Fix empty argument handling.

* m4/Makefile (install): Add dnl after changequote
* m4/kwargs.m4: Divert everything to -1.
(KWARG_SET): Tolerate empty argument.
(m4_kwargs_parse): Don't stop on empty arguments.
(KWARGS_DUMP): Change arguments.
(KWARGS_LIST): New macro.
* t/define.t: Reflect changes to KWARGS_DUMP.
* t/dump.t: Likewise.
* t/null.t: Likewise.

6 files changed, 50 insertions, 24 deletions

diff --git a/README b/README
index 27476c4..63d662f 100644
--- a/README
+++ b/README
@@ -109,9 +109,12 @@ by category.
 Debugging
 ---------
 
-KWARGS_DUMP([PREFIX])
-  Dump all keyword arguments to stdout, each on a separate line, prefixed
-  with PREFIX.
+KWARGS_DUMP([DELIM],[EXP])
+  For each defined keyword argument, produce the following expansion:
+  
+    EXP(`KW=VAL')DELIM
+    
+  DELIM defaults to newline, EXP - to m4_quote, 
 
 Keyword arguments access macros
 -------------------------------
@@ -140,6 +143,10 @@ KWARGS_FOREACH(ITERATOR, TEXT)
   TEXT is appended to the expansion of KWARGS_FOREACH. TEXT may refer to
   ITERATOR. Any definition of ITERATOR prior to this invocation is restored.
 
+KWARGS_LIST()
+  Expand to a comma-delimited list of quoted keyword arguments, suitable for
+  use as argument list to a macro.
+
 Expansion in keyword argument context
 -------------------------------------
 
diff --git a/m4/Makefile b/m4/Makefile
index 0db042f..4333402 100644
--- a/m4/Makefile
+++ b/m4/Makefile
@@ -14,7 +14,7 @@ install:
 	if test "$(BRACKETQUOTES)" -eq 1; then \
 	    for file in $(SOURCES); do \
 	        cat $$file | tr \`\' '[]' | \
-                   sed 's/^dnl bracketquotes/changequote([,])/' \
+                   sed 's/^dnl bracketquotes/changequote([,])dnl/' \
                       > $(DESTDIR)$(M4DIR)/$$file;\
 	    done;\
 	else \
diff --git a/m4/kwargs.m4 b/m4/kwargs.m4
index 982fc44..a0d6f1a 100644
--- a/m4/kwargs.m4
+++ b/m4/kwargs.m4
@@ -13,11 +13,11 @@ dnl GNU General Public License for more details.
 dnl
 dnl You should have received a copy of the GNU General Public License
 dnl along with M4KWARGS.  If not, see <http://www.gnu.org/licenses/>.
-pushdef(`__diversion__',divnum)divert(-1)
-
+dnl
 dnl The 'bracketquotes' comment line will be replaced by make install
 dnl with the appropriate changequote statement, if required.
 dnl bracketquotes
+pushdef(`__diversion__',divnum)divert(-1)
 
 dnl Determine whether the patsubst builtin is available and whether it
 dnl takes an extended regular expression as its second argument.
@@ -94,12 +94,13 @@ m4_define(`_m4_kwargs_list')
 # -------------------------
 # Sets argument NAME to VALUE
 m4_define(`KWARG_SET',
+`m4_ifelse(`$1',`',,
 `m4_pushdef(`__opt_name__',m4_dquote(m4_kwargs_mangle_name(`$1')))m4_dnl
 m4_kwargs_list_if_member(`_m4_kwargs_list',`$1',`m4_popdef(__opt_name__)',
 `m4_define(`_m4_kwargs_list',m4_ifempty(m4_quote(_m4_kwargs_list),
 m4_dquote(m4_dquote(`$1')),`m4_quote(m4_dquote(_m4_kwargs_list), m4_dquote(`$1'))'))')m4_dnl
 m4_pushdef(__opt_name__,`$2')m4_dnl
-m4_popdef(`__opt_name__')')
+m4_popdef(`__opt_name__')')')
 
 # KWARG_CLR(NAME)
 # ---------------
@@ -197,17 +198,28 @@ m4_popdef(`_m4_kwargs_list')')
 m4_define(`KWARGS_FOREACH',
   `m4_foreach(`$1',m4_quote_names(_m4_kwargs_list),`$2')')
 
-# KWARGS_DUMP([PREFIX])
+# KWARGS_DUMP([DELIM],[EXP])
 # ---------------------
-# Dump all keyword arguments to stdout, each on a separate line, prefixed
-# with PREFIX.
-#
+# For each defined keyword argument, expand to
+#   `KW=VAL'DELIM
+# If EXP is supplied, expand to
+#   EXP(`KW=VAL')DELIM
+# instead.
+# Default DELIM is newline.
 m4_define(`KWARGS_DUMP',
-`m4_pushdef(`__dump_newline__')m4_dnl
-KWARGS_FOREACH(`_GR_Arg',`m4_ifelse(__dump_newline__,,,`
-')m4_define(`__dump_newline__',1)m4_dnl
-`$1'_GR_Arg=KWARG_VALUE(_GR_Arg)')m4_dnl
-m4_popdef(`__dump_newline__')')
+ `_$0(`m4_ifelse(`$1',,`
+',`$1')',`m4_ifelse(`$2',`',`m4_quote',`$2')',_m4_kwargs_list)')
+
+m4_define(`_KWARGS_DUMP',
+ `m4_ifelse(`$3',,,
+  `m4_quote($2(`$3'=KWARG_VALUE(`$3')))_$0(`$1',`$2',m4_shift(m4_shift(m4_shift($@))))')')
+
+# _KWARGS_DUMP(DELIM,EXP,ARGS...)
+m4_define(`__KWARGS_DUMP',
+ `m4_ifelse(`$3',,,
+   `$1_KWARGS_DUMP($@)')')
+
+m4_define(`KWARGS_LIST',`KWARGS_DUMP(`,')')
 
 m4_define(`KW_ARG_1',`$1')
 m4_define(`KW_ARG_2',`$2')
@@ -246,8 +258,8 @@ m4_define(`KWARGS_WITH',
 `m4_pushdef(`__call__',`$1')KWARGS_APPLY(`__call__',m4_shift($@))m4_popdef(`__call__')')
 
 m4_define(`m4_kwargs_parse',
-`m4_ifelse(`$1',`',`',
- `m4_ifelse(m4_index(`$1',`='),-1,`,``$1''`'m4_kwargs_parse(m4_shift($@))',`KWARGS_ASGN($@)')')')
+`m4_ifelse(`$#',`0',`',m4_index(`$1',`='),-1,`,``$1''`'_m4_kwargs_parse($@)',`KWARGS_ASGN($@)')')
+m4_define(`_m4_kwargs_parse',`m4_ifelse(`$#',1,`',`m4_kwargs_parse(m4_shift($@))')')
 
 # KWARGS_DEFINE(NAME,TEXT)
 # ------------------------
diff --git a/t/define.t b/t/define.t
index dad6f6b..81a77fe 100644
--- a/t/define.t
+++ b/t/define.t
@@ -21,7 +21,8 @@ argv[1]=KW_ARGV(1)
 argc=KW_ARGC
 arg@=KW_ARGQ
 y=KWARG_VALUE(y)
-KWARGS_DUMP(: )')m4_dnl
+dump:
+KWARGS_DUMP()')m4_dnl
 # EXPAND
 FOO(a,`b,x',c,x=4,y=`5,67',a=5)
 # END
@@ -33,8 +34,9 @@ argv[1]=a
 argc=3
 arg@=`a',`b,x',`c'
 y=5,67
-: x=4
-: y=5,67
-: a=5
+dump:
+x=4
+y=5,67
+a=5
 # END
 !END
diff --git a/t/dump.t b/t/dump.t
index 82492fe..c3488c9 100644
--- a/t/dump.t
+++ b/t/dump.t
@@ -19,12 +19,17 @@ m4_define(`_m4_kwargs_list',``foo',`bar',`baz'')m4_dnl
 m4_pushdef(`--foo',`1')
 m4_pushdef(`--bar',`Bar')
 m4_pushdef(`--baz',`Baz qux')
+m4_define(`printarg',`// `$1'')
 m4_divert(0)m4_dnl
 // BEGIN
-KWARGS_DUMP(`// ')
+KWARGS_DUMP()
+KWARGS_DUMP(,`printarg')
 // END
 !OUT
 // BEGIN
+foo=1
+bar=Bar
+baz=Baz qux
 // foo=1
 // bar=Bar
 // baz=Baz qux
diff --git a/t/null.t b/t/null.t
index e12ba44..8a1ddcc 100644
--- a/t/null.t
+++ b/t/null.t
@@ -15,7 +15,7 @@
 !C along with M4KWARGS.  If not, see <http://www.gnu.org/licenses/>.
 !IN
 # BEGIN
-KWARGS_DUMP(`# ')
+KWARGS_DUMP()
 # END
 !OUT
 # BEGIN