[antlr-interest] Template Rewrite Rule consumes one more Token than expected
antlr at mirality.co.nz
Mon Apr 21 13:29:04 PDT 2008
At 01:51 22/04/2008, Felix Dorner wrote:
>Right, but it does not delete the ";" from the corresponding
>I expect the "a*b" to be replaced by "where's the
>the semicolon should remain in the token stream.
>The template rewrite rule for an "expression" should only
>the tokens that were matched for that expression.
That's not how it works. The parser outputs an AST, presumed to
be a complete representation of the parsed content. The tree
parser takes the AST as input, and based on the nodes present in
the tree either executes some actions or generates some output
based on templates. If there isn't a node for a token, it doesn't
go and magically re-insert it into the output, it assumes you
intentionally left it out of the AST because you don't want it in
the output (eg. maybe you've replaced it by something more
interesting, or maybe it's just structural and is irrelevant in
the AST anyway).
If you want to get the semicolon in the output, then remove the !
from it so that it gets inserted into the AST. The tree parser
can only see what's in the AST.
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