[antlr-interest] retrieving the length of a production match

[Adrian Herscu]

Hi Randall, and thanks for your fast reply.
Please see my comments inline.
Adrian.

Randall R Schulz wrote:
> On Tuesday 21 August 2007 12:32, Adrian Herscu wrote:
>> Hi all,
>>
>> I want to embed my parser in an IDE. One of the required features is
>> to provide error markers. The markers framework API requires the
>> length of the error besides of the line and column.
> 
> Technically speaking, parse errors don't have a length. There is a point 
> (a single token) at which the parser can detect ungrammatical input. 
> After that, it's all over.

I can deal with parsing errors by extracting the token from the 
exception. The problem is with things beyond the syntax, like type checking.

I will rephrase the question. On a syntactically correct input, is it 
possible to retrieve the textual length of each production match and 
store it in the AST during parsing?

> 
> Of course, people often try to go beyond that elementary kind of yes / 
> no parsing and add some kind recovery. My favorite "universal" 
> (non-parser-tool-dependent) technique is to write production for 
> explicitly non-grammatical (but usually common) errors so that you can 
> report them and continue parsing.
> 
> Other more sophisticated, parser-generator-specific techniques are 
> possible, but I'm not up on them. The topic is covered extensively in 
> TDAR.
> 

What is "TDAR"?