diagnostics: check the styling

Enable checking of styles even when libtextstyle is not installed.

* src/getargs.h, src/getargs.c (style_debug): New.
(getargs_colors): Set it when --style=debug.
* src/complain.c (begin_use_class, end_use_class): Use it.
* tests/diagnostics.at: New.

src/complain.c

@@ -72,8 +72,13 @@ begin_use_class (const char *s, FILE *out)
 {
   if (out == stderr)
     {
-      styled_ostream_begin_use_class (errstream, s);
-      styled_ostream_flush_to_current_style (errstream);
+      if (style_debug)
+        fprintf (out, "<%s>", s);
+      else
+        {
+          styled_ostream_begin_use_class (errstream, s);
+          styled_ostream_flush_to_current_style (errstream);
+        }
     }
 }
 
@@ -82,8 +87,13 @@ end_use_class (const char *s, FILE *out)
 {
   if (out == stderr)
     {
-      styled_ostream_end_use_class (errstream, s);
-      styled_ostream_flush_to_current_style (errstream);
+      if (style_debug)
+        fprintf (out, "</%s>", s);
+      else
+        {
+          styled_ostream_end_use_class (errstream, s);
+          styled_ostream_flush_to_current_style (errstream);
+        }
     }
 }
 

src/getargs.c

@@ -45,6 +45,7 @@ bool no_lines_flag = false;
 bool token_table_flag = false;
 location yacc_loc = EMPTY_LOCATION_INIT;
 bool update_flag = false; /* for -u */
+bool style_debug = false; /* --style=debug. */
 
 bool nondeterministic_parser = false;
 bool glr_parser = false;
@@ -595,7 +596,13 @@ getargs_colors (int argc, char *argv[])
       if (STRPREFIX_LIT ("--color=", arg))
         handle_color_option (arg + strlen ("--color="));
       else if (STRPREFIX_LIT ("--style=", arg))
-        handle_style_option (arg + strlen ("--style="));
+        {
+          const char *style = arg + strlen ("--style=");
+          if (STREQ (style, "debug"))
+            style_debug = true;
+          else
+            handle_style_option (style);
+        }
     }
   complain_init_color ();
 }

src/getargs.h

@@ -41,7 +41,7 @@ extern bool no_lines_flag;              /* for -l */
 extern bool token_table_flag;           /* for -k */
 extern location yacc_loc;               /* for -y */
 extern bool update_flag;                /* for -u */
-
+extern bool style_debug;                /* --style=debug. */
 /* GLR_PARSER is true if the input file says to use the GLR
    (Generalized LR) parser, and to output some additional information
    used by the GLR algorithm.  */