[antlr-interest] Parse tree error messages.
Ric Klaren
klaren at cs.utwente.nl
Tue Apr 1 03:25:47 PST 2003
Hi,
On Fri, Mar 28, 2003 at 05:41:24AM -0700, Trey Spiva wrote:
> When parsing a file the recognizers report pretty good error messages.
> However, when using parse trees the error messages are very cryptic. Is
> here a way to have the tree parser at least report the token AST type
> that it is expecting and the AST type that if found.
>
> The error message that the tree parser is reporting is:
>
> <AST> : unexpected AST node: <ASTNULL>
During development with treewalkers I usually have in each rule a exception
handler that prints out the offending tree. Something like this:
rule:
( sumthin ) *
sumthin_else
;
exception
catch [antlr::RecognitionException &ex]
{
print_tree<RefMyAST,MyTreeParser> pr(*this);
pr.pr_tree(#rule_in);
}
You can get the print_tree thing here:
http://wwwhome.cs.utwente.nl/~klaren/print_tree.h
Cheers,
Ric
--
-----+++++*****************************************************+++++++++-------
---- Ric Klaren ----- j.klaren at utwente.nl ----- +31 53 4893722 ----
-----+++++*****************************************************+++++++++-------
Chaos always defeats order because it is better organized.
--- Terry Pratchet
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