] =
 {
-  /* name		text */
-  { "__test__",		"`shadow'" },
-  { NULL, NULL },
+  /* name		text		min	max */
+  { "__test__",		"`shadow'",	0,	0 },
+  { NULL,		NULL,		0,	0 },
 };
 
 
diff --git a/modules/traditional.c b/modules/traditional.c
index 9fc2e818..13a112d2 100644
--- a/modules/traditional.c
+++ b/modules/traditional.c
@@ -1,5 +1,5 @@
 /* GNU m4 -- A simple macro processor
-   Copyright (C) 2000, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 2000, 2006, 2007, 2008 Free Software Foundation, Inc.
 
    This file is part of GNU M4.
 
@@ -33,16 +33,16 @@
 /* A table for mapping m4 symbol names to simple expansion text. */
 m4_macro m4_macro_table[] =
 {
-  /* name		text */
+  /* name		text	min	max */
 #if UNIX
-  { "unix",		"" },
+  { "unix",		"",	0,	0 },
 #elif W32_NATIVE
-  { "windows",		"" },
+  { "windows",		"",	0,	0 },
 #elif OS2
-  { "os2",		"" },
+  { "os2",		"",	0,	0 },
 #else
 # warning Platform macro not provided
 #endif
-  { "__traditional__",	"" },
-  { NULL,		NULL },
+  { "__traditional__",	"",	0,	0 },
+  { NULL,		NULL,	0,	0 },
 };
diff --git a/tests/modules.at b/tests/modules.at
index 86f13888..0d818481 100644
--- a/tests/modules.at
+++ b/tests/modules.at
@@ -1,5 +1,5 @@
 # Hand crafted tests for GNU M4.                               -*- Autotest -*-
-# Copyright (C) 2001, 2006, 2007 Free Software Foundation, Inc.
+# Copyright (C) 2001, 2006, 2007, 2008 Free Software Foundation, Inc.
 
 # This file is part of GNU M4.
 #
@@ -422,6 +422,48 @@ AT_CLEANUP
 
 
 
+## ------------------- ##
+## text module symbols ##
+## ------------------- ##
+
+# Support text macros with requested numbers of parameters.
+
+AT_SETUP([modules: text])
+AT_CHECK_DYNAMIC_MODULE
+
+AT_DATA([input.m4],
+[[__test__
+__test__(1)
+__test__(1,2)
+onearg
+onearg(1)
+onearg(1,2)
+manyargs
+manyargs(1)
+manyargs(1,2)
+]])
+
+AT_CHECK_M4([-M "$abs_builddir" -m modtest input.m4], [0],
+[[modtest
+modtest
+modtest
+
+1
+1
+
+1
+1,2
+]], [[Test module loaded.
+m4:input.m4:2: Warning: __test__: extra arguments ignored: 1 > 0
+m4:input.m4:3: Warning: __test__: extra arguments ignored: 2 > 0
+m4:input.m4:4: Warning: onearg: too few arguments: 0 < 1
+m4:input.m4:6: Warning: onearg: extra arguments ignored: 2 > 1
+Test module unloaded.
+]])
+
+AT_CLEANUP
+
+
 ## -------------------- ##
 ## trace module symbols ##
 ## -------------------- ##