d: add internationalisation support

The D parser implements this feature similarly to the C parser,
by using Gettext. Functions gettext() and dgettext() are
imported using extern(C). The internationalisation uses yysymbol_name
to report the name of the SymbolKinds.

* data/skeletons/d.m4 (SymbolKind.toString.yytranslatable,
SymbolKind.toString.yysymbol_name: New), data/skeletons/lalr1.d: Here.
* doc/bison.texi: Document it.
* tests/calc.at: Test it.

data/skeletons/d.m4

@@ -192,7 +192,12 @@ b4_symbol_foreach([b4_token_enum])dnl
 }
 ])
 
-
+# b4_symbol_translate(STRING)
+# ---------------------------
+# Used by "bison" in the array of symbol names to mark those that
+# require translation.
+m4_define([b4_symbol_translate],
+[[_($1)]])
 
 ## -------------- ##
 ## Symbol kinds.  ##
@@ -252,8 +257,17 @@ m4_define([b4_declare_symbol_enum],
     final void toString(W)(W sink) const
     if (isOutputRange!(W, char))
     {
-      string yystr = yytname_[yycode_];
+      immutable string[] yy_sname = @{
+  ]b4_symbol_names[
+      @};]b4_has_translations_if([[
+      /* YYTRANSLATABLE[SYMBOL-NUM] -- Whether YY_SNAME[SYMBOL-NUM] is
+        internationalizable.  */
+      immutable ]b4_int_type_for([b4_translatable])[[] yytranslatable = @{
+  ]b4_translatable[
+      @};
 
+        put(sink, yy_sname[yycode_]);]], [[
+      string yystr = yytname_[yycode_];
       if (yystr[0] == '"')
         {
         strip_quotes:
@@ -280,9 +294,7 @@ m4_define([b4_declare_symbol_enum],
       {
         put(sink, "end of input");
         return;
-      }
+      }]])[
-
-      put(sink, yystr);
     }
   }
 ]])

data/skeletons/lalr1.d

@@ -40,6 +40,29 @@ version(D_Version2) {
 ]b4_user_post_prologue[
 ]b4_percent_code_get([[imports]])[
 import std.format;
+import std.conv;
+
+/**
+ * Handle error message internationalisation.
+ */
+static if (!is(typeof(YY_))) {
+  version(YYENABLE_NLS)
+  {
+    version(ENABLE_NLS)
+    {
+      extern(C) char* dgettext(const char*, const char*);
+      string YY_(const char* s)
+      {
+        return to!string(dgettext("bison-runtime", s));
+      }
+    }
+  }
+  static if (!is(typeof(YY_)))
+  {
+    pragma(inline, true)
+    string YY_(string msg) { return msg; }
+  }
+}
 
 /**
  * A Bison parser, automatically generated from <tt>]m4_bpatsubst(b4_file_name, [^"\(.*\)"$], [\1])[</tt>.
@@ -680,20 +703,38 @@ m4_popdef([b4_at_dollar])])dnl
       immutable int argmax = 5;
       SymbolKind[] yyarg = new SymbolKind[argmax];
       int yycount = yysyntaxErrorArguments(yyctx, yyarg, argmax);
-      string res = "syntax error, unexpected ";
+      string res, yyformat;
-      res ~= format!"%s"(yyarg[0]);
+      import std.string;
-      if (yycount < argmax + 1)
+      switch (yycount)
       {
-        for (int yyi = 1; yyi < yycount; yyi++)
+        case  1:
-        {
+          yyformat = YY_("syntax error, unexpected %s");
-          res ~= yyi == 1 ? ", expecting " : " or ";
+          res = format(yyformat, yyarg[0]);
-          res ~= format!"%s"(SymbolKind(yyarg[yyi]));
+         break;
-        }
+        case  2:
+          yyformat = YY_("syntax error, unexpected %s, expecting %s");
+          res = format(yyformat, yyarg[0], yyarg[1]);
+          break;
+        case  3:
+          yyformat = YY_("syntax error, unexpected %s, expecting %s or %s");
+          res = format(yyformat, yyarg[0], yyarg[1], yyarg[2]);
+          break;
+        case  4:
+          yyformat = YY_("syntax error, unexpected %s, expecting %s or %s or %s");
+          res = format(yyformat, yyarg[0], yyarg[1], yyarg[2], yyarg[3]);
+          break;
+        case  5:
+          yyformat = YY_("syntax error, unexpected %s, expecting %s or %s or %s or %s");
+          res = format(yyformat, yyarg[0], yyarg[1], yyarg[2], yyarg[3], yyarg[4]);
+          break;
+        default:
+          res = YY_("syntax error");
+          break;
       }
       yyerror(]b4_locations_if([yyctx.getLocation(), ])[res);
     }]],
 [[simple]], [[
-    yyerror(]b4_locations_if([yyctx.getLocation(), ])["syntax error");]])[
+    yyerror(]b4_locations_if([yyctx.getLocation(), ])[YY_("syntax error"));]])[
   }
 
 ]b4_parse_error_bmatch(

doc/bison.texi

@@ -13953,6 +13953,66 @@ or nonzero, full tracing.
 Identify the Bison version and skeleton used to generate this parser.
 @end deftypecv
 
+The internationalization in D is very simmilar to the one in C. The D
+parser uses @code{dgettext} for translating Bison messages.
+
+To enable internationalisation, compile using
+@code{-version ENABLE_NLS -version YYENABLE_NLS} and import
+@code{bindtextdomain} and @code{textdomain} from C:
+
+@example
+extern(C) char* bindtextdomain(const char* domainname, const char* dirname);
+extern(C) char* textdomain(const char* domainname);
+@end example
+
+The main function should load the translation catalogues, similarly to the
+@file{c/bistromathic} example:
+
+@example
+int main()
+@{
+  import core.stdc.locale;
+
+  // Set up internationalization.
+  setlocale(LC_ALL, "");
+  // Use Bison's standard translation catalogue for error messages
+  // (the generated messages).
+  bindtextdomain("bison-runtime", BISON_LOCALEDIR);
+  // For the translation catalogue of your own project, use the
+  // name of your project.
+  bindtextdomain("bison", LOCALEDIR);
+  textdomain("bison");
+
+  // usual main content
+  ...
+@}
+@end example
+
+For user messages translations, the user must implement the
+@code{string} _(@code{const char*} @var{msg}) function and it is recommended
+to use @code{gettext}:
+
+@example
+%code imports @{
+  static if (!is(typeof(_)))
+  @{
+    version(ENABLE_NLS)
+    @{
+      extern(C) char* gettext(const char*);
+      string _(const char* s)
+      @{
+        return to!string(gettext(s));
+      @}
+    @}
+  @}
+  static if (!is(typeof(_)))
+  @{
+    pragma(inline, true)
+    string _(string msg) @{ return msg; @}
+  @}
+@}
+@end example
+
 @node D Parser Context Interface
 @subsection D Parser Context Interface
 The parser context provides information to build error reports when you

tests/calc.at

@@ -654,6 +654,23 @@ m4_define([_AT_DATA_CALC_Y(d)],
 };
 %printer { fprintf (yyo, "%d", $$); } <ival>;
 
+%code {
+]AT_TOKEN_TRANSLATE_IF([[
+  static string _(string s)
+  {
+    switch (s)
+    {
+      case "end of input":
+        return "end of file";
+      case "number":
+        return "nombre";
+      default:
+        return s;
+    }
+  }
+]])[
+}
+
 /* Bison Declarations */
 %token EOF 0 ]AT_TOKEN_TRANSLATE_IF([_("end of file")], ["end of input"])[
 %token <ival> NUM   "number"
@@ -665,7 +682,7 @@ m4_define([_AT_DATA_CALC_Y(d)],
        STAR   "*"
        SLASH  "/"
        POW    "^"
-       EOL    "\n"
+       EOL    "'\\n'"
        LPAR   "("
        RPAR   ")"
        NOT    "!"