[antlr-interest] Reusing Lexer/Parser instances

defordusa defordusa at yahoo.com
Fri Jul 11 08:04:47 PDT 2003

My application needs to perform MANY small translations (on the order 
of millions). In order to improve performance I would like to be able 
to reuse instance of the lexer and parser.

I originally posted a question about using the PipedWriter and 
PipedReader classes found in Java 1.3 and above, as I figured this 
way I could write something in the PipedWriter, call the appropriate 
parser rule and get the results. However, I have been unable to get 
this to work as I appear to need to somehow get the lexer to stop 
trying to read on the PipedReader and thus the lexer blocks on a read.

I have been able to reuse the lexer and parser instances calling 
setInputState and setTokenBuffer on the lexer and parser 
respectively. However, I still have the overhead of millions of 
instances being created, dramatically reducing performance.

Is there a better way of doing this?

Here is a snippet of my code:

while( in.ready() )
  lexer.setInputState(new LexerSharedInputState(new StringReader
  parser.setTokenBuffer( new TokenBuffer(lexer) );


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