+
+
+
+## -------------------------- ##
+## Printers and Destructors. ##
+## -------------------------- ##
+
+AT_SETUP([Printers and 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
+%}
+%verbose
+%union
+{
+ int ival;
+}
+%type <ival> 'x' thing line input
+
+%printer { fprintf (yyout, "%d from %d", $$, @$.first_line); }
+ input line thing 'x'
+
+%destructor
+ {
+ fprintf (stdout, "Freeing ");
+ /* FIXME: Ouch: INTERNAL DETAILS EXPOSED HERE. */
+ /* Cannot use $$ which is the union member, not the union itself. */
+ yysymprint (stdout, yytype, yyvalue, @$);
+ fprintf (stdout, "\n");
+ }
+ input line thing 'x'
+
+%{
+static int yylex (void);
+static void yyerror (const char *msg);
+%}
+
+
+%%
+input:
+ /* Nothing. */
+ {
+ $$ = 0;
+ printf ("input(%d): /* Nothing */';'\n", $$);
+ }
+| line input /* Right recursive to load the stack so that popping at
+ EOF can be exercised. */
+ {
+ $$ = 2;
+ printf ("input(%d): line(%d) input(%d)';'\n", $$, $1, $2);
+ }
+;
+
+line:
+ thing thing thing ';'
+ {
+ $$ = $1;
+ printf ("line(%d): thing(%d) thing(%d) thing(%d) ';'\n", $$, $1, $2, $3);
+ }
+| thing thing ';'
+ {
+ $$ = $1;
+ printf ("line(%d): thing(%d) thing(%d) ';'\n", $$, $1, $2);
+ }
+| thing ';'
+ {
+ $$ = $1;
+ printf ("line(%d): thing(%d) ';'\n", $$, $1);
+ }
+| error ';'
+ {
+ $$ = -1;
+ printf ("line(%d): error ';'\n", $$);
+ }
+;
+
+thing:
+ 'x'
+ {
+ $$ = $1;
+ printf ("thing(%d): 'x'(%d)\n", $$, $1);
+ }
+;
+%%
+static int
+yylex (void)
+{
+ static const unsigned int input[] =
+ {
+ /* Exericise the discarding of stack top and input until `error'
+ can be reduced. */
+ 'x', 'x', 'x', 'x', 'x', 'x', ';',
+
+ /* Load the stack and provoke an error that cannot be caught by
+ the grammar, to check that the stack is cleared. */
+ 'x', 'x', ';',
+ 'x', ';',
+ 'y'
+ };
+ static unsigned int counter = 0;
+
+ if (counter < (sizeof(input) / sizeof (input[0])))
+ {
+ yylval.ival = counter;
+ /* As in BASIC, line numbers go from 10 to 10. */
+ yylloc.first_line = 10 * counter;
+ printf ("sending: '%c' (value = %d, line %d)\n",
+ input[counter], yylval.ival, yylloc.first_line);
+ return (int) input[counter++];
+ }
+ else
+ {
+ printf ("sending: EOF\n");
+ return EOF;
+ }
+}
+
+static void
+yyerror (const char *msg)
+{
+ fprintf (stdout, "%d: %s\n", yylloc.first_line, msg);
+}
+
+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 --location -d -v -o input.c])
+AT_COMPILE([input])
+AT_PARSER_CHECK([./input], 1,
+[[sending: 'x' (value = 0, line 0)
+thing(0): 'x'(0)
+sending: 'x' (value = 1, line 10)
+thing(1): 'x'(1)
+sending: 'x' (value = 2, line 20)
+thing(2): 'x'(2)
+sending: 'x' (value = 3, line 30)
+30: parse error, unexpected 'x', expecting ';'
+Freeing nterm thing (2 from 20)
+Freeing nterm thing (1 from 10)
+Freeing nterm thing (0 from 0)
+Freeing token 'x' (3 from 30)
+sending: 'x' (value = 4, line 40)
+Freeing token 'x' (4 from 40)
+sending: 'x' (value = 5, line 50)
+Freeing token 'x' (5 from 50)
+sending: ';' (value = 6, line 60)
+line(-1): error ';'
+sending: 'x' (value = 7, line 70)
+thing(7): 'x'(7)
+sending: 'x' (value = 8, line 80)
+thing(8): 'x'(8)
+sending: ';' (value = 9, line 90)
+line(7): thing(7) thing(8) ';'
+sending: 'x' (value = 10, line 100)
+thing(10): 'x'(10)
+sending: ';' (value = 11, line 110)
+line(10): thing(10) ';'
+sending: 'y' (value = 12, line 120)
+120: parse error, unexpected $undefined, expecting $end or 'x'
+sending: EOF
+Freeing nterm line (10 from 100)
+Freeing nterm line (7 from 70)
+Freeing nterm line (-1 from 50)
+Parsing FAILED.
+]])
+
+AT_CLEANUP