Re: [GNU-COBOL] GNU-COBOL list reborn

[Tim Josling <tej@melbpc.org.au>]

Michael,
I am playing around with BTYACC and I intend to start heavy duty
trial parsing of various test cases this weekend. Could we work
together on some test cases to exercise the parser generators? 

Here is an example:

move a to b (2 * c + d) (1:2).
move a to b (2:3).
.............^

At the point of the "^" there is an ambiguity whether you are
looking at a reference modification or an array reference.

As far as I can tell, no finite amount of lookahead can get past
this problem, just based on syntactic processing (of course there
is the standard 'typedef' hack that can help with this (see the
Bison manual for details) - but this gets ugly fast.	

Any other hard cases would be great as well.

On the runtime side, I think it would be good for people to start
work on that. Ther is a lot of work there.

I suggest 

1) Suggest an interface to the runtime to the team (for each of
the many runtime things - sort, file handling, merge, report
writer).

2) Assuming people on the parser side agree, do it. 

My approach at the moment is to get something that works,
focusing on the nucleus level 1 and on up first. Worry about
performance later. The simplest thing that can possibly work.

Tim Josling

Michael McKernan wrote:
> ...
> Looks like it might be time for me to climb down from the soapbox and
> do some work around here, so unless Tim is determined to do it, I'll
> (shudder) commit to doing the parser.
> 
> Mike


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