[antlr-interest] Undocumented error message
William B. Clodius
wclodius at los-alamos.net
Thu Oct 8 21:10:21 PDT 2009
As a hobby I have started using ANTLR V3 to design a language. So far
I am at the pure syntax stage, building up a grammar that is intended
to be pure LL(*), in the expectation that it will allow me to provide
more specific and clearer error messages than is typically provided by
an LR(n) parser. I have so far not deliberately added actions,
syntactic predicates, etc. Today I have been getting error messages in
the console of ANTLR-Works 1.3 for which I have found no documentation
on the net. Yesterday I downloaded the most recent upgrade so I
suspect the message was added in the recent upgrade. I also have a
question about the general syntax of the messages. The message is of
the form
[20:55:24] error(130): ...:163:15: rule comparison has no defined
parameters
where comparison is my name for the syntactic rule for relational
expressions, and ... represents the name of my grammar file. It turned
out that I had misremembered ANTLR's EBNF syntax and had used square
brackets as delimiters. However I did not use them in the comparison
rule, but rather in the immediately following rule. Further the 163
was not the line number of the start of the comparison rule, or the
following rule, but the line with the colon of the following rule.
This leads to the following questions:
First, what kind of parameters are expected for a rule in ANTLR and
how do I define them?
Second the error messages have a regular syntax for which I have seen
no definition. What is the meaning of the numbers in [20:55:24]? I
had thought that the number where the 163 appears was the line number
of the start of the error, is it? What is the meaning of the number
15? Is there someplace error(130) is documented?
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