[antlr-interest] Generating AST trees
Richard Knight <r.knight at zoodigitalgroup.com>
r.knight at zoodigitalgroup.com
Sun Feb 2 14:11:34 PST 2003
I'm a bit of a newbie at all this, so apologies if this doesn't make
a lot of sense...
I'm trying to figure out how to use the AST generation stuff to
generate a parse tree in the way I want (or at least think I
want!). Say I have a grammar that looks something like:
expression: left operation right ;
operation: OP1 | OP2 | OP3;
left: ...more grammar...
right: ...more grammar...
So in the rule for expression there are no explicit tokens that have
come out of the lexer. I'd like to generate a tree like:
/ | \
/ | \
/ | \
left operation right
only it seems there's no way to generate nodes in the tree that
correspond to rules, rather than tokens, unless I'm missing
something (quite likely !).
I could achieve it by manually by inserting code fragments into the
grammar, but it seems like a lot of effort when the automagic AST
generation seems like it might be able to do almost what I want...
Any ideas how I might get around this ?
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