Re: Interactive parsing with Bison

[Satya]

> to be able to display positions within each line as well, I think it
> is just the question of putting the right information in the debugger
> file format. In the past, perhaps debugger files would have been
> viewed as becoming to large, but computer space is nowadays is ample:
> It seems me one should ideally not have to change the source code, in
> order to do debugging.

Yes, we want to put a lot of information in the debug file. gdb must
be modified to understand Bison debug files (and possibly flex debug
files ?!);  The only change in Bison source will be the task of
dumping information in .debug files when requested.

regarding the problem of multiple arrows: I think there is more to
it... In addition to displaying the position of dot in various rules,
we have to display the position of the next lexeme in the test-input
file (along with an arrow pointing to the line); that makes it four
arrows in 2 windows. One window shows the grammar, the other one shows
the test-input being parsed. Perhaps we can highlight the (un)parsed
input in a different color?

breakpoints: the user must be able to set a breakpoint at a particular
token in the test-input; This makes it a little complicated. The input
file might have to be pre-scanned by the lexer and broken down into
tokens first, so that a token forms one unit (just as a source line
forms one unit in gdb);

So it finally boils down to 'controlled execution' (of yylex and
yyparse functions). Isn't that what gdb does best?

Satya.