Is it better to have the fragment rule match the token string, or have a rule
that matches the token string and just use the fragment as the token type? By
better I mean in terms of code size and performance.
For example, say I have fragments FOO and BAR that match 'foo' and 'bar'
(regardless of case), and then I use these in a rule FOO_OR_BAR.
fragment A : 'a' | 'A';
fragment B : 'b' | 'B';
... you get the picture ...
fragment Z : 'z' | 'Z';
fragment FOO : F O O;
fragment BAR : B A R;
FOO_OR_BAR
: FOO { $type = FOO }
| BAR { $type = BAR }
;
or this?
fragment A : 'a' | 'A';
fragment B : 'b' | 'B';
... you get the picture ...
fragment Z : 'z' | 'Z';
fragment FOO : ;
fragment BAR : ;
FOO_OR_BAR
: F O O { $type = FOO }
| B A R { $type = BAR }
;
It is necessary for me to to this 'fragmented' approach. Due to conflicts in
the grammar, FOO and BAR cannot themselves be tokens. Well, I guess I could
resolve the conflicts with syntactic predicates, but I have a large number of
these and wound up with a 'code segment too large' problem.
I'm thinking the first way is better.
--
David Grieve
603-312-1013
[email protected]
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