m4: use a safer pattern to enable/disable output

Work on some other areas of Bison revealed that some macros expanded
to be expanded only once were actually expanded several times.  This
was due to the fact that changecom was not properly restored each
time, and macro names appearing in comments were then expanded.

Introduce begin/end macros which are easier to match that
changecom()/changecom(#).

* data/bison.m4 (b4_output_begin, b4_output_end): New.
* data/glr.c, data/glr.cc, data/lalr1.cc, data/lalr1.java,
* data/location.cc, data/stack.hh, data/yacc.c:
Use them.

diff --git a/data/bison.m4 b/data/bison.m4
index fac86f2a0132f8e0d67507dc0e77671023f3a7f2..a24b162c8177796415cfd297f0a8ec5a951e96e0 100644 (file)
--- a/data/bison.m4
+++ b/data/bison.m4
@@ -58,6 +58,30 @@ This special exception was added by the Free Software Foundation in
 version 2.2 of Bison.])])
 
 
 version 2.2 of Bison.])])
 
 

+## -------- ##
+## Output.  ##
+## -------- ##
+
+# b4_output_begin(FILE)
+# ---------------------
+# Enable output, i.e., send to diversion 0, expand after "#", and
+# generate the tag to output into FILE.  Must be followed by EOL.
+m4_define([b4_output_begin],
+[m4_changecom()
+m4_divert_push(0)dnl
+@output(m4_unquote([$1])@)@dnl
+])
+
+
+# b4_output_end()
+# ---------------
+# Output nothing, restore # as comment character (no expansions after #).
+m4_define([b4_output_end],
+[m4_divert_pop(0)
+m4_changecom([#])
+])
+
+

 ## ---------------- ##
 ## Error handling.  ##
 ## ---------------- ##
 ## ---------------- ##
 ## Error handling.  ##
 ## ---------------- ##

diff --git a/data/glr.c b/data/glr.c
index b6aa545c53b702a753eee228be31ec406e492381..cdefd5070e06dd6b3e6d373ec5a0ed18c0938fb0 100644 (file)
--- a/data/glr.c
+++ b/data/glr.c
@@ -179,13 +179,10 @@ m4_define([b4_shared_declarations],
 ## Output files.  ##
 ## -------------- ##
 
 ## Output files.  ##
 ## -------------- ##
 

-# We do want M4 expansion after # for CPP macros.
-m4_changecom()
-m4_divert_push(0)dnl
-@output(b4_parser_file_name@)@
+b4_output_begin([b4_parser_file_name])

 b4_copyright([Skeleton implementation for Bison GLR parsers in C],
 b4_copyright([Skeleton implementation for Bison GLR parsers in C],

-             [2002-2012])
-[
+             [2002-2012])[
+

 /* C GLR parser skeleton written by Paul Hilfinger.  */
 
 ]b4_identification
 /* C GLR parser skeleton written by Paul Hilfinger.  */
 
 ]b4_identification


@@ -2571,17 +2568,17 @@ yypdumpstack (yyGLRStack* yystackp)
 }
 #endif
 ]b4_epilogue[]dnl
 }
 #endif
 ]b4_epilogue[]dnl

-dnl
-dnl glr.cc produces its own header.
-dnl
+b4_output_end()
+
+# glr.cc produces its own header.

 m4_if(b4_skeleton, ["glr.c"],
 [b4_defines_if(
 m4_if(b4_skeleton, ["glr.c"],
 [b4_defines_if(

-[@output(b4_spec_defines_file@)@
+[b4_output_begin([b4_spec_defines_file])

 b4_copyright([Skeleton interface for Bison GLR parsers in C],
              [2002-2012])[
 
 ]b4_cpp_guard_open([b4_spec_defines_file])[
 ]b4_shared_declarations[
 ]b4_cpp_guard_close([b4_spec_defines_file])[
 b4_copyright([Skeleton interface for Bison GLR parsers in C],
              [2002-2012])[
 
 ]b4_cpp_guard_open([b4_spec_defines_file])[
 ]b4_shared_declarations[
 ]b4_cpp_guard_close([b4_spec_defines_file])[

-]])])dnl
-m4_divert_pop(0)
+]b4_output_end()
+])])

diff --git a/data/glr.cc b/data/glr.cc
index 0e53d61915833343458c5c49022fb35a397c0e3a..49b4fa1079a5b69b90e34d05d5a14ccf4cebfb3d 100644 (file)
--- a/data/glr.cc
+++ b/data/glr.cc
@@ -230,8 +230,7 @@ m4_defn([b4_parse_param]))],
 m4_include(b4_pkgdatadir/[glr.c])
 m4_popdef([b4_parse_param])
 
 m4_include(b4_pkgdatadir/[glr.c])
 m4_popdef([b4_parse_param])
 

-m4_divert_push(0)
-@output(b4_spec_defines_file@)@
+b4_output_begin([b4_spec_defines_file])

 b4_copyright([Skeleton interface for Bison GLR parsers in C++],
              [2002-2006, 2009-2012])[
 
 b4_copyright([Skeleton interface for Bison GLR parsers in C++],
              [2002-2006, 2009-2012])[
 


@@ -344,4 +343,4 @@ b4_percent_define_flag_if([[global_tokens_and_yystype]],
 ]b4_namespace_close[
 ]b4_percent_code_get([[provides]])[
 ]b4_cpp_guard_close([b4_spec_defines_file])[
 ]b4_namespace_close[
 ]b4_percent_code_get([[provides]])[
 ]b4_cpp_guard_close([b4_spec_defines_file])[

-]m4_divert_pop(0)
+]b4_output_end()

diff --git a/data/lalr1.cc b/data/lalr1.cc
index e45b2e1f860cf48ff9c66be677b5f20001008240..237b246f5be6490e7393028c86f425d1b57fc4c5 100644 (file)
--- a/data/lalr1.cc
+++ b/data/lalr1.cc
@@ -30,11 +30,8 @@ b4_percent_define_ifdef([[api.location.type]], [],
   m4_include(b4_pkgdatadir/[location.cc])])
 m4_include(b4_pkgdatadir/[stack.hh])
 
   m4_include(b4_pkgdatadir/[location.cc])])
 m4_include(b4_pkgdatadir/[stack.hh])
 

-# We do want M4 expansion after # for CPP macros.
-m4_changecom()
-m4_divert_push(0)dnl

 b4_defines_if(
 b4_defines_if(

-[@output(b4_spec_defines_file@)@
+[b4_output_begin([b4_spec_defines_file])

 b4_copyright([Skeleton interface for Bison LALR(1) parsers in C++],
              [2002-2012])
 [
 b4_copyright([Skeleton interface for Bison LALR(1) parsers in C++],
              [2002-2012])
 [


@@ -265,8 +262,11 @@ b4_user_stype
 ])[
 ]b4_percent_code_get([[provides]])[
 ]b4_cpp_guard_close([b4_spec_defines_file])
 ])[
 ]b4_percent_code_get([[provides]])[
 ]b4_cpp_guard_close([b4_spec_defines_file])

-])dnl
-@output(b4_parser_file_name@)@
+b4_output_end()
+])
+
+
+b4_output_begin([b4_parser_file_name])

 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in C++],
              [2002-2012])
 b4_percent_code_get([[top]])[]dnl
 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in C++],
              [2002-2012])
 b4_percent_code_get([[top]])[]dnl


@@ -1140,4 +1140,4 @@ b4_error_verbose_if([int yystate, int yytoken],
 
 ]b4_namespace_close[
 ]b4_epilogue[]dnl
 
 ]b4_namespace_close[
 ]b4_epilogue[]dnl

-m4_divert_pop(0)
+b4_output_end()

diff --git a/data/lalr1.java b/data/lalr1.java
index d1410a10cf806b6598d71e90c44bc1d38a1e22a5..e961fc5b450f56a1d3a3ac31eede13b713b8205c 100644 (file)
--- a/data/lalr1.java
+++ b/data/lalr1.java
@@ -22,8 +22,7 @@ m4_ifval(m4_defn([b4_symbol_destructors]),
         [b4_fatal([%s: %%destructor does not make sense in Java], [b4_skeleton])],
         [])
 
         [b4_fatal([%s: %%destructor does not make sense in Java], [b4_skeleton])],
         [])
 

-m4_divert_push(0)dnl
-@output(b4_parser_file_name@)@
+b4_output_begin([b4_parser_file_name])

 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in Java],
              [2007-2012])
 
 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in Java],
              [2007-2012])
 


@@ -925,4 +924,4 @@ b4_percent_code_get[]dnl
 }
 
 b4_epilogue
 }
 
 b4_epilogue

-m4_divert_pop(0)dnl
+b4_output_end()

diff --git a/data/location.cc b/data/location.cc
index 49f5f349534d67d3d64c178e4e94728b7a50d5df..58182a34acfe048966e8998eb29d1327ed9df45e 100644 (file)
--- a/data/location.cc
+++ b/data/location.cc
@@ -15,10 +15,8 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 

-# We do want M4 expansion after # for CPP macros.
-m4_changecom()
-m4_divert_push(0)dnl
-@output(b4_dir_prefix[]position.hh@)@
+
+b4_output_begin([b4_dir_prefix[]position.hh])

 b4_copyright([Positions for Bison parsers in C++],
              [2002-2007, 2009-2012])[
 
 b4_copyright([Positions for Bison parsers in C++],
              [2002-2007, 2009-2012])[
 


@@ -148,7 +146,10 @@ b4_copyright([Positions for Bison parsers in C++],
 
 ]b4_namespace_close[
 ]b4_cpp_guard_close([b4_dir_prefix[]position.hh])
 
 ]b4_namespace_close[
 ]b4_cpp_guard_close([b4_dir_prefix[]position.hh])

-@output(b4_dir_prefix[]location.hh@)@
+b4_output_end()
+
+
+b4_output_begin([b4_dir_prefix[]location.hh])

 b4_copyright([Locations for Bison parsers in C++],
              [2002-2007, 2009-2012])[
 
 b4_copyright([Locations for Bison parsers in C++],
              [2002-2007, 2009-2012])[
 


@@ -292,5 +293,4 @@ b4_copyright([Locations for Bison parsers in C++],
 ]b4_namespace_close[
 
 ]b4_cpp_guard_close([b4_dir_prefix[]location.hh])
 ]b4_namespace_close[
 
 ]b4_cpp_guard_close([b4_dir_prefix[]location.hh])

-m4_divert_pop(0)
-m4_changecom([#])
+b4_output_end()

diff --git a/data/stack.hh b/data/stack.hh
index ddedc79bef7d25e1415f0f4345043fd8a6b98901..ab1049c184d4f111513e6bb33ecb00f8b888bab9 100644 (file)
--- a/data/stack.hh
+++ b/data/stack.hh
@@ -18,10 +18,7 @@
 m4_pushdef([b4_copyright_years],
            [2002-2012])
 
 m4_pushdef([b4_copyright_years],
            [2002-2012])
 

-# We do want M4 expansion after # for CPP macros.
-m4_changecom()
-m4_divert_push(0)dnl
-@output(b4_dir_prefix[]stack.hh@)@
+b4_output_begin([b4_dir_prefix[]stack.hh])

 b4_copyright([Stack handling for Bison parsers in C++],
              [2002-2012])[
 
 b4_copyright([Stack handling for Bison parsers in C++],
              [2002-2012])[
 


@@ -119,6 +116,6 @@ b4_copyright([Stack handling for Bison parsers in C++],
 ]b4_namespace_close[
 
 ]b4_cpp_guard_close([b4_dir_prefix[]stack.hh])
 ]b4_namespace_close[
 
 ]b4_cpp_guard_close([b4_dir_prefix[]stack.hh])

-m4_divert_pop(0)
-m4_popdef([b4_copyright_years])dnl
-m4_changecom([#])
+b4_output_end()
+
+m4_popdef([b4_copyright_years])

diff --git a/data/yacc.c b/data/yacc.c
index 0f3155234fdf9c82e7721367e94a599d61e6fb35..810e2b21a0726c8544433e37a1160c6adf477c93 100644 (file)
--- a/data/yacc.c
+++ b/data/yacc.c
@@ -326,14 +326,12 @@ m4_define([b4_shared_declarations],
 ]b4_cpp_guard_close([b4_spec_defines_file])[]dnl
 ])
 
 ]b4_cpp_guard_close([b4_spec_defines_file])[]dnl
 ])
 

+

 ## -------------- ##
 ## Output files.  ##
 ## -------------- ##
 
 ## -------------- ##
 ## Output files.  ##
 ## -------------- ##
 

-# We do want M4 expansion after # for CPP macros.
-m4_changecom()
-m4_divert_push(0)dnl
-@output(b4_parser_file_name@)@
+b4_output_begin([b4_parser_file_name])

 b4_copyright([Bison implementation for Yacc-like parsers in C],
              [1984, 1989-1990, 2000-2012])[
 
 b4_copyright([Bison implementation for Yacc-like parsers in C],
              [1984, 1989-1990, 2000-2012])[
 


@@ -2052,11 +2050,13 @@ yypushreturn:]])[
 
 
 ]b4_epilogue[]dnl
 
 
 ]b4_epilogue[]dnl

+b4_output_end()
+

 b4_defines_if(
 b4_defines_if(

-[@output(b4_spec_defines_file@)@
-b4_copyright([Bison interface for Yacc-like parsers in C],
-             [1984, 1989-1990, 2000-2012])[
+[b4_output_begin([b4_spec_defines_file])[
+]b4_copyright([Bison interface for Yacc-like parsers in C],
+              [1984, 1989-1990, 2000-2012])[

 
 ]b4_shared_declarations[
 
 ]b4_shared_declarations[

-]])dnl b4_defines_if
-m4_divert_pop(0)
+]b4_output_end()
+])