Stack Overflow when Pyparsing Ada 2005 Scoped Identifiers using Reference Manual Grammar

[per.nordlow@gmail.com]

I'm currently implementing an Ada 2005 parser using Pyparsing and the reference manual grammar rules. We need this in order to analyze and transform parts of our aging Ada-codebase to C/C++.

Most things work.

However, one little annoying problem remains:

The grammar rule name when parsing scoped identifiers (rule selected_component) such as the expression "Global_Types.Integer2" fails because it is part of a left-associative grammar rule cycle.

Pyparsing infinite recursion and Python spits out maximum recursion depth exceeded.

I believe the problem is caused either by the fact that

•the associativity of the grammar rule selected_component is right-to-left. I've search the reference manual of Pyparsing but haven't found anything relevant. Should we treat dot (.) as an operator with right-to-left associativity or can we solve it throught extensions and restructurings of the grammar rules?

•or by the fact that there is no check in Pyparsing infinite recursions. I believe this wouldn't be too hard to implement. Use a map from currently active rules (functions) to source position/offset (getTokensEndLoc()) and always fail a rule if the current source input position/offset equals the position related to the rule just entered.

The problem also seems closely related to

"Need help in parsing part of python grammar": http://pyparsing.wikispaces.com/message/view/home/51617848

which unfortunately doesn't have answers yet.

Also see this thread

http://stackoverflow.com/questions/15438015/stack-overflow-when-pyparsing-ada-2005-scoped-identifiers-using-reference-manual?noredirect=1#comment22014663_15438015

Thanks in advance,
Per Nordlöw