* data/m4sugar/m4sugar.m4 (m4_map): Recognize when the list of

arguments is really empty, not only equal to `[]'.
* src/symtab.h, src/symtab.c (symbol_t): `destructor' is a new
member.
(symbol_destructor_set): New.
* src/output.c (symbol_destructors_output): New.
* src/reader.h (brace_code_t, current_braced_code): New.
* src/scan-gram.l (BRACED_CODE): Use it to branch on...
(handle_dollar): Rename as...
(handle_action_dollar): this.
(handle_destructor_dollar): New.
* src/parse-gram.y (PERCENT_DESTRUCTOR): New.
(grammar_declaration): Use it.
* data/bison.simple (yystos): Is always defined.
(yydestructor): New.
* tests/actions.at (Destructors): New.
* tests/calc.at (_AT_CHECK_CALC_ERROR): Don't rely on egrep.

tests/actions.at

@@ -88,8 +88,6 @@ AT_CLEANUP
 
 AT_SETUP([Exotic Dollars])
 
-# Make sure complex $n work.
-
 AT_DATA([[input.y]],
 [[%{
 # include <stdio.h>
@@ -152,3 +150,133 @@ AT_CHECK([./input], 0,
 ]])
 
 AT_CLEANUP
+
+
+
+## ------------- ##
+## Destructors.  ##
+## ------------- ##
+
+AT_SETUP([Destructors])
+
+# Make sure complex $n work.
+
+AT_DATA([[input.y]],
+[[%{
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#define YYERROR_VERBOSE 1
+#define YYDEBUG 1
+/* #define YYPRINT yyprint */
+
+static int yylex (void);
+static void yyerror (const char *msg);
+static void yyprint (FILE *out, int toknum, int tokval);
+%}
+
+%union
+{
+  int ival;
+}
+%type <ival> thing 'x'
+%destructor { printf ("Freeing thing %d\n", $$); } thing
+%destructor { printf ("Freeing 'x' %d\n", $$); } 'x'
+
+%%
+input:
+  /* Nothing. */
+| input line
+;
+
+line:
+  thing thing thing ';'
+    { printf ("input: thing(%d) thing(%d) thing(%d) ';'\n", $1, $2, $3); }
+| thing thing ';'
+    { printf ("input: thing(%d) thing(%d) ';'\n", $1, $2); }
+| thing ';'
+    { printf ("input: thing(%d) ';'\n", $1); }
+| error ';'
+    { printf ("input: error ';'\n"); }
+;
+
+thing:
+  'x'  { printf ("thing: 'x' (%d)\n", $1); $$ = $1; }
+;
+%%
+static int
+yylex (void)
+{
+  static const int input[] =
+    {
+      'x', 'x', 'x', 'x', 'x', 'x', ';',
+      'x', 'x', ';',
+      'x', ';',
+      'x', 'y', ';'
+    };
+  static int counter = 0;
+
+  if (counter < (sizeof(input) / sizeof (input[0])))
+    {
+       yylval.ival = counter;
+       return input[counter++];
+    }
+  else
+    return EOF;
+}
+
+static void
+yyerror (const char *msg)
+{
+  fprintf (stdout, "%s\n", msg);
+}
+
+static void
+yyprint (FILE *out, int toknum, int tokval)
+{
+  if (0 < toknum && toknum < 256)
+    fprintf (out, " = %d", tokval);
+}
+
+int
+main (void)
+{
+  yydebug = !!getenv ("YYDEBUG");
+  if (yyparse ())
+    {
+      fprintf (stdout, "Parsing FAILED.\n");
+      exit (1);
+    }
+  fprintf (stdout, "Successful parse.\n");
+  return 0;
+}
+]])
+
+AT_CHECK([bison input.y -d -v -o input.c])
+AT_CHECK([$CC $CFLAGS $CPPFLAGS input.c -o input], 0, [], [ignore])
+AT_CHECK([./input], 0,
+[[thing: 'x' (0)
+thing: 'x' (1)
+thing: 'x' (2)
+parse error, unexpected 'x', expecting ';'
+Freeing thing 2
+Freeing thing 1
+Freeing thing 0
+Freeing 'x' 3
+Freeing 'x' 4
+Freeing 'x' 5
+input: error ';'
+thing: 'x' (7)
+thing: 'x' (8)
+input: thing(7) thing(8) ';'
+thing: 'x' (10)
+input: thing(10) ';'
+thing: 'x' (12)
+parse error, unexpected $undefined., expecting 'x' or ';'
+Freeing thing 12
+input: error ';'
+Successful parse.
+]])
+
+AT_CLEANUP

tests/calc.at

@@ -354,7 +354,16 @@ m4_bmatch([$1], [--debug],
 # Normalize the observed and expected error messages, depending upon the
 # options.
 # 1. Remove the traces from observed.
-egrep -v '^((Start|Enter|Read|Reduc|Shift)ing|state|Error:|Next|Discarding) ' stderr >at-stderr
+sed '/^Starting/d
+/^Entering/d
+/^Reading/d
+/^Reducing/d
+/^Shifting/d
+/^state/d
+/^Error:/d
+/^Next/d
+/^Discarding/d
+/^yydestructor:/d' stderr >at-stderr
 mv at-stderr stderr
 # 2. Create the reference error message.
 AT_DATA([[expout]],
@@ -406,18 +415,18 @@ _AT_CHECK_CALC([$1],
 (2^2)^3 = 64], [486])
 
 # Some parse errors.
-_AT_CHECK_CALC_ERROR([$1], [0 0], [11],
+_AT_CHECK_CALC_ERROR([$1], [0 0], [12],
                      [1.3-1.4: parse error, unexpected "number"])
-_AT_CHECK_CALC_ERROR([$1], [1//2], [15],
+_AT_CHECK_CALC_ERROR([$1], [1//2], [17],
                      [1.3-1.4: parse error, unexpected '/', expecting "number" or '-' or '('])
 _AT_CHECK_CALC_ERROR([$1], [error], [4],
                      [1.1-1.2: parse error, unexpected $undefined., expecting "number" or '-' or '\n' or '('])
-_AT_CHECK_CALC_ERROR([$1], [1 = 2 = 3], [22],
+_AT_CHECK_CALC_ERROR([$1], [1 = 2 = 3], [25],
                      [1.7-1.8: parse error, unexpected '='])
 _AT_CHECK_CALC_ERROR([$1],
                      [
 +1],
-                     [14],
+                     [15],
                      [2.1-2.2: parse error, unexpected '+'])
 # Exercise error messages with EOF: work on an empty file.
 _AT_CHECK_CALC_ERROR([$1],
@@ -430,7 +439,7 @@ _AT_CHECK_CALC_ERROR([$1],
 # associated to `error'.
 _AT_CHECK_CALC_ERROR([$1],
                      [(1 ++ 2) + (0 0) = 1],
-                     [82],
+                     [91],
 [1.5-1.6: parse error, unexpected '+', expecting "number" or '-' or '('
 1.15-1.16: parse error, unexpected "number"
 calc: error: 0 != 1])