[antlr-interest] Syntactic Predicate with Tree Grammar
Fred
phreed at gmail.com
Thu Feb 14 11:50:05 PST 2008
Given an AST as follows...
<A>
<B>
<C>
<E>
<F>
<D>
<F>
...or expanded into a node list {where '(' means DOWN and ')' means UP}...
A ( B ( C ( E ( F ) ) D ( F ) ) )
...and a tree grammar (fragment)...
expr
: (^(B ^(C .) .))=>
^(B ^(C a1=.) b1=.) -> doX()
| ^(B a2=. b2=.) -> doY()
;
...I get an error like...
A.g: node from after line ..:.. no viable alternative at input 'UP'
...where the line number corresponds to the C node.
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