[GNU-COBOL] COBOL Grammars and Parsers

[Michael McKernan <mck@tivoli.mv.com>]

Greetings,

Being a newbie on this list, I'll ask your indulgence while I bring
up a matter which seems to be considered long since settled.  I'm
referring to the rejection of pccts as "inadequate for the needs of
the project".  As I have been, here-to-fore at least, a
non-contributor, I certainly have no right to demand an explanation,
but I do find the decision surprising and I wonder if anyone would
like to enlighten me about the shortcomings of pccts.

A few years ago, I used pccts to build a preprocessor for PL/I which
implemented, insofar as I was able to determine it from the user's
manual, the original IBM dialect.  This is a very crufty language,
and although I needed to hack the pccts code a bit (not in the
"sophisticated parts"), I was impressed with its ability to deal with
this ancient hand coded recursive descent kludge.

I have also been an implementor on three or six (depending on how one
counts retargetting) commercial COBOL compilers, all of which used
home-grown table driven recursive descent parsers.  My experience
with the preprocessor convinced me that pccts would be a good choice
should I ever have the occasion to parse COBOL again. This is partly
because of the possibility of infinite lookahead, but primarily
because of semantic predicates, which I think would be extremely
helpful in getting well formed trees directly from the parser.

I hope this hasn't been too irksome for a first post, but I wanted to
get this little issue off the table, early on.  Thanks for listening.

Mike






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