Add m4_set_map.

* lib/m4sugar/m4sugar.m4 (m4_set_foreach): New macro.
* tests/m4sugar.at (m4@&t@_set): Enhance test.
* doc/autoconf.texi (Set manipulation Macros) <m4_set_map>:
Document it.
* NEWS: Likewise.

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

diff --git a/ChangeLog b/ChangeLog
index 988018fea98252166090d37b08c1de8da3e21679..45a0434329dc9b1ffd159e725cd6d70619d8b62c 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2008-10-17  Eric Blake  <ebb9@byu.net>
 
+       Add m4_set_map.
+       * lib/m4sugar/m4sugar.m4 (m4_set_foreach): New macro.
+       * tests/m4sugar.at (m4@&t@_set): Enhance test.
+       * doc/autoconf.texi (Set manipulation Macros) <m4_set_map>:
+       Document it.
+       * NEWS: Likewise.
+
        Document m4_map_args.
        * lib/m4sugar/m4sugar.m4 (m4_transform, m4_transform_pair):
        Rename...

diff --git a/NEWS b/NEWS
index 664425cd16c44e2e64e4cf5a9f2e332901583c7a..1ba23cc5ffc56fdce282571b2a3f4f7965dc292b 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -13,7 +13,7 @@ GNU Autoconf NEWS - User visible changes.
 ** Configure scripts now use shell functions.
 
 ** The following m4sugar macros are new:
-   m4_default_quoted  m4_map_args  m4_map_args_pair
+   m4_default_quoted  m4_map_args  m4_map_args_pair  m4_set_map
 
 ** The following documented m4sh macros are new:
    AS_LINENO_PREPARE  AS_ME_PREPARE  AS_VAR_COPY

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 9573034ea2f68ca0754c6401e37a648185add290..d539329eaa73abf7c67ccf0cfe175e183f34cbe3 100644 (file)
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -11751,6 +11751,17 @@ m4_set_empty([b], [0], [m4_count(m4_set_list([b]))])
 @end example
 @end defmac
 
+@defmac m4_set_map (@var{set}, @var{action})
+@msindex{set_map}
+For each element in the set @var{set}, expand @var{action} with a single
+argument of the set element.  Behavior is unspecified if @var{action}
+recursively lists the contents of @var{set} (although listing other sets
+is acceptable), or if it modifies the set in any way other than removing
+the element passed as an argument.  This macro is faster than the
+corresponding
+@code{m4_map_args([@var{action}]m4_set_listc([@var{set}]))}.
+@end defmac
+
 @defmac m4_set_remove (@var{set}, @var{value}, @ovar{if-present}, @
  @ovar{if-absent})
 @msindex{set_remove}
@@ -11758,7 +11769,8 @@ If @var{value} is an element in the set @var{set}, then remove it and
 expand @var{if-present}.  Otherwise expand @var{if-absent}.  This macro
 operates in constant time so that multiple removals will scale linearly
 rather than quadratically; but when used outside of
-@code{m4_set_foreach}, it leaves memory occupied until the set is later
+@code{m4_set_foreach} or @code{m4_set_map}, it leaves memory occupied
+until the set is later
 compacted by @code{m4_set_contents} or @code{m4_set_list}.  Several
 other set operations are then less efficient between the time of element
 removal and subsequent memory compaction, but still maintain their

diff --git a/lib/m4sugar/m4sugar.m4 b/lib/m4sugar/m4sugar.m4
index fa01ec6ad616fc303bdefc8b883eea6fb5d14355..2d50230d80bfbcebf9d10a2bd9d76f59235a1f13 100644 (file)
--- a/lib/m4sugar/m4sugar.m4
+++ b/lib/m4sugar/m4sugar.m4
@@ -2717,6 +2717,19 @@ m4_define([m4_set_listc],
          [_m4_set_contents_1])([$1])_m4_set_contents_2([$1],
               [,_m4_defn([_m4_set_($1)])])])
 
+# m4_set_map(SET, ACTION)
+# -----------------------
+# For each element of SET, expand ACTION with a single argument of the
+# current element.  ACTION should not recursively list SET's contents,
+# add elements to SET, nor delete any element from SET except the one
+# passed as an argument.  The order that the elements are visited in
+# is not guaranteed.  This is faster than the corresponding
+#   m4_map_args([ACTION]m4_set_listc([SET]))
+m4_define([m4_set_map],
+[m4_ifdef([_m4_set_cleanup($1)],
+    [_m4_set_contents_1c], [_m4_set_contents_1])([$1])_m4_set_contents_2([$1],
+       [$2(_m4_defn([_m4_set_($1)]))])])
+
 # m4_set_remove(SET, VALUE, [IF-PRESENT], [IF-ABSENT])
 # ----------------------------------------------------
 # If VALUE is an element of SET, delete it and expand IF-PRESENT.
@@ -2726,7 +2739,7 @@ m4_define([m4_set_listc],
 #
 # Optimize if the element being removed is the most recently added,
 # since defining _m4_set_cleanup($1) slows down so many other macros.
-# In particular, this plays well with m4_set_foreach.
+# In particular, this plays well with m4_set_foreach and m4_set_map.
 m4_define([m4_set_remove],
 [m4_set_contains([$1], [$2], [_m4_set_size([$1],
     [m4_decr])m4_if(_m4_defn([_m4_set([$1])]), [$2],

diff --git a/tests/m4sugar.at b/tests/m4sugar.at
index 72b78432be849e4d6fc819a98b3f9a91731caa5e..d6f40a7abd88875849913fc1bc0f057b24dcafe3 100644 (file)
--- a/tests/m4sugar.at
+++ b/tests/m4sugar.at
@@ -1136,7 +1136,8 @@ AT_SETUP([m4@&t@_set])
 AT_KEYWORDS([m4@&t@_set_add m4@&t@_set_add_all m4@&t@_set_contains
 m4@&t@_set_contents m4@&t@_set_delete m4@&t@_set_difference m4@&t@_set_dump
 m4@&t@_set_empty m4@&t@_set_foreach m4@&t@_set_intersection m4@&t@_set_list
-m4@&t@_set_listc m4@&t@_set_remove m4@&t@_set_size m4@&t@_set_union])
+m4@&t@_set_listc m4@&t@_set_map m4@&t@_set_remove m4@&t@_set_size
+m4@&t@_set_union])
 
 # Simple tests
 AT_CHECK_M4SUGAR_TEXT([[m4_set_contains([a], [1], [yes], [no])
@@ -1161,6 +1162,8 @@ m4_set_difference([a], [b])
 m4_set_difference([b], [a])
 m4_set_intersection([a], [b])
 m4_set_union([a], [b])
+m4_define([printodd], [m4_if(m4_eval([$1 & 1]), [1], [:$1])])dnl
+m4_set_map([a], [printodd])
 m4_set_foreach([a], [i], [m4_if(m4_eval(i & 1), [1], [m4_set_remove([a], i)])])
 m4_set_list([a])
 m4_set_add([a], [])
@@ -1196,6 +1199,7 @@ yes
 ,,4
 ,3
 ,1,2,3,,4
+:1:3
 
 2
 
@@ -1259,11 +1263,15 @@ m4_len(m4_set_contents([a]))
 m4_len(m4_set_foreach([b], [b], [m4_if(m4_eval(b & 1), [1],
   [m4_set_remove([b], b, [-])])]))
 m4_set_size([b])
+m4_define([prune3x], [m4_if(m4_eval([$1 % 3]), [0],
+  [m4_set_remove([a], [$1], [-])])])dnl
+m4_len(m4_set_map([a], [prune3x]))
 m4_count(m4_shift(m4_set_intersection([a], [b])))
 ]], [[38894
 5000
 5000
-5000
+3333
+3334
 ]])
 
 AT_CLEANUP