-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
According to Daniel Richard G. on 5/21/2007 1:43 AM:
> In fact, it's a fairly simple patch. See attached for my stab at it. (Also,
> there's a more straightforward test input file.) I did the two-arg
> divert(), since that seems more natural than coming up with a new/separate
> builtin for this.
>
> I think this fills a hole in the core m4 feature set---right now, as I
> understand it, the only way to send text to a diversion is at the point
> when the text is actually being written out. With this, you can send text
> to a diversion in the same way that errprint() sends text to stderr:
> immediately upon evaluation of the builtin. Without regard to the invoking
> context.
Thanks again for the idea. And in the process of checking this in, I
discovered a regression from a couple days ago in handling hand-crafted
frozen files. Here's what I'm checking in to head. I'm porting the
regression fix, but not the new feature, to the branch.
2007-05-31 Eric Blake <[EMAIL PROTECTED]>
Add extension to divert builtin.
* modules/m4.c (builtin_divert): Immediately divert second
argument.
* m4/output.c (m4_output_text): Allow 0 length. Fixes regression
from two days ago.
(m4_shipout_text): Short-circuit on zero length.
* tests/freeze.at (loading format 2): Expand test to catch
regression. Also check out-of-range version.
* tests/builtins.at (divert): Expand test to check corner cases
of extension.
* NEWS: Document the extension.
Reported by Daniel Richard G.
- --
Don't work too hard, make some time for fun as well!
Eric Blake [EMAIL PROTECTED]
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.5 (Cygwin)
Comment: Public key at home.comcast.net/~ericblake/eblake.gpg
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
iD8DBQFGXszC84KuGfSFAYARApeAAKDV+0R/8Xxr9rRqn454PGWSASqvrQCfdMJm
yJJrW4hk+IlM9MxWjN8PlwY=
=aDjR
-----END PGP SIGNATURE-----
Index: NEWS
===================================================================
RCS file: /sources/m4/m4/NEWS,v
retrieving revision 1.42
diff -u -p -r1.42 NEWS
--- NEWS 24 Mar 2007 21:29:41 -0000 1.42
+++ NEWS 31 May 2007 13:21:59 -0000
@@ -157,6 +157,11 @@ promoted to 2.0.
information to the first line to show the definition of the macro being
expanded. The 'e' flag has been updated to output non-text expansions.
+*** The `divert' builtin now accepts an optional second argument of text
+ that is immediately placed on the new diversion, regardless of whether
+ the current expansion is nested within argument collection of another
+ macro.
+
*** The `dumpdef' builtin now always outputs to standard error, rather than
the debug file specified by the `--debugfile' option or `debugfile'
macro.
Index: doc/m4.texinfo
===================================================================
RCS file: /sources/m4/m4/doc/m4.texinfo,v
retrieving revision 1.105
diff -u -p -r1.105 m4.texinfo
--- doc/m4.texinfo 30 May 2007 13:36:58 -0000 1.105
+++ doc/m4.texinfo 31 May 2007 13:21:59 -0000
@@ -5008,11 +5008,17 @@ input file.
@cindex files, diverting output to
Output is diverted using @code{divert}:
[EMAIL PROTECTED] {Builtin (m4)} divert (@dvar{number, 0})
[EMAIL PROTECTED] {Builtin (m4)} divert (@dvar{number, 0}, @ovar{text})
The current diversion is changed to @var{number}. If @var{number} is left
out or empty, it is assumed to be zero. If @var{number} cannot be
parsed, the diversion is unchanged.
[EMAIL PROTECTED] @acronym{GNU} extensions
+As a @acronym{GNU} extension, if optional @var{text} is supplied and
[EMAIL PROTECTED] was valid, then @var{text} is immediately output to the
+new diversion, regardless of whether the expansion of @code{divert}
+occurred while collecting arguments for another macro.
+
The expansion of @code{divert} is void.
@end deffn
@@ -5076,6 +5082,44 @@ divert(`2')hello
@result{}world
@end example
+The ability to immediately output extra text is a @acronym{GNU}
+extension, but it can prove useful for ensuring that text goes to a
+particular diversion no matter how many pending macro expansions are in
+progress. For a demonstration of why this is useful, it is important to
+understand in the example below why @samp{one} is output in diversion 2,
+not diversion 1, while @samp{three} and @samp{five} both end up in the
+correctly numbered diversion. The key point is that when @code{divert}
+is executed unquoted as part of the argument collection of another
+macro, the side effect takes place immediately, but the text @samp{one}
+is not passed to any diversion until after the @samp{divert(`2')} and
+the enclosing @code{echo} have also taken place. The example with
[EMAIL PROTECTED] shows how following the quoting rule of thumb delays the
+invocation of @code{divert} until it is not nested in any argument
+collection context, while the example with @samp{five} shows the use of
+the optional argument to speed up the output process.
+
[EMAIL PROTECTED]
+define(`echo', `$1')
[EMAIL PROTECTED]
+echo(divert(`1')`one'divert(`2'))`'dnl
+echo(`divert(`3')three`'divert(`4')')`'dnl
+echo(divert(`5', `five')divert(`6'))`'dnl
+divert
[EMAIL PROTECTED]
+undivert(`1')
[EMAIL PROTECTED]
+undivert(`2')
[EMAIL PROTECTED]
+undivert(`3')
[EMAIL PROTECTED]
+undivert(`4')
[EMAIL PROTECTED]
+undivert(`5')
[EMAIL PROTECTED]
+undivert(`6')
[EMAIL PROTECTED]
[EMAIL PROTECTED] example
+
Note that @code{divert} is an English word, but also an active macro
without arguments. When processing plain text, the word might appear in
normal text and be unintentionally swallowed as a macro invocation. One
Index: m4/output.c
===================================================================
RCS file: /sources/m4/m4/m4/output.c,v
retrieving revision 1.44
diff -u -p -r1.44 output.c
--- m4/output.c 28 May 2007 21:48:41 -0000 1.44
+++ m4/output.c 31 May 2007 13:21:59 -0000
@@ -423,6 +423,9 @@ m4_output_text (m4 *context, const char
{
size_t count;
+ if (!output_diversion || !length)
+ return;
+
if (!output_file && length > output_unused)
make_room_for (context, length);
@@ -470,7 +473,7 @@ m4_shipout_text (m4 *context, m4_obstack
/* Do nothing if TEXT should be discarded. */
- if (output_diversion == NULL)
+ if (!output_diversion || !length)
return;
/* Output TEXT to a file, or in-memory diversion buffer. */
Index: modules/m4.c
===================================================================
RCS file: /sources/m4/m4/modules/m4.c,v
retrieving revision 1.109
diff -u -p -r1.109 m4.c
--- modules/m4.c 24 May 2007 20:13:44 -0000 1.109
+++ modules/m4.c 31 May 2007 13:21:59 -0000
@@ -70,7 +70,7 @@ extern void m4_make_temp (m4 *contex
BUILTIN (decr, false, true, true, 1, 1 ) \
BUILTIN (define, true, true, false, 1, 2 ) \
BUILTIN (defn, false, true, false, 1, -1 ) \
- BUILTIN (divert, false, false, false, 0, 1 ) \
+ BUILTIN (divert, false, false, false, 0, 2 ) \
BUILTIN (divnum, false, false, false, 0, 0 ) \
BUILTIN (dnl, false, false, false, 0, 0 ) \
BUILTIN (dumpdef, false, false, false, 0, -1 ) \
@@ -578,11 +578,16 @@ M4BUILTIN_HANDLER (decr)
M4BUILTIN_HANDLER (divert)
{
int i = 0;
+ const char *text;
if (argc >= 2 && !m4_numeric_arg (context, argc, argv, 1, &i))
return;
m4_make_diversion (context, i);
+
+ text = M4ARG (2);
+ m4_shipout_text (context, NULL, text, strlen (text),
+ m4_get_current_line (context));
}
/* Expand to the current diversion number. */
Index: tests/builtins.at
===================================================================
RCS file: /sources/m4/m4/tests/builtins.at,v
retrieving revision 1.40
diff -u -p -r1.40 builtins.at
--- tests/builtins.at 12 Apr 2007 17:41:35 -0000 1.40
+++ tests/builtins.at 31 May 2007 13:21:59 -0000
@@ -177,6 +177,17 @@ AT_CHECK_M4([divert.m4], 0,
Text diverted a second time.
]])
+dnl Test second divert argument, added for m4 2.0
+AT_DATA([in.m4], [[define(`echo',`$1')dnl
+divert(`-1', `discarded without warning')
+divert`'dnl
+echo(` world'divert(divnum, `hello'))
+]])
+
+AT_CHECK_M4([-s in.m4], [0], [[#line 4 "in.m4"
+hello world
+]])
+
AT_CLEANUP
Index: tests/freeze.at
===================================================================
RCS file: /sources/m4/m4/tests/freeze.at,v
retrieving revision 1.11
diff -u -p -r1.11 freeze.at
--- tests/freeze.at 28 May 2007 20:10:02 -0000 1.11
+++ tests/freeze.at 31 May 2007 13:21:59 -0000
@@ -163,6 +163,12 @@ M3
gnu
F7,7,3
builtinbuiltingnu
+# Text to negative diversion must not crash. Catches a regression
+# introduced 2007-05-28 and fixed 2007-05-31.
+D-1,5
+12345
+D0,0
+
# Testing escape sequences
T4,5
blah\t\477\040\X5C
@@ -188,6 +194,13 @@ bar
'7 \
]])
+dnl We don't support anything larger than format 2; make sure of that...
+AT_DATA([bogus.m4f], [[V3
+]])
+AT_CHECK_M4([-R bogus.m4f], [63], [],
+[[m4: frozen file version 3 greater than max supported of 2
+]])
+
AT_CLEANUP
_______________________________________________
M4-discuss mailing list
M4-discuss@gnu.org
http://lists.gnu.org/mailman/listinfo/m4-discuss
