errors: support indented context info in m4 macros

* TODO: Address the issue, so remove it.
* data/bison.m4: Use b4_error with [[note]] rather than a complain_at
for context information.
* src/complain.c (complain_args): Take an additional argument, an
indentation pointer, to allow the dispatching of context information.
* src/complain.h (complain_args): Adjust prototype.
* src/scan-skel.l (at_directive_perform): Recognize the new @note mark.
* tests/input.at: Adjust.

Signed-off-by: Akim Demaille <akim@lrde.epita.fr>

TODO

@@ -1,8 +1,4 @@
 * Short term
-** erroneous test
-src/complains.c changed the output of errors (prefixes), but the m4 macros
-have not been changed to reflect this change.
-Fix the message "an identifier expected" (m4) in tests/input.at.
 
 ** push-parser
 Check it too when checking the different kinds of parsers.  And be

data/bison.m4

@@ -743,7 +743,7 @@ m4_define([_b4_percent_define_check_values],
                          [$1],
                          m4_dquote(m4_indir([b4_percent_define(]$1[)])))
           m4_foreach([b4_value], m4_dquote(m4_shift($@)),
-                     [b4_complain_at(b4_percent_define_get_loc([$1]),
+                     [b4_error([[note]], b4_percent_define_get_loc([$1]), []
                                      [[accepted value: '%s']],
                                      m4_dquote(b4_value))])])dnl
    m4_popdef([b4_good_value])],

src/complain.c

@@ -120,11 +120,9 @@ error_message (const location *loc, warnings flags, const char *prefix,
 
 /** Raise a complaint. That can be a fatal error, a complaint or just a
     warning.  */
-
 static inline void
 complains (const location *loc, warnings flags, const char *message,
            va_list args)
-
 {
   const char* prefix =
     flags & fatal ? _("fatal error")
@@ -159,24 +157,26 @@ complain_indent (location const *loc, warnings flags, unsigned *indent,
 }
 
 void
-complain_args (location const *loc, warnings w, int argc, char *argv[])
+complain_args (location const *loc, warnings w, unsigned *indent,
+               int argc, char *argv[])
 {
   switch (argc)
   {
   case 2:
-    complain (loc, w, "%s", _(argv[1]));
+    complain_indent (loc, w, indent, "%s", _(argv[1]));
     break;
   case 3:
-    complain (loc, w, _(argv[1]), argv[2]);
+    complain_indent (loc, w, indent, _(argv[1]), argv[2]);
     break;
   case 4:
-    complain (loc, w, _(argv[1]), argv[2], argv[3]);
+    complain_indent (loc, w, indent, _(argv[1]), argv[2], argv[3]);
     break;
   case 5:
-    complain (loc, w, _(argv[1]), argv[2], argv[3], argv[4]);
+    complain_indent (loc, w, indent, _(argv[1]), argv[2], argv[3], argv[4]);
     break;
   case 6:
-    complain (loc, w, _(argv[1]), argv[2], argv[3], argv[4], argv[5]);
+    complain_indent (loc, w, indent, _(argv[1]), argv[2], argv[3], argv[4],
+                     argv[5]);
     break;
   default:
     complain (loc, fatal, "too many arguments for complains");

src/complain.h

@@ -62,7 +62,8 @@ void complain (location const *loc, warnings flags, char const *message, ...)
   __attribute__ ((__format__ (__printf__, 3, 4)));
 
 /** Likewise, but with an \a argc/argv interface.  */
-void complain_args (location const *loc, warnings w, int argc, char *arg[]);
+void complain_args (location const *loc, warnings w, unsigned *indent,
+                    int argc, char *arg[]);
 
 /** Make a complaint with location and some indentation.  */
 void complain_indent (location const *loc, warnings flags, unsigned *indent,

src/scan-skel.l

@@ -175,6 +175,8 @@ flag (const char *arg)
     return complaint;
   else if (STREQ (arg, "fatal"))
     return fatal;
+  else if (STREQ (arg, "note"))
+    return silent;
   else
     aver (false);
 }
@@ -190,9 +192,12 @@ at_directive_perform (int argc, char *argv[], char **outnamep, int *out_linenop)
     }
   else if (STREQ (argv[0], "@complain"))
     {
+      static unsigned indent;
       if (argc < 4)
         fail_for_at_directive_too_few_args (argv[0]);
       warnings w = flag (argv[1]);
+      if ((w & silent) != silent)
+        indent = 0;
       location loc;
       location *locp = NULL;
       if (argv[2] && argv[2][0])
@@ -201,8 +206,12 @@ at_directive_perform (int argc, char *argv[], char **outnamep, int *out_linenop)
           boundary_set_from_string (&loc.end, argv[3]);
           locp = &loc;
         }
-      complain_args (locp, w, argc - 3, argv + 3);
+      if (w & silent)
-    }
+        indent += SUB_INDENT;
+      complain_args (locp, w, &indent, argc - 3, argv + 3);
+      if (w & silent)
+        indent -= SUB_INDENT;
+     }
   else if (STREQ (argv[0], "@output"))
     {
       if (argc > 2)

tests/input.at

@@ -1159,9 +1159,9 @@ start: ;
 ]])
 AT_BISON_CHECK([[input.y]], [1], [],
 [[input.y:1.9-21: error: invalid value for %define variable 'api.push-pull': 'neither'
-input.y:1.9-21: error: accepted value: 'pull'
+input.y:1.9-21:     accepted value: 'pull'
-input.y:1.9-21: error: accepted value: 'push'
+input.y:1.9-21:     accepted value: 'push'
-input.y:1.9-21: error: accepted value: 'both'
+input.y:1.9-21:     accepted value: 'both'
 ]])
 
 AT_CLEANUP
@@ -1183,9 +1183,9 @@ start: ;
 AT_BISON_CHECK([[input.y]], [1], [],
 [[input.y:1.9-21: warning: deprecated %define variable name: 'api.push_pull', use 'api.push-pull' [-Wdeprecated]
 input.y:1.9-21: error: invalid value for %define variable 'api.push-pull': 'neither'
-input.y:1.9-21: error: accepted value: 'pull'
+input.y:1.9-21:     accepted value: 'pull'
-input.y:1.9-21: error: accepted value: 'push'
+input.y:1.9-21:     accepted value: 'push'
-input.y:1.9-21: error: accepted value: 'both'
+input.y:1.9-21:     accepted value: 'both'
 ]])
 
 AT_DATA([[input.y]],