[antlr-interest] Syntax Errors in Tree grammars because of trees multiplicities

Nieves.Salor.Moral at esa.int Nieves.Salor.Moral at esa.int
Fri Aug 27 01:57:50 PDT 2010


Hello everyone!!

I am currently writing the tree grammar from my parse one, and I have 
discovered that I get errors if I use structures like these:

a: ^(A1 b+)
;

b: ^(B1 b  ^(ACTION c)*)
;

c: whatever


But, it works if I change the previous tree grammar like this:

a: ^(A1 b+)
;

b: ^(B1 b  b_sub*)
;

b_sub: ^(ACTION c)
;

c: whatever


The same happens each time that I use a modifier of multiplicity (?,*,+) 
for a whole parse tree. Why is it not allowed? How can I solve this?

Thanks in advance

Nieves


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