Re: multiline substitutions

[Bruno Haible]

Ralf Wildenhues wrote:
> config.status should be used instead of sed for all the generated
> headers.
> 
> I don't really have time to look into this, but if anyone wants to,
> it seemed fairly easy to do at the time: the only thing missing is
> a cd back to top_builddir and having a relative path to the input and
> output files, then you can use ./config.status --file=- < in > out.

An interesting idea.

Pro:
  - Supports multiline substitution (starting with automake 1.10).
  - Less code to maintain in the module descriptions.
Cons:
  - Slower.

Here are times to create a time.h using a modified rule:
0.05 seconds for the single sed invocation, 0.88 seconds by use of
config.status. The resulting time.h files are identical.

Opinions?

Bruno



--- Makefile.am.old     2010-10-05 23:33:28.000000000 +0200
+++ Makefile.am.new     2010-10-05 23:32:29.000000000 +0200
@@ -166,30 +166,10 @@
 time.h: time.in.h $(CXXDEFS_H) $(ARG_NONNULL_H) $(WARN_ON_USE_H)
        $(AM_V_GEN)rm -f address@hidden $@ && \
        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */' && \
-         sed -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
-             -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
-             -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
-             -e 's|@''NEXT_TIME_H''@|$(NEXT_TIME_H)|g' \
-             -e 's|@''GNULIB_MKTIME''@|$(GNULIB_MKTIME)|g' \
-             -e 's|@''GNULIB_NANOSLEEP''@|$(GNULIB_NANOSLEEP)|g' \
-             -e 's|@''GNULIB_STRPTIME''@|$(GNULIB_STRPTIME)|g' \
-             -e 's|@''GNULIB_TIMEGM''@|$(GNULIB_TIMEGM)|g' \
-             -e 's|@''GNULIB_TIME_R''@|$(GNULIB_TIME_R)|g' \
-             -e 's|@''HAVE_LOCALTIME_R''@|$(HAVE_LOCALTIME_R)|g' \
-             -e 's|@''HAVE_NANOSLEEP''@|$(HAVE_NANOSLEEP)|g' \
-             -e 's|@''HAVE_STRPTIME''@|$(HAVE_STRPTIME)|g' \
-             -e 's|@''HAVE_TIMEGM''@|$(HAVE_TIMEGM)|g' \
-             -e 's|@''REPLACE_LOCALTIME_R''@|$(REPLACE_LOCALTIME_R)|g' \
-             -e 's|@''REPLACE_MKTIME''@|$(REPLACE_MKTIME)|g' \
-             -e 's|@''REPLACE_NANOSLEEP''@|$(REPLACE_NANOSLEEP)|g' \
-             -e 's|@''REPLACE_TIMEGM''@|$(REPLACE_TIMEGM)|g' \
-             -e 
's|@''PTHREAD_H_DEFINES_STRUCT_TIMESPEC''@|$(PTHREAD_H_DEFINES_STRUCT_TIMESPEC)|g'
 \
-             -e 
's|@''SYS_TIME_H_DEFINES_STRUCT_TIMESPEC''@|$(SYS_TIME_H_DEFINES_STRUCT_TIMESPEC)|g'
 \
-             -e 
's|@''TIME_H_DEFINES_STRUCT_TIMESPEC''@|$(TIME_H_DEFINES_STRUCT_TIMESPEC)|g' \
-             -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
+         (cd $(top_builddir) && ./config.status --file=-) < 
$(srcdir)/time.in.h | \
+         sed -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
              -e '/definition of _GL_ARG_NONNULL/r $(ARG_NONNULL_H)' \
-             -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \
-             < $(srcdir)/time.in.h; \
+             -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)'; \
        } > address@hidden && \
        mv address@hidden $@
 MOSTLYCLEANFILES += time.h time.h-t


$ time make time.h
rm -f time.h-t time.h && \
        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */' && \
          sed -e 's|@''INCLUDE_NEXT''@|include_next|g' \
              -e 's|@''PRAGMA_SYSTEM_HEADER''@|#pragma GCC system_header|g' \
              -e 's|@''PRAGMA_COLUMNS''@||g' \
              -e 's|@''NEXT_TIME_H''@|<time.h>|g' \
              -e 's|@''GNULIB_MKTIME''@|0|g' \
              -e 's|@''GNULIB_NANOSLEEP''@|0|g' \
              -e 's|@''GNULIB_STRPTIME''@|0|g' \
              -e 's|@''GNULIB_TIMEGM''@|0|g' \
              -e 's|@''GNULIB_TIME_R''@|0|g' \
              -e 's|@''HAVE_LOCALTIME_R''@|1|g' \
              -e 's|@''HAVE_NANOSLEEP''@|1|g' \
              -e 's|@''HAVE_STRPTIME''@|1|g' \
              -e 's|@''HAVE_TIMEGM''@|1|g' \
              -e 's|@''REPLACE_LOCALTIME_R''@|GNULIB_PORTCHECK|g' \
              -e 's|@''REPLACE_MKTIME''@|GNULIB_PORTCHECK|g' \
              -e 's|@''REPLACE_NANOSLEEP''@|GNULIB_PORTCHECK|g' \
              -e 's|@''REPLACE_TIMEGM''@|GNULIB_PORTCHECK|g' \
              -e 's|@''PTHREAD_H_DEFINES_STRUCT_TIMESPEC''@|0|g' \
              -e 's|@''SYS_TIME_H_DEFINES_STRUCT_TIMESPEC''@|0|g' \
              -e 's|@''TIME_H_DEFINES_STRUCT_TIMESPEC''@|1|g' \
              -e '/definitions of _GL_FUNCDECL_RPL/r c++defs.h' \
              -e '/definition of _GL_ARG_NONNULL/r arg-nonnull.h' \
              -e '/definition of _GL_WARN_ON_USE/r warn-on-use.h' \
              < ./time.in.h; \
        } > time.h-t && \
        mv time.h-t time.h

real    0m0.050s
user    0m0.036s
sys     0m0.016s


$ time make time.h
rm -f time.h-t time.h && \
        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */' && \
          (cd .. && ./config.status --file=-) < ./time.in.h | \
          sed -e '/definitions of _GL_FUNCDECL_RPL/r c++defs.h' \
              -e '/definition of _GL_ARG_NONNULL/r arg-nonnull.h' \
              -e '/definition of _GL_WARN_ON_USE/r warn-on-use.h'; \
        } > time.h-t && \
        mv time.h-t time.h

real    0m0.882s
user    0m0.264s
sys     0m0.628s