Files
bison/examples/c/reccalc
Akim Demaille 6135fdc152 examples: beware of portability issues with sh's trap
On AIX 7.2, when invoking "exit 77", we actually exit with 127.  The
"cleanup" function, called via trap, received an incorrect exit
status, something described in Autoconf's doc.
Reported by Bruno Haible.
https://lists.gnu.org/archive/html/bug-bison/2020-05/msg00029.html
https://lists.gnu.org/archive/html/bug-bison/2020-05/msg00047.html

* examples/test (skip): New.
* examples/c/bistromathic/bistromathic.test,
* examples/c/reccalc/reccalc.test: Use it, to ensure $? is set to 77
when the trap is called.
2020-05-04 06:48:00 +02:00
..
2019-10-23 23:09:56 +02:00
2020-01-26 14:02:08 +01:00

reccalc - recursive calculator with Flex and Bison

In this example the generated parser is pure and reentrant: it can be used concurrently in different threads, or recursively. As a proof of this reentrancy, expressions in parenthesis are tokenized as strings, and then recursively parsed from the parser:

exp: STR
  {
    result r = parse_string ($1);
    free ($1);
    if (r.nerrs)
      {
        res->nerrs += r.nerrs;
        YYERROR;
      }
    else
      $$ = r.value;
  }