[antlr-interest] custom TokenLabelType and EOF/Error tokens
Bob Frankel
bios.bob.frankel at gmail.com
Tue Nov 10 08:35:05 PST 2009
following idioms i've seen posted elsewhere, i've created a MyToken
class that inherits from CommonToken; my Lexer then overrides Token
Lexer.emit(), at which time i create instances of MyToken....
things work fine, until the parser encounters a syntactic error....
from what i can tell, the parser inserts an "error" token of type
CommonToken; this then leads to a class cast exception in the
surrounding parser rule when attempting to assign a CommonToken value
through a generated (MyToken) cast....
i've also noticed a similar problem when my grammar explictly includes
the special EOF token; again, the token created here is of type
CommonToken, which leads to a class cast exception when later assigned
through a (MyToken) cast inside the generated parser class....
is there some other method i should be overriding beyond Token
Lexer.emit()???
thanks....
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