Hi.

I wrote the following program to show the problem.

It uses very simple plex and pyacc modules that only try to find out if a line of the input contais the word "hallo". The main program does the following:
* open a file
* parse it
* print "----successful parse!----"
* reopen it
* parse it again
...

The first time parsing the file works well.
The second time works almost, but have a look yourself:

LEX: Found HALLO
YACC: Line containing Hallo found.
LEX: Found some text.
YACC: Line with some other text found.
LEX: Found HALLO
YACC: Line containing Hallo found.
---------successful parse!---------------
Reset.
LEX: Found HALLO
YACC: Line containing Hallo found.
LEX: Found some text.
YACC: Line with some other text found.
LEX: Found HALLO
YACC: Line containing Hallo found.
Runtime error 103 at 0x08053A3A
0x08053A3A
0x080480B0
0x00000000

The runtime error is 103 but the return code of the program was 0147 (shown by gdb).

I have tested version 1.0.4 and 1.0.6 of fpc under Linux on i386. Both with the same result.

I can't say if is a fpc problem or a problem of the state machine generated by pyacc.

I have added the following files to this mail:
* Makefile - for easier testing :-)
* yaccerror.pp - the main program
* yaccerror_lex.l - the lex file
* yaccerror_yacc.y - the yacc file
* hallofile.txt - the textfile used above

What I have done so far:
- looked through the documentation/examples of tply41a.
- written a program that opens a textfile and displays all lines several times to see if "Reset" works. It worked.
- some sessions with DDD (frontend for gdb)
- tested fpc 1.0.4 ad 1.0.6

Thank you,

Ralf Paaschen

Compile everything with -gl, then you'll get line numbers next to the reutrn addresses, which should help you pinpoint the problem.

Jonas

I just tried this but the line number I get is the one where yyparse() is called. But thanks to the output on screen and DDD/gdb I know that most of the yyparse procedure gets executed.

But I turned on the pyacc debug code. Then every internal state is printed. And there is a difference towards the end of execution of the both yyparse calls:

YACC: Line containing Hallo found.
state 2, char -1
reduce 2
state 1, char 0
---------successful parse!---------------

YACC: Line containing Hallo found.
state 2, char -1
reduce 2
Runtime error 103 at 0x0805426C

The "state 1, char 0" is never reached in the second case.

But at the moment I don't know how this can help me...

Greetings,
Ralf