[antlr-interest] Tree grammar for expression subrules?
g4 at novadsp.com
g4 at novadsp.com
Fri Mar 4 09:53:59 PST 2011
Is there a pattern to follow for creating tree grammars for subrules?
// parser rule. this works.
expression
: (a=term -> $a) ( ( '|' b=term -> ^(OR $expression $b)
| '|' -> ^(OR $expression EPSILON)
)
)*
;
// tree grammar 1, based on CMinus example in the book.Throws a
MismatchedTreeNodeException complaining about lack of
// 'UP' at SEQUENCE_EXPR
expression
: IF_ACTION
| ID
| ID ATTRIBUTES
| STRINGLITERAL
| EPSILON
| ^(GROUPED_EXPR expression)
| ^(OPTIONAL_EXPR expression)
| ^(SEQUENCE_EXPR expression)
;
Any pointers welcomed. Thx++
Jerry
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