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Re: POSIX behavior of eval
|
From: |
Eric Blake |
|
Subject: |
Re: POSIX behavior of eval |
|
Date: |
Wed, 28 Feb 2007 21:30:46 +0000 (UTC) |
|
User-agent: |
Loom/3.14 (http://gmane.org/) |
Eric Blake <ebb9 <at> byu.net> writes:
> The Austin Group approved XCU ERN 118:
They also approved XCU ERN 137. This patch has some code cleanups that I
noticed while implementing ${1} semantics and porting --warn-macro-sequence
from the branch, I'm committing this to reduce the size of that patch. main.c
is listed in diff -b, since I changed some indenting.
2007-02-28 Eric Blake <address@hidden>
POSIX XCU ERN 137 was approved.
* modules/mpeval.c (numb_extension): Delete.
* modules/m4.c (numb_extension): Likewise.
* modules/evalparse.c (comma_term, condition_term): Always
implement ?: and , operators.
* m4/symtab.c: Update comment to match reality.
* src/freeze.c (produce_frozen_state, reload_frozen_state): Avoid
dereferencing context directly when accessor exists.
* src/main.c (usage): Prefer GNU_M4 over EMACS.
(struct macro_definition): Rename...
(struct deferred): ...to match usage. All uses changed.
* doc/m4.texinfo (Eval): Document this change.
(Operation modes, Changeresyntax): Fix wording to prefer GNU_M4
over emacs.
(Preprocessor features, Changesyntax): Fix inaccuracies.
* NEWS: Import branch NEWS items for 1.4.x series. Document
change in eval.
Index: NEWS
===================================================================
RCS file: /sources/m4/m4/NEWS,v
retrieving revision 1.39
diff -u -r1.39 NEWS
--- NEWS 28 Feb 2007 14:36:22 -0000 1.39
+++ NEWS 28 Feb 2007 21:24:37 -0000
@@ -103,12 +103,12 @@
regular expression flavor, to match `-r'/`--regexp-syntax' command-line
option.
-*** New `debuglen' builtin is introduced which allows runtime setting of
- debug output length, previously controlled only by the `-l' command
- line argument. Additionally, whether using the new macro or the
- command line argument, the length limitation now affects dumpdef output
- as well as trace output, undergoes argument validation, and accepts an
- optional multiplier suffix.
+*** New `debuglen' builtin allows runtime setting of debug output length,
+ previously controlled only by the `-l' command line argument.
+ Additionally, whether using the new macro or the command line argument,
+ the length limitation now affects dumpdef output as well as trace
+ output, undergoes argument validation, and accepts an optional
+ multiplier suffix.
- FIXME the multiplier suffix isn't reliable yet
*** New `mkdtemp' builtin parallels `mkstemp', but allows the creation of
@@ -162,8 +162,7 @@
macro.
*** The `eval' and `mpeval' builtins now support the following new
- operators: `>>>', `\', `?:', and `,'. However, when complying
- strictly with POSIX, `?:' and `,' are rejected inside `eval'.
+ operators: `>>>', `\', `?:', and `,'.
*** The `maketemp' builtin now always warns that it is obsolete, even in GNU
mode where it uses the same secure algorithm as `mkstemp', because of
@@ -192,13 +191,329 @@
- FIXME: format 2 still needs to catch more missing state; once 2.0 is
released, any further changes would introduce format 3.
-FIXME: include the (long) list of changes in 1.4.x that were not already
- in earlier betas.
-* Version 1.4.9
-* Version 1.4.8
-* Version 1.4.7
-* Version 1.4.6
-* Version 1.4.5
+*** Improvements made in the 1.4.x stable series have been incorporated.
+
+* Version 1.4.9 - ?? ??? 2007, by ??? (CVS version 1.4.8c)
+
+** Minor documentation and portability cleanups.
+
+* Version 1.4.8b - 24 Feb 2007, by Eric Blake (CVS version 1.4.8a)
+
+** Fix a regression introduced in 1.4.8 that made m4 unable to process
+ files larger than 2GiB on some platforms.
+
+** Fix a regression introduced in 1.4.8 that made m4 dump core when
+ invoked as 'm4 -- file'.
+
+** The `eval' builtin now follows C precedence rules. Additionally, the
+ short-circuit operators correctly short-circuit division by zero. The
+ previously undocumented alias of '=' meaning '==' in eval now triggers a
+ deprecation warning, so that a future version of M4 can implement a form
+ of variable assignment as an extension.
+
+** The `include' builtin now affects exit status on failure, as required by
+ POSIX. Use `sinclude' if you need a successful exit status.
+
+** The `-E'/`--fatal-warnings' command-line option now has two levels. When
+ specified only once, warnings affect exit status, but execution
+ continues, so that you can see all warnings instead of fixing them one
+ at a time. To acheive 1.4.8 behavior, where the first warning
+ immediately exits, specify -E twice on the command line.
+
+** A new `--warn-macro-sequence' command-line option allows detection of
+ sequences in `define' and `pushdef' definitions that match an optional
+ regular expression. The default regular expression is
+ `\$\({[^}]*}\|[0-9][0-9]+\)', corresponding to the sequences that might
+ not behave correctly when upgrading to the eventual M4 2.0. By default,
+ M4 2.0 will follow the POSIX requirement that a macro definition
+ containing `$11' must expand to the first argument concatenated with 1,
+ rather than the eleventh argument; and will take advantage of the POSIX
+ wording that allows implementations to treat `${11}' as the eleventh
+ argument instead of literal text. Be aware that Autoconf 2.61 will not
+ work with this option enabled with the default regular expression; but
+ Autoconf 2.62 will be compatible with this option.
+
+** Improved portability to platforms such as BSD/OS and AIX.
+
+* Version 1.4.8 - 20 November 2006, by Eric Blake (CVS version 1.4.7a)
+
+** The `divert' macro and `-H'/`--hashsize' command line option no longer
+ cause a core dump when handed extra large values. Also, `divert' now
+ uses memory proportional to the number of diversions in use, rather than
+ to the maximum diversion number encountered, so that large diversion
+ numbers are less likely to exhaust system memory; and is no longer
+ limited by the maximum number of file descriptors.
+
+** The `--help' and `--version' command line options now consistently
+ override all earlier options. For example, `m4 --debugfile=trace
+ --help' now no longer accidentally creates an empty file `trace'.
+
+** The `-L'/`--nesting-limit' command line option can now be set to 0
+ to remove the default limit of 1024. However, it is still possible that
+ heavily nested input can cause abrupt program termination due to stack
+ overflow.
+
+** Problems encountered when writing to standard error, such as with the
+ `errprint' macro, now always cause a non-zero exit status.
+
+** Warnings and errors issued during macro expansion are now consistently
+ reported at the line where the macro name was detected, rather than
+ where the close parenthesis resides. Text wrapped by `m4wrap' now
+ remembers the location that was in effect when m4wrap was invoked,
+ rather than changing to line 0 and the empty string for a file. The
+ macros `__line__' and `__file__' now work correctly even as the last
+ token in an included file.
+
+** The `builtin' and `indir' macros now transparently handle builtin
+ tokens generated by `defn'.
+
+** When diversions created by the `divert' macro collect enough text that
+ M4 must use temporary files, the environment variable $TMPDIR is now
+ consulted, and a better effort is made to clean up those files in the
+ event of a fatal signal.
+
+** The `mkstemp' builtin is added with the same GNU semantics as `maketemp',
+ based on the recommendation of POSIX to deprecate the POSIX semantics of
+ `maketemp' as inherently insecure. In GNU mode (no -G supplied on the
+ command line), `maketemp' silently retains the secure GNU semantics, but
+ a future release of M4 will change this to emit a warning. In
+ traditional mode (m4 -G), `maketemp' now uses the POSIX-mandated
+ insecure semantics, and issues a warning that you should convert your
+ script to use `mkstemp' instead. Additionally, `mkstemp' and `maketemp'
+ are now well-defined even if the template argument does not end in six
+ `X' characters.
+
+** The manual has been improved, including a new section on a composite
+ macro `foreach'.
+
+** The `changecom' and `changequote' macros now treat an empty second
+ argument the same as if it were missing, rather than using the empty
+ string and making it impossible to end a comment or quote.
+
+** The `translit' macro now operates in linear instead of quadratic time,
+ and is now eight-bit clean.
+
+** The `-D', `-U', `-s', and `-t' command line options now take effect
+ after any files encountered earlier on the command line, rather than up
+ front, as is done in traditional implementations and required by POSIX.
+
+* Version 1.4.7 - 25 September 2006, by Eric Blake (CVS version 1.4.6a)
+
+** Fix regression from 1.4.5 in handling a file that ends in a macro
+ expansion without arguments instead of a newline.
+
+** The define and pushdef macros now warn when the first argument is not
+ a string, rather than silently doing nothing.
+
+** Standard input can now be read more than once, as in 'm4 - file -', and
+ is not closed until all wrapped text is handled. This makes a
+ difference when stdin is not a regular file, and also fixes bugs when
+ using the syscmd or esyscmd macros from wrapped text.
+
+** When standard input is a seekable file, the m4exit, syscmd, and esyscmd
+ macros now restore the current position to the next unread byte rather
+ than discarding an arbitrary amount of buffered data.
+
+** SysV command-line compatibility is no longer a goal of GNU M4; the
+ focus will be instead on POSIX compatibility. This release continues to
+ support previous usage, but adds warnings in areas which will allow a
+ future version of GNU M4 to use its own extensions without being tied to
+ the SysV command line interface.
+
+** The no-op compatibility command line options -B, -N, -S, -T, and
+ --diversions may be withdrawn or assigned new meanings in future
+ releases, so they now issue a warning if used.
+
+** A new command line option -i replaces the compatibility -e as the
+ short spelling of --interactive, for consistency with other GNU tools; a
+ warning is issued if the old spelling is used, and it may be assigned
+ new meaning in future releases.
+
+** A new command line option --debugfile replaces the options -o and
+ --error-output as the preferred spelling. The old options were
+ misleading in their names and inconsistent with other GNU tools; they
+ are still silently accepted, but no longer documented in --help, and may
+ be assigned new meanings in future releases.
+
+* Version 1.4.6 - 25 August 2006, by Eric Blake (CVS version 1.4.5a)
+
+** Fix buffer overruns in regexp and patsubst macros when handed a trailing
+ backslash in the replacement text, or when handling \n substitutions
+ beyond the number of \(\) groups.
+
+** Fix memory leak in regexp, patsubst, and changeword macros.
+
+** The format macro now understands %F, %g, and %G.
+
+** When loading frozen files, m4 now exits with status 63 if version
+ mismatch is detected.
+
+** Fix bugs that occurred when invoked with stdout or stderr closed,
+ and detect write failures to stdout or to the target of the debugfile
+ macro. In particular, the syscmd and esyscmd macros can no longer
+ interfere with the debug stream or diversions.
+
+** The m4exit macro now converts values outside the range 0-255 to 1.
+
+** It is now an error if a command-line input file ends in the middle of a
+ comment, matching the behavior of mid-string and mid-argument
+ collection.
+
+** The dnl macro now warns if end of file is encountered instead of a
+ newline.
+
+** The error message when end of file is encountered now uses the file and
+ line where the dangling construct started, rather than `NONE:0:'.
+
+** The debugmode and __file__ macros, and the -s/--synclines option, now
+ show what directory a file was found in when the -I/--include option or
+ M4PATH variable had an effect.
+
+** The changequote and changecom macros now work with 8-bit characters, and
+ quotes and comments that begin with `(' are properly recognized
+ following a word.
+
+** The new macro __program__ is added, which allows the input file to issue
+ an error message that resembles messages from m4. Warning and error
+ messages have been reformatted to comply with GNU Coding Standards.
+
+** The errprint, m4wrap, and shift macros are now recognized only with
+ arguments.
+
+** The index, substr, translit, regexp, and patsubst macros now produce
+ output when given only one argument, but still warn about a missing
+ second argument.
+
+** The patsubst macro now reliably finds zero-length matches at the end
+ of a string.
+
+* Version 1.4.5 - 15 July 2006, by Eric Blake (CVS version 1.4.4c)
+
+** Fix sysval on BeOS, OS/2, and other systems that store exit status
+ in the low-order byte. Additionally, on Unix platforms, if syscmd was
+ terminated by a signal, sysval now displays the signal number shifted
+ left by eight bits, to match traditional m4 implementations.
+
+** The maketemp macro is no longer subject to platform limitations (such as
+ 26 or 32 max files from a given template).
+
+** Frozen files now require that the first directive be V (version), to
+ better diagnose version mismatch. Additionally, if the F directive
+ (builtin function) names an unknown builtin that existed in the m4 that
+ froze the file but not in the current m4 (for example, changeword), the
+ warning is deferred until an attempt is made to actually use the
+ builtin. This allows downgrading from beta m4-1.4o to stable m4-1.4.5
+ without breaking autoconf.
+
+** The format and indir macros are now recognized only with arguments.
+
+** The eval macro no longer crashes on x86 architectures when dividing the
+ minimum integer by -1.
+
+** On systems with ecvt and fcvt, format no longer truncates trailing
+ zeroes on integers printed with %.0f. On systems without these
+ functions, format is no longer subject to a buffer overflow that
+ permitted arbitrary code execution.
+
+** On native Windows builds, the macro __windows__ is provided instead of
+ __unix__. Likewise, on OS/2 builds, the macro __os2__ is provided.
+ This allows input files to determine when syscmd might behave
+ differently.
+
+** Fix bug in 1.4.3 patch to use \n line-endings that did not work for
+ cygwin.
+
+** When given the empty string or 0, undivert is now documented as a no-op
+ rather than closing stdout, warning about a non-existent file, or trying
+ to read a directory as a file.
+
+** Many documentation improvements. Also, the manual is now distributed
+ under FDL 1.2, rather than a stricter verbatim-only license.
+
+** Raise the -L (--nesting-limit) command line option limit from 250 to
+ 1024.
+
+** The decr, incr, divert, m4exit, and substr macros treat an empty number
+ as 0, issue a warning, and expand as normal; rather than issuing an
+ error and expanding to the empty string.
+
+** The eval macro now treats an empty radix argument as 10, handles radix 1,
+ and treats the width argument as number of digits excluding the sign,
+ for compatibility with other m4 implementations.
+
+** The ifdef, divert, m4exit, substr, and translit macros now correctly
+ ignore extra arguments.
+
+** The popdef and undefine macros now correctly accept multiple arguments.
+
+** Although changeword is on its last leg, if enabled, it now reverts to the
+ default (faster) regexp when passed the empty string.
+
+** The regexp and substr macros now warn and ignore a trailing backslash in
+ the replacement, and warn on \n for n larger than the number of
+ sub-expressions in the regexp.
+
+* Version 1.4.4b - 17 June 2006, by Eric Blake (CVS version 1.4.4a)
+
+** Fix a recursive push_string crashing bug, which affected changequote of
+ three or more characters on some compilers.
+
+** Use automake to fix build portability issues.
+
+** Fix a recursive m4wrap crashing bug.
+
+** Fix a 1 in 2**32 hash crashing bug.
+
+** Tracing a macro by name is now persistent, even if the macro is
+ subsequently undefined or redefined. The traceon and traceoff macros no
+ longer warn about undefined symbols. This solves a crash when using
+ indir on an undefined macro traced with the -t option, as well as an
+ incorrect result of ifdef. Furthermore, tracing is no longer
+ transferred with builtins, solving the bug of "m4 -tm4_eval" failing to
+ give trace output on the input
+ "define(`m4_eval',defn(`eval'))m4_eval(1)".
+
+** Fix a crash when a macro is undefined while collecting its arguments, by
+ always using the definition that was in effect before argument
+ collection. This behavior matches the C pre-processor, and means that
+ the sequence "define(`f',`1')f(define(`f',`2'))f" is now documented to
+ result in "12", rather than the previously undocumented "22".
+
+** Update the regex engine to fix several bugs.
+
+** Fix a potential crash on machines where char is signed.
+
+* Version 1.4.4 - October 2005, by Gary V. Vaughan
+
+** ./configure --infodir=/usr/share/info now works correctly.
+
+** When any file named on the command line is missing exit with status 1.
+
+* Version 1.4.3 - March 2005, by Gary V. Vaughan
+
+** DESTDIR installs now work correctly.
+
+** Don't segfault with uncompilable regexps to changeword().
+
+** Always use \n line-endings for frozen files (fixes a Windows bug).
+
+** Portability fix for systems lacking mkstemp(3).
+
+** Approximately 20% speed up in the common case of usage with autoconf.
+
+** Supported on QNX 6.3.
+
+* Version 1.4.2 - August 2004, by Paul Eggert
+
+** No user visible changes; portability bug fixes only.
+
+* Version 1.4.1 - June 2004, by Paul Eggert
+
+** The 1.4.x series is intended to be stable; features added in 1.4[a-q]
+ were not backported to 1.4.x unless specifically mentioned above.
+
+** maketemp now creates an empty file with the given name, instead of merely
+ returning the name of a nonexistent file. This closes a security hole.
* Version beta 1.4q - August 2001, by Gary V. Vaughan
@@ -355,13 +670,6 @@
*** All 8-bit characters can now be used for quotes.
-FIXME: include the (long) list of changes in 1.4.x that were not already
- in earlier betas.
-* Version 1.4.4
-* Version 1.4.3
-* Version 1.4.2
-* Version 1.4.1
-
* Version 1.4 - October 1994, by Franc,ois Pinard
** (No user visible changes)
Index: src/freeze.c
===================================================================
RCS file: /sources/m4/m4/src/freeze.c,v
retrieving revision 1.61
diff -u -r1.61 freeze.c
--- src/freeze.c 25 Feb 2007 23:19:32 -0000 1.61
+++ src/freeze.c 28 Feb 2007 21:24:37 -0000
@@ -239,12 +239,12 @@
|| strcmp (m4_get_syntax_rquote (M4SYNTAX), DEF_RQUOTE))
{
fprintf (file, "Q%lu,%lu\n",
- (unsigned long int) context->syntax->lquote.length,
- (unsigned long int) context->syntax->rquote.length);
- produce_mem_dump (file, context->syntax->lquote.string,
- context->syntax->lquote.length);
- produce_mem_dump (file, context->syntax->rquote.string,
- context->syntax->rquote.length);
+ (unsigned long int) M4SYNTAX->lquote.length,
+ (unsigned long int) M4SYNTAX->rquote.length);
+ produce_mem_dump (file, M4SYNTAX->lquote.string,
+ M4SYNTAX->lquote.length);
+ produce_mem_dump (file, M4SYNTAX->rquote.string,
+ M4SYNTAX->rquote.length);
fputc ('\n', file);
}
@@ -254,12 +254,10 @@
|| strcmp (m4_get_syntax_ecomm (M4SYNTAX), DEF_ECOMM))
{
fprintf (file, "C%lu,%lu\n",
- (unsigned long int) context->syntax->bcomm.length,
- (unsigned long int) context->syntax->ecomm.length);
- produce_mem_dump (file, context->syntax->bcomm.string,
- context->syntax->bcomm.length);
- produce_mem_dump (file, context->syntax->ecomm.string,
- context->syntax->ecomm.length);
+ (unsigned long int) M4SYNTAX->bcomm.length,
+ (unsigned long int) M4SYNTAX->ecomm.length);
+ produce_mem_dump (file, M4SYNTAX->bcomm.string, M4SYNTAX->bcomm.length);
+ produce_mem_dump (file, M4SYNTAX->ecomm.string, M4SYNTAX->ecomm.length);
fputc ('\n', file);
}
@@ -495,7 +493,7 @@
m4__module_open (context, "gnu", NULL);
/* Disable { and } categories, since ${11} was not supported in
1.4.x. */
- m4_set_syntax (context->syntax, 'O', '+', "{}");
+ m4_set_syntax (M4SYNTAX, 'O', '+', "{}");
break;
default:
if (version > 2)
@@ -646,7 +644,7 @@
/* Syntax under M4_SYNTAX_MASKS is handled specially; all
other characters are additive. */
- if ((m4_set_syntax (context->syntax, syntax,
+ if ((m4_set_syntax (M4SYNTAX, syntax,
(m4_syntax_code (syntax) & M4_SYNTAX_MASKS
? '=' : '+'), string[0]) < 0)
&& (syntax != '\0'))
Index: doc/m4.texinfo
===================================================================
RCS file: /sources/m4/m4/doc/m4.texinfo,v
retrieving revision 1.97
diff -u -r1.97 m4.texinfo
--- doc/m4.texinfo 28 Feb 2007 14:36:22 -0000 1.97
+++ doc/m4.texinfo 28 Feb 2007 21:24:37 -0000
@@ -655,11 +655,12 @@
@item address@hidden@address@hidden
@itemx address@hidden@address@hidden
Set the regular expression syntax according to @var{RESYNTAX-SPEC}.
-When this option is not given, @var{RESYNTAX-SPEC} is omitted,
address@hidden M4 uses emacs compatible regular expressions.
address@hidden, for more details on the format and meaning of
address@hidden This option may be given more than once, and order
-with respect to file names is significant.
+When this option is not given, or @var{RESYNTAX-SPEC} is omitted,
address@hidden M4 uses the flavor @code{GNU_M4}, which provides
+emacs-compatible regular expressions. @xref{Changeresyntax}, for more
+details on the format and meaning of @var{RESYNTAX-SPEC}. This option
+may be given more than once, and order with respect to file names is
+significant.
@item --safer
Cripple the following builtins, since each can perform potentially
@@ -735,13 +736,12 @@
@item -D @address@hidden@address@hidden
@itemx address@hidden@address@hidden@r{]}
-This enters @var{NAME} into the symbol table, before any input files are
-read. If @address@hidden is missing, the value is taken to be the
-empty string. The @var{VALUE} can be any string, and the macro can be
-defined to take arguments, just as if it was defined from within the
-input. This option may be given more than once; order with respect to
-file names is significant, and redefining the same @var{NAME} loses the
-previous value.
+This enters @var{NAME} into the symbol table. If @address@hidden is
+missing, the value is taken to be the empty string. The @var{VALUE} can
+be any string, and the macro can be defined to take arguments, just as
+if it was defined from within the input. This option may be given more
+than once; order with respect to file names is significant, and
+redefining the same @var{NAME} loses the previous value.
@item --import-environment
Imports every variable in the environment as a macro. This is done
@@ -763,13 +763,12 @@
@item -p @address@hidden@address@hidden
@itemx address@hidden@address@hidden@r{]}
-This enters @var{NAME} into the symbol table, before any input files are
-read. If @address@hidden is missing, the value is taken to be the
-empty string. The @var{VALUE} can be any string, and the macro can be
-defined to take arguments, just as if it was defined from within the
-input. This option may be given more than once; order with respect to
-file names is significant, and redefining the same @var{NAME} adds
-another definition to its stack.
+This enters @var{NAME} into the symbol table. If @address@hidden is
+missing, the value is taken to be the empty string. The @var{VALUE} can
+be any string, and the macro can be defined to take arguments, just as
+if it was defined from within the input. This option may be given more
+than once; order with respect to file names is significant, and
+redefining the same @var{NAME} adds another definition to its stack.
@item -s
@itemx --synclines
@@ -1924,6 +1923,20 @@
@result{}1
@end example
+Remember that @samp{#} defaults to the comment character; if you forget
+quotes to inhibit the comment behavior, your macro definition may not
+end where you expected.
+
address@hidden
+dnl Attempt to define a macro to just `$#'
+define(underquoted, $#)
+oops)
address@hidden
+underquoted
address@hidden)
address@hidden
address@hidden example
+
The notation @code{$*} can be used in the expansion text to denote all
the actual arguments, unquoted, with commas in between. For example
@@ -4168,7 +4181,8 @@
the value of @var{resyntax}, equivalent to passing @var{resyntax} as the
argument to the command line option @option{--regexp-syntax}
(@pxref{Operation modes, , Invoking m4}). If @var{resyntax} is empty,
-the default flavor is reverted to emacs style.
+the default flavor is reverted to the @code{GNU_M4} style, compatible
+with emacs.
@var{resyntax} can be any one of the values in the table below. Case is
not important, and @kbd{-} or @kbd{ } can be substituted for @kbd{_} in
@@ -4354,8 +4368,6 @@
@comment FIXME - we should also consider supporting:
@comment @item Ignore - characters that are ignored if they appear in
@comment the input; perhaps defaulting to '\0', category 'I'.
address@hidden @item Assign -character used in macro definitions for default
address@hidden variables, category '='.
@end table
@noindent
@@ -4412,6 +4424,10 @@
Argument separator
@item $
Dollar
address@hidden @{
+Left brace
address@hidden @}
+Right brace
@item O
Other
@item @@
@@ -4428,8 +4444,6 @@
End comment
@comment @item I
@comment Ignore
address@hidden @item =
address@hidden Assign
@end table
The remaining characters of each @var{syntax-spec} form the set of
@@ -6046,11 +6060,10 @@
@end deffn
All binary operators, except exponentiation, are left associative. C
-operators that perform variable assignment, such as @samp{=} or
address@hidden, are forbidden by @acronym{POSIX}, since @code{eval} only
-operates on constants, not variables. Attempting to use them results
-in an error.
address@hidden fixme If XCU ERN 137 is approved, then we could provide an
+operators that perform variable assignment, such as @samp{+=} or
address@hidden, are not implemented, since @code{eval} only operates on
+constants, not variables. Attempting to use them results in an error.
address@hidden FIXME - since XCU ERN 137 is approved, we could provide an
@comment extension that supported assignment operators.
Note that some older @code{m4} implementations use @samp{^} as an
@@ -6122,6 +6135,7 @@
which shifts in 0 bits rather than twos-complement sign-extension. A
ratio operator @samp{\} behaves like normal division @samp{/} on
integers, but is provided for symmetry with @code{mpeval}.
+Additionally, the C operators @samp{,} and @samp{?:} are supported.
@example
eval(`2 ** 3 ** 2')
@@ -6146,40 +6160,18 @@
@result{}1
eval(`6 \ 3')
@result{}2
address@hidden example
-
-Furthermore, when you do not use the @option{--traditional} command line
-option (or @option{-G}, @pxref{Limits control, , Invoking m4}), the C
-operators @samp{,} and @samp{?:} are supported. But in traditional
-mode, @acronym{POSIX} requires that the use of these two operators cause
-an error.
-
address@hidden
-$ @kbd{m4}
-eval(`1?2:3')
+eval(`1 ? 2 : 3')
@result{}2
-eval(`0?2:3')
+eval(`0 ? 2 : 3')
@result{}3
-eval(`1?2:1/0')
+eval(`1 ? 2 : 1/0')
@result{}2
-eval(`0?1/0:3')
+eval(`0 ? 1/0 : 3')
@result{}3
-eval(`4,5')
+eval(`4, 5')
@result{}5
@end example
address@hidden options: -G
address@hidden status: 1
address@hidden
-$ @kbd{m4 --posix}
-eval(`1?2:3')
address@hidden:stdin:1: eval: invalid operator: 1?2:3
address@hidden
-eval(`4,5')
address@hidden:stdin:2: eval: invalid operator: 4,5
address@hidden
address@hidden example
-
Within @var{expression}, (but not @var{radix} or @var{width}), numbers
without a special prefix are decimal. A simple @samp{0} prefix
introduces an octal number. @samp{0x} introduces a hexadecimal number.
Index: m4/symtab.c
===================================================================
RCS file: /sources/m4/m4/m4/symtab.c,v
retrieving revision 1.70
diff -u -r1.70 symtab.c
--- m4/symtab.c 27 Jan 2007 00:25:14 -0000 1.70
+++ m4/symtab.c 28 Feb 2007 21:24:37 -0000
@@ -32,15 +32,16 @@
simply ordered on the stack by age. The most recently pushed definition
will then always be the first found.
- Also worthy of mention is the way traced symbols are managed: the trace
- bit is associated with a particular symbol name. If a symbol is
- undefined and then redefined, it does not lose its trace bit (in GNU
- mode). This is achieved by not removing traced symbol names from the
- symbol table, even if their value stack is empty. That way, when the
- name is given a new value, it is pushed onto the empty stack, and the
- trace bit attached to the name was never lost. There is a small amount
- of fluff in these functions to make sure that such symbols (with empty
- value stacks) are invisible to the users of this module. */
+ Also worthy of mention is the way traced symbols are managed: the
+ trace bit is associated with a particular symbol name. If a symbol
+ is undefined and then redefined, it does not lose its trace bit.
+ This is achieved by not removing traced symbol names from the
+ symbol table, even if their value stack is empty. That way, when
+ the name is given a new value, it is pushed onto the empty stack,
+ and the trace bit attached to the name was never lost. There is a
+ small amount of fluff in these functions to make sure that such
+ symbols (with empty value stacks) are invisible to the users of
+ this module. */
#define M4_SYMTAB_DEFAULT_SIZE 2047
Index: modules/evalparse.c
===================================================================
RCS file: /sources/m4/m4/modules/evalparse.c,v
retrieving revision 1.16
diff -u -r1.16 evalparse.c
--- modules/evalparse.c 6 Jan 2007 19:56:54 -0000 1.16
+++ modules/evalparse.c 28 Feb 2007 21:24:37 -0000
@@ -341,9 +341,6 @@
numb_init (v2);
while ((et = eval_lex (&v2)) == COMMA)
{
- /* Unless XCU ERN 137 is approved, eval must reject this in
- POSIX mode. */
- numb_extension (context);
et = eval_lex (&v2);
if (et == ERROR)
return UNKNOWN_INPUT;
@@ -374,9 +371,6 @@
numb_init (v3);
if ((et = eval_lex (&v2)) == QUESTION)
{
- /* Unless XCU ERN 137 is approved, eval must reject this in
- POSIX mode. */
- numb_extension (context);
et = eval_lex (&v2);
if (et == ERROR)
return UNKNOWN_INPUT;
Index: modules/m4.c
===================================================================
RCS file: /sources/m4/m4/modules/m4.c,v
retrieving revision 1.103
diff -u -r1.103 m4.c
--- modules/m4.c 28 Feb 2007 14:36:22 -0000 1.103
+++ modules/m4.c 28 Feb 2007 21:24:37 -0000
@@ -1111,15 +1111,6 @@
#define numb_urshift(c, x, y) \
(*(x) = (number) ((unumber) *(x) >> (unumber) *(y)))
-#define numb_extension(c) \
- do \
- { \
- /* Revisit this if XCU ERN 137 is approved. */ \
- if (m4_get_posixly_correct_opt (context)) \
- return INVALID_OPERATOR; \
- } \
- while (0)
-
/* The function ntoa () converts VALUE to a signed ascii representation in
radix RADIX. */
Index: modules/mpeval.c
===================================================================
RCS file: /sources/m4/m4/modules/mpeval.c,v
retrieving revision 1.23
diff -u -r1.23 mpeval.c
--- modules/mpeval.c 15 Jan 2007 14:04:27 -0000 1.23
+++ modules/mpeval.c 28 Feb 2007 21:24:37 -0000
@@ -143,7 +143,6 @@
static void numb_lshift (m4 *context, number *x, number *y);
static void numb_rshift (m4 *context, number *x, number *y);
#define numb_urshift(c, x, y) numb_rshift (c, x, y)
-#define numb_extension(c) /* no-op */
static number numb_ZERO;
Index: src/main.c
===================================================================
RCS file: /sources/m4/m4/src/main.c,v
retrieving revision 1.108
diff -u -b -r1.108 main.c
--- src/main.c 5 Feb 2007 17:31:10 -0000 1.108
+++ src/main.c 28 Feb 2007 21:24:47 -0000
@@ -33,12 +33,12 @@
#define AUTHORS _("Rene' Seindal"), "Gary V. Vaughan", "Eric Blake"
-typedef struct macro_definition
+typedef struct deferred
{
- struct macro_definition *next;
+ struct deferred *next;
int code; /* deferred optchar */
- const char *macro;
-} macro_definition;
+ const char *value;
+} deferred;
/* Error handling functions. */
@@ -92,7 +92,7 @@
-i, --interactive unbuffer output, ignore interrupts\n\
-P, --prefix-builtins force a `m4_' prefix to all builtins\n\
-Q, --quiet, --silent suppress some warnings for builtins\n\
- -r, --regexp-syntax[=SPEC] set default regexp syntax to SPEC [EMACS]\n\
+ -r, --regexp-syntax[=SPEC] set default regexp syntax to SPEC [GNU_M4]\n\
--safer disable potentially unsafe builtins\n\
-W, --warnings enable all warnings\n\
"), stdout);
@@ -325,13 +325,12 @@
int
main (int argc, char *const *argv, char *const *envp)
{
- macro_definition *head = NULL; /* head of deferred argument list */
- macro_definition *tail = NULL;
- macro_definition *defn;
+ deferred *head = NULL; /* head of deferred argument list */
+ deferred *tail = NULL;
+ deferred *defn;
int optchar; /* option character */
size_t size; /* for parsing numeric option arguments */
- macro_definition *defines;
bool read_stdin = false; /* true iff we have read from stdin */
bool import_environment = false; /* true to import environment */
bool seen_file = false;
@@ -428,7 +427,7 @@
defn = xmalloc (sizeof *defn);
defn->code = optchar;
- defn->macro = optarg;
+ defn->value = optarg;
defn->next = NULL;
if (head == NULL)
@@ -641,7 +640,7 @@
{
defn = xmalloc (sizeof *defn);
defn->code = 'D';
- defn->macro = *env;
+ defn->value = *env;
defn->next = head;
head = defn;
}
@@ -649,22 +648,20 @@
/* Handle deferred command line macro definitions. Must come after
initialization of the symbol table. */
+ defn = head;
+ while (defn != NULL)
{
- defines = head;
+ deferred *next;
+ const char *arg = defn->value;
- while (defines != NULL)
- {
- macro_definition *next;
- const char *arg = defines->macro;
-
- switch (defines->code)
+ switch (defn->code)
{
case 'D':
case 'p':
{
m4_symbol_value *value = m4_symbol_value_create ();
- /* defines->arg is read-only, so we need a copy. */
+ /* defn->value is read-only, so we need a copy. */
char *macro_name = xstrdup (arg);
char *macro_value = strchr (macro_name, '=');
@@ -673,7 +670,7 @@
m4_set_symbol_value_text (value, xstrdup (macro_value
? macro_value : ""));
- if (defines->code == 'D')
+ if (defn->code == 'D')
m4_symbol_define (M4SYMTAB, macro_name, value);
else
m4_symbol_pushdef (M4SYMTAB, macro_name, value);
@@ -691,13 +688,10 @@
break;
case 'r':
- m4_set_regexp_syntax_opt (context,
- m4_regexp_syntax_encode (arg));
+ m4_set_regexp_syntax_opt (context, m4_regexp_syntax_encode (arg));
if (m4_get_regexp_syntax_opt (context) < 0)
- {
m4_error (context, EXIT_FAILURE, 0,
_("bad regexp syntax option: `%s'"), arg);
- }
break;
case 't':
@@ -737,10 +731,9 @@
abort ();
}
- next = defines->next;
- free (defines);
- defines = next;
- }
+ next = defn->next;
+ free (defn);
+ defn = next;
}
/* Handle remaining input files. Each file is pushed on the input,