diagnostics: use gnulib's libtextstyle-optional

Bruno Haible just added a default implementation of libtextstyle's
interface when the library is not available.
https://lists.gnu.org/archive/html/bison-patches/2019-03/msg00025.html

* gnulib: Update.
* bootstrap.conf: Replace libtextstyle with libtextstyle-optional.
* src/complain.c, src/getargs.c: Remove now useless cpp guards.

NEWS

@@ -10,6 +10,34 @@ GNU Bison NEWS
 
 ** New features
 
+*** Colored diagnostics
+
+  As an experimental feature, Bison now generates colored diagnostics,
+  controlled by the new options --color and --style.
+
+  Install the libtextstyle library before configuring Bison to use them.
+  It is available from
+
+    https://alpha.gnu.org/gnu/gettext/
+
+  for instance
+
+    https://alpha.gnu.org/gnu/gettext/libtextstyle-0.7.tar.gz
+
+  The option --color supports the following arguments:
+    - always, yes: Enable colors.
+    - never, no: Disable colors.
+    - auto, tty (default): Enable colors if the output device is a tty.
+
+  To customize the styles, create a CSS file similar to
+
+    /* black-and-white.css */
+    .warning   { }
+    .error     { font-weight: 800; text-decoration: underline; }
+    .note      { }
+
+  then invoke bison with --style=black-and-white.css.
+
 *** Disabling output
 
   When given -fsyntax-only, the diagnostics are reported, but no output is

bootstrap.conf

@@ -28,7 +28,7 @@ gnulib_modules='
   gpl-3.0 hash inttypes isnan javacomp-script
   javaexec-script
   ldexpl
-  libtextstyle
+  libtextstyle-optional
   malloc-gnu
   mbswidth
   non-recursive-gnulib-prefix-hack

data/diagnostics.css

@@ -1,3 +1,8 @@
-.warning   { color : purple; }
-.error     { color : red; }
-.note      { color : cyan; }
+/* CSS style for Bison's diagnostics.
+
+   This is an experimental feature.  The class names may change in the
+   future.  */
+
+.warning   { color: purple; }
+.error     { color: red; }
+.note      { color: cyan; }

lib/.gitignore

@@ -319,3 +319,5 @@
 /rmdir.c
 /same-inode.h
 /assure.h
+/fsync.c
+/textstyle.in.h

m4/.gitignore

@@ -5,6 +5,8 @@
 /asm-underscore.m4
 /assert.m4
 /calloc.m4
+/canonicalize.m4
+/clock_time.m4
 /close-stream.m4
 /close.m4
 /closeout.m4
@@ -36,19 +38,26 @@
 /frexpl.m4
 /fseterr.m4
 /fstat.m4
+/fsync.m4
 /getdtablesize.m4
+/gethrxtime.m4
 /getopt.m4
 /getprogname.m4
+/getrusage.m4
 /gettext.m4
+/gettime.m4
+/gettimeofday.m4
 /glibc2.m4
 /glibc21.m4
 /gnulib-cache.m4
 /gnulib-common.m4
 /gnulib-comp.m4
 /gnulib-tool.m4
+/host-cpu-c-abi.m4
 /iconv.m4
 /include_next.m4
 /intdiv0.m4
+/intl-thread-locale.m4
 /intl.m4
 /intldir.m4
 /intlmacosx.m4
@@ -70,12 +79,15 @@
 /lib-ld.m4
 /lib-link.m4
 /lib-prefix.m4
+/libtextstyle-optional.m4
+/libtextstyle.m4
 /libunistring-base.m4
 /limits-h.m4
 /localcharset.m4
 /locale-fr.m4
 /locale-ja.m4
 /locale-zh.m4
+/localtime-buffer.m4
 /lock.m4
 /longlong.m4
 /lstat.m4
@@ -117,9 +129,15 @@
 /quotearg.m4
 /raise.m4
 /rawmemchr.m4
+/readlink.m4
 /realloc.m4
+/relocatable-lib.m4
+/relocatable.m4
+/rename.m4
+/rmdir.m4
 /sched_h.m4
 /setenv.m4
+/sh-filename.m4
 /sig_atomic_t.m4
 /sigaction.m4
 /signal_h.m4
@@ -132,7 +150,9 @@
 /spawn_h.m4
 /sprintf-posix.m4
 /ssize_t.m4
+/stat-time.m4
 /stat.m4
+/std-gnu11.m4
 /stdbool.m4
 /stddef_h.m4
 /stdint.m4
@@ -148,12 +168,16 @@
 /strndup.m4
 /strnlen.m4
 /strverscmp.m4
+/sys_resource_h.m4
 /sys_socket_h.m4
 /sys_stat_h.m4
+/sys_time_h.m4
+/sys_times_h.m4
 /sys_types_h.m4
 /sys_wait_h.m4
 /threadlib.m4
 /time_h.m4
+/timespec.m4
 /uintmax_t.m4
 /unistd-safer.m4
 /unistd_h.m4
@@ -177,25 +201,3 @@
 /xalloc.m4
 /xsize.m4
 /xstrndup.m4
-/host-cpu-c-abi.m4
-/stat-time.m4
-/sys_time_h.m4
-/sys_times_h.m4
-/sh-filename.m4
-/clock_time.m4
-/gethrxtime.m4
-/getrusage.m4
-/gettime.m4
-/gettimeofday.m4
-/localtime-buffer.m4
-/sys_resource_h.m4
-/timespec.m4
-/intl-thread-locale.m4
-/canonicalize.m4
-/readlink.m4
-/relocatable-lib.m4
-/relocatable.m4
-/libtextstyle.m4
-/rename.m4
-/rmdir.m4
-/std-gnu11.m4

src/complain.c

@@ -23,13 +23,10 @@
 #include "system.h"
 
 #include <argmatch.h>
-#include <stdarg.h>
 #include <progname.h>
+#include <stdarg.h>
 #include <sys/stat.h>
-
-#if HAVE_LIBTEXTSTYLE
-# include <textstyle.h>
-#endif
+#include <textstyle.h>
 
 #include "complain.h"
 #include "files.h"
@@ -68,41 +65,33 @@ static severity warnings_flag[warnings_size];
 
 static unsigned *indent_ptr = NULL;
 
-#if HAVE_LIBTEXTSTYLE
 styled_ostream_t errstream = NULL;
-#endif
 
 void
-begin_use_class (const char *s _GL_UNUSED, FILE *out _GL_UNUSED)
+begin_use_class (const char *s, FILE *out)
 {
-#if HAVE_LIBTEXTSTYLE
   if (out == stderr)
     {
       styled_ostream_begin_use_class (errstream, s);
       styled_ostream_flush_to_current_style (errstream);
     }
-#endif
 }
 
 void
-end_use_class (const char *s _GL_UNUSED, FILE *out _GL_UNUSED)
+end_use_class (const char *s, FILE *out)
 {
-#if HAVE_LIBTEXTSTYLE
   if (out == stderr)
     {
       styled_ostream_end_use_class (errstream, s);
       styled_ostream_flush_to_current_style (errstream);
     }
-#endif
 }
 
 void
-flush (FILE *out _GL_UNUSED)
+flush (FILE *out)
 {
-#if HAVE_LIBTEXTSTYLE
   if (out == stderr)
     ostream_flush (errstream, FLUSH_THIS_STREAM);
-#endif
   fflush (out);
 }
 
@@ -267,10 +256,11 @@ complain_init_color (void)
   else
     /* No styling.  */
     style_file_name = NULL;
+#endif
+
   errstream =
     styled_ostream_create (STDERR_FILENO, "(stderr)", TTYCTL_AUTO,
                            style_file_name);
-#endif
 }
 
 void

src/getargs.c

@@ -30,10 +30,7 @@
 #include <getopt.h>
 #include <progname.h>
 #include <quote.h>
-
-#if HAVE_LIBTEXTSTYLE
-# include <textstyle.h>
-#endif
+#include <textstyle.h>
 
 #include "complain.h"
 #include "files.h"
@@ -590,7 +587,6 @@ command_line_location (void)
 static void
 getargs_colors (int argc _GL_UNUSED, char *argv[] _GL_UNUSED)
 {
-#if HAVE_LIBTEXTSTYLE
   for (int i = 1; i < argc; i++)
     {
       const char *arg = argv[i];
@@ -600,7 +596,6 @@ getargs_colors (int argc _GL_UNUSED, char *argv[] _GL_UNUSED)
         handle_style_option (arg + strlen ("--style="));
     }
   complain_init_color ();
-#endif
 }