[SCM] GNU M4 source repository branch, master, updated. 91b8f5afc665a8ba0cc2b0f06f371d4ae475809a

[Eric Blake]

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- Log -----------------------------------------------------------------
commit 91b8f5afc665a8ba0cc2b0f06f371d4ae475809a
Author: Eric Blake <address@hidden>
Date:   Sun Oct 28 21:26:41 2007 -0600

    More test coverage for autoconf usage patterns.
    
    * doc/m4.texinfo (Shift): Document cond macro, and add new test.
    * tests/macros.at (Rescanning macros): New test.
    * tests/builtins.at (include): Augment test.
    
    Signed-off-by: Eric Blake <address@hidden>

commit d9274c9c964e7c610833e77eca4fb9fd37b00200
Author: Ralf Wildenhues <address@hidden>
Date:   Sun Oct 28 18:27:38 2007 -0600

    ChangeLog for previous commit.

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog         |   11 ++++++++
 doc/m4.texinfo    |   71 +++++++++++++++++++++++++++++++++++++++++++++++-----
 tests/builtins.at |    9 ++++++
 tests/macros.at   |   29 +++++++++++++++++++++
 4 files changed, 113 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6f56dee..a78c048 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2007-10-28  Eric Blake  <address@hidden>
+
+       More test coverage for autoconf usage patterns.
+       * doc/m4.texinfo (Shift): Document cond macro, and add new test.
+       * tests/macros.at (Rescanning macros): New test.
+       * tests/builtins.at (include): Augment test.
+
+2007-10-28  Ralf Wildenhues  <address@hidden>
+
+       * Makefile.am: Adjust getopt handling to latest gnulib layout.
+
 2007-10-27  Eric Blake  <address@hidden>
 
        Document one use of changequote(`(',`)').
diff --git a/doc/m4.texinfo b/doc/m4.texinfo
index f84f4d3..54884a3 100644
--- a/doc/m4.texinfo
+++ b/doc/m4.texinfo
@@ -1508,16 +1508,16 @@ empty string.
 
 @cindex rescanning
 The output of macro evaluations is always rescanned.  The following
-example would yield the string @samp{de}, exactly as if @code{m4}
-has been given @address@hidden(`abcde', `3', `2')}} as input:
+example would yield the string @samp{bcd}, exactly as if @code{m4}
+has been given @address@hidden(`abcde', `1', `3')}} as input:
 
 @example
 define(`x', `substr(ab')
 @result{}
-define(`y', `cde, `3', `2')')
+define(`y', `cde, `1', `3')')
 @result{}
 x`'y
address@hidden
address@hidden
 @end example
 
 Unquoted strings on either side of a quoted string are subject to
@@ -2800,7 +2800,7 @@ as a multibranch, depending on the number of arguments 
supplied:
 @deffnx {Builtin (m4)} ifelse (@var{string-1}, @var{string-2}, @var{equal}, @
   @ovar{not-equal})
 @deffnx {Builtin (m4)} ifelse (@var{string-1}, @var{string-2}, @var{equal-1}, @
-  @var{string-3}, @var{string-4}, @var{equal-2}, @dots{})
+  @var{string-3}, @var{string-4}, @var{equal-2}, @dots{}, @ovar{not-equal})
 Used with only one argument, the @code{ifelse} simply discards it and
 produces no output.
 
@@ -2944,8 +2944,65 @@ reverse(`foo', `bar', `gnats', `and gnus')
 
 While not a very interesting macro, it does show how simple loops can be
 made with @code{shift}, @code{ifelse} and recursion.  It also shows
-that @code{shift} is usually used with @samp{$@@}.  Sometimes, a
-recursive algorithm requires adding quotes to each element:
+that @code{shift} is usually used with @samp{$@@}.  Another example of
+this is an implementation of a short-circuiting conditional operator.
+
address@hidden short-circuiting conditional
address@hidden conditional, short-circuiting
address@hidden Composite cond (@var{test-1}, @var{string-1}, @var{equal-1}, @
+  @ovar{test-2}, @ovar{string-2}, @ovar{equal-2}, @dots{}, @ovar{not-equal})
+Similar to @code{ifelse}, where an equal comparison between the first
+two strings results in the third, otherwise the first three arguments
+are discarded and the process repeats.  The difference is that each
address@hidden<n>} is expanded only when it is encountered.  This means that
+every third argument to @code{cond} is normally given one more level of
+quoting than the corresponding argument to @code{ifelse}.
address@hidden deffn
+
+Here is the implementation of @code{cond}, along with a demonstration of
+how it can short-circuit the side effects in @code{side}.  Notice how
+all the unquoted side effects happen regardless of how many comparisons
+are made with @code{ifelse}, compared with only the relevant effects
+with @code{cond}.
+
address@hidden
+define(`cond',
+`ifelse(`$#', `1', `$1',
+        `ifelse($1, `$2', `$3',
+                `$0(shift(shift(shift($@@))))')')')dnl
+define(`side', `define(`counter', incr(counter))$1')dnl
+define(`example1',
+`define(`counter', `0')dnl
+ifelse(side(`$1'), `yes', `one comparison: ',
+       side(`$1'), `no', `two comparisons: ',
+       side(`$1'), `maybe', `three comparisons: ',
+       `side(`default answer: ')')counter')dnl
+define(`example2',
+`define(`counter', `0')dnl
+cond(`side(`$1')', `yes', `one comparison: ',
+     `side(`$1')', `no', `two comparisons: ',
+     `side(`$1')', `maybe', `three comparisons: ',
+     `side(`default answer: ')')counter')dnl
+example1(`yes')
address@hidden comparison: 3
+example1(`no')
address@hidden comparisons: 3
+example1(`maybe')
address@hidden comparisons: 3
+example1(`feeling rather indecisive today')
address@hidden answer: 4
+example2(`yes')
address@hidden comparison: 1
+example2(`no')
address@hidden comparisons: 2
+example2(`maybe')
address@hidden comparisons: 3
+example2(`feeling rather indecisive today')
address@hidden answer: 4
address@hidden example
+
+Sometimes, a recursive algorithm requires adding quotes to each element,
+or treating multiple arguments as a single element:
 
 @deffn Composite quote (@dots{})
 @deffnx Composite dquote (@dots{})
diff --git a/tests/builtins.at b/tests/builtins.at
index 35b8a6b..a23aaa9 100644
--- a/tests/builtins.at
+++ b/tests/builtins.at
@@ -424,6 +424,15 @@ m4:include.m4:6: include: cannot open `NOFILE': No such 
file or directory
 
 AT_CHECK_M4([include.m4], 1, expout, experr)
 
+dnl make sure files are handled correctly even via builtin
+AT_DATA([foo], [[bar
+]])
+AT_DATA([in], [[builtin(`include', `foo')dnl
+]])
+
+AT_CHECK_M4([in], [0], [[bar
+]])
+
 AT_CLEANUP
 
 
diff --git a/tests/macros.at b/tests/macros.at
index fd9b176..3596baf 100644
--- a/tests/macros.at
+++ b/tests/macros.at
@@ -515,3 +515,32 @@ AT_CHECK_M4([in], [0], [[
 ]], [ignore])
 
 AT_CLEANUP
+
+
+## ----------------- ##
+## Rescanning macros ##
+## ----------------- ##
+
+AT_SETUP([Rescanning macros])
+
+dnl This is a series of tests that used to be included as undocumented tests
+dnl in the branch m4.texinfo.  They exercise rescanning issues not stressed
+dnl anywhere else in the suite, but which are used by autoconf.
+AT_DATA([in], [[define(`x1', `len(`$1'')dnl
+define(`y1', ``$1')')dnl
+x1(`01234567890123456789')y1(`98765432109876543210')
+]])
+
+AT_CHECK_M4([in], [0], [[40
+]])
+
+AT_DATA([in], [[define(`echo', `$@')dnl
+len((echo(`01234567890123456789',
+          `01234567890123456789')echo(`98765432109876543210',
+                                      `98765432109876543210')))
+]])
+
+AT_CHECK_M4([in], [0], [[84
+]])
+
+AT_CLEANUP


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