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I'm backporting the feature on the master branch of allowing a second
parameter to divert to branch-1.6, as follows.
- --
Don't work too hard, make some time for fun as well!
Eric Blake [EMAIL PROTECTED]
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>From 9f5e389c810aacbd70b04f2530aa52a897cd0ad9 Mon Sep 17 00:00:00 2001
From: Eric Blake <[EMAIL PROTECTED]>
Date: Fri, 28 Nov 2008 07:46:57 -0700
Subject: [PATCH] Add extension to divert builtin.
* src/builtin.c (m4_divert): Support optional second parameter.
* src/output.c (divert_text): Optimize empty output.
* doc/m4.texinfo (Divert): Document the extension.
* NEWS: Likewise.
* THANKS: Update.
Reported by Daniel Richard G.
Signed-off-by: Eric Blake <[EMAIL PROTECTED]>
(cherry picked from commit 4f82b1e37666722c57e9e6fd2495d9c1cd694db8)
---
ChangeLog | 10 +++++++++
NEWS | 5 ++++
THANKS | 1 +
doc/m4.texinfo | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
src/builtin.c | 3 +-
src/output.c | 2 +-
6 files changed, 79 insertions(+), 3 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index d100a59..2085dea 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2008-11-28 Eric Blake <[EMAIL PROTECTED]>
+
+ Add extension to divert builtin.
+ * src/builtin.c (m4_divert): Support optional second parameter.
+ * src/output.c (divert_text): Optimize empty output.
+ * doc/m4.texinfo (Divert): Document the extension.
+ * NEWS: Likewise.
+ * THANKS: Update.
+ Reported by Daniel Richard G.
+
2008-11-26 Eric Blake <[EMAIL PROTECTED]>
Keep COPYING in repository.
diff --git a/NEWS b/NEWS
index bb61b72..3fb4d90 100644
--- a/NEWS
+++ b/NEWS
@@ -42,6 +42,11 @@ Foundation, Inc.
then apply this patch:
http://git.sv.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=56d42fa71
+** The `divert' builtin now accepts an optional second argument of text
+ that is immediately placed in the new diversion, regardless of whether
+ the current expansion is nested within argument collection of another
+ macro.
+
** The `-d'/`--debug' command-line option now understands `-' and `+'
modifiers, the way the builtin `debugmode' has always done; this allows
`-d-V' to disable prior debug settings from the command line, similar to
diff --git a/THANKS b/THANKS
index 6a048b9..bb8a651 100644
--- a/THANKS
+++ b/THANKS
@@ -28,6 +28,7 @@ Cesar Strauss [EMAIL PROTECTED]
Chris McGuire [EMAIL PROTECTED]
Damian Menscher [EMAIL PROTECTED]
Dan Jacobson [EMAIL PROTECTED]
+Daniel Richard G. [EMAIL PROTECTED]
David J. MacKenzie [EMAIL PROTECTED]
David Perlin [EMAIL PROTECTED]
Elbert Pol [EMAIL PROTECTED]
diff --git a/doc/m4.texinfo b/doc/m4.texinfo
index f77a6b5..8301bb7 100644
--- a/doc/m4.texinfo
+++ b/doc/m4.texinfo
@@ -5603,11 +5603,17 @@ Divert
@cindex files, diverting output to
Output is diverted using @code{divert}:
[EMAIL PROTECTED] Builtin divert (@dvar{number, 0})
[EMAIL PROTECTED] Builtin 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
@@ -5671,6 +5677,59 @@ Divert
@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', `$1')
[EMAIL PROTECTED]
+echo(divert(`1')`one'divert(`2'))`'dnl
+echo(`divert(`3')three`'divert(`4')')`'dnl
+echo(divert(`5', `five')divert(`6'))`'dnl
+divert
[EMAIL PROTECTED]
+undivert(`1')
[EMAIL PROTECTED]
+undivert(`2')
[EMAIL PROTECTED]
+undivert(`3')
[EMAIL PROTECTED]
+undivert(`4')
[EMAIL PROTECTED]
+undivert(`5')
[EMAIL PROTECTED]
+undivert(`6')
[EMAIL PROTECTED]
[EMAIL PROTECTED] example
+
[EMAIL PROTECTED]
[EMAIL PROTECTED] additional tests, not worth documenting in manual
+
[EMAIL PROTECTED] options: -s
[EMAIL PROTECTED]
+$ @kbd{m4 -s}
+define(`echo', `$1')dnl
+divert(`-1', `discarded without warning')
+divert`'dnl
+echo(` world'divert(divnum, `hello'))
[EMAIL PROTECTED] 4 "stdin"
[EMAIL PROTECTED] world
[EMAIL PROTECTED] example
[EMAIL PROTECTED] ignore
+
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
diff --git a/src/builtin.c b/src/builtin.c
index 267292c..24f2df6 100644
--- a/src/builtin.c
+++ b/src/builtin.c
@@ -1304,11 +1304,12 @@ m4_divert (struct obstack *obs, int argc,
macro_arguments *argv)
const call_info *me = arg_info (argv);
int i = 0;
- bad_argc (me, argc, 0, 1);
+ bad_argc (me, argc, 0, 2);
if (argc >= 2 && !numeric_arg (me, ARG (1), &i))
return;
make_diversion (i);
+ divert_text (NULL, ARG (2), ARG_LEN (2), current_line);
}
/*-----------------------------------------------------.
diff --git a/src/output.c b/src/output.c
index 6d74ecd..6a02b80 100644
--- a/src/output.c
+++ b/src/output.c
@@ -479,7 +479,7 @@ divert_text (struct obstack *obs, const char *text, int
length, int line)
/* Do nothing if TEXT should be discarded. */
- if (output_diversion == NULL)
+ if (output_diversion == NULL || !length)
return;
/* Output TEXT to a file, or in-memory diversion buffer. */
--
1.6.0.4
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