[antlr-interest] Re: Problems while reusing Lexer/Parser/TreeParser instances

[Terence Parr]

Seems like there will be a file closing/rewinding issue now that you 
mention it ;)  Somehow the actual file must be reset not just the 
internal state.

Ter


On Saturday, September 27, 2003, at 09:11 AM, micheal_jor wrote:

> Would someone please post working code for reusing
> Lexer/Parser/TreeParser instances please?. It can be in any of C++,
> Java and C#.
>
> Cheers
>
> Micheal
>
>> Hi,
>>
>> I'm tinkering with the code below[1*] to support reuse of
>> Lexer/Parser/Treeparser instances with ANTLR/C#:
>>
>> Issues:
>> 1. I haven't tried this in a basic Lexer->Parser situation ;-)
>>
>> 2. Given a situation (a.k.a. pipeline) where Lexer1 and Lexer2 are
>> multiplexed using a TokenStreamSelector that then feeds a Parser, only
>> the first use of an instance of the pipeline is error-free. When
>> parsing the same file repeatedly, the pipeline reports unexpected
>> token errors on pass two and dies catastrophically on pass 3.
>>
>> Any ideas?
>>
>> I reset the state in (2) above as follows:
>> 1. lexer1.resetState(<new-buffer-to-use>)
>> 2. lexer2.resetText()
>> 3. parser.resetState()
>>
>> The TokenStreamSelector doesn't seem to need any tweaking.
>>
>> ***
>> Does (and how) the use of exotic Token classes like HiddenStreamToken
>> (sp?) affect reuse of L/P/T instances?
>>
>> Cheers,
>>
>> Micheal
>>
>> ------------------
>>
>> [1*] Code excerpts below:
>>
>>
>> -----------------------------------------------------------
>> CharScanner.cs
>> -----------------------------------------------------------
>> 520a523,529
>>> 		public virtual void resetState(InputBuffer ib)
>>> 		{
>>> 			text.Length = 0;
>>> 			traceDepth = 0;
>>> 			inputState.resetInput(ib);
>>> 		}
>>>
>>
>> -----------------------------------------------------------
>> Parser.cs
>> -----------------------------------------------------------
>> 283a284,289
>>> 		public virtual void resetState()
>>> 		{
>>> 			traceDepth = 0;
>>> 			inputState.reset();
>>> 		}
>>>
>
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