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Re: lexer speed, was Bison

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> [Compilers spend a lot of time in the lexer, because that's the only
> phase that has to look at the input one character at a time. -John]

When the source code resides in a memory buffer, the time for reading
e.g. the characters of an identifier (in the lexer) is neglectable vs.
the time spent in lookup and entering the identifier into a symbol table
(in the parser).

Even if a lexer reads single characters from a file, most OSs maintain
their own file buffer, so that little overhead is added over the
program-buffered solution.

I really would like to see some current benchmarks about the behaviour
of current compilers and systems.

DoDi
[The benchmarks I did were a while ago, but they showed a large
fraction of time in the lexer.  I wouldn't disagree that building the
symbol table is slow, but figure out some estimate of the ratio of
the number of characters in a source file to the number of tokens,
and that is a rough estimate of how much slower the lexer will be
than the parser. I agree that some current analyses would be useful.
-John]

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Bison determinis​tic LALR(1) parser for Java/C++ (kind of complex langauge) without 'lexar hack' support hsad005@gmail.com - 2012-08-17 11:22 -0700
  Re: Bison determinis​tic LALR(1) parser for Java/C++ (kind of complex langauge) without 'lexar hack' support Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2012-08-18 10:13 +0100
    Re: lexer speed, was Bison Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2012-08-20 01:01 +0100
      Re: lexer speed, was Bison Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2012-08-20 16:14 +0100
      Re: lexer speed, was Bison BGB <cr88192@hotmail.com> - 2012-08-20 14:14 -0500
        Re: lexer speed, was Bison Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2012-08-21 07:40 +0100
      Re: lexer speed, was Bison "BartC" <bc@freeuk.com> - 2012-08-21 17:39 +0100
    Re: Bison determinis​tic LALR(1) parser for Java/C++ (kind of complex langauge) without 'lexar hack' support anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-20 13:35 +0000
      Re: Bison determinis​tic LALR(1) parser for Java/C++ (kind of complex langauge) without 'lexar hack' support BGB <cr88192@hotmail.com> - 2012-08-21 14:45 -0500
        Re: Bison determinis​tic LALR(1) parser for Java/C++ (kind of complex langauge) without 'lexar hack' support "BartC" <bc@freeuk.com> - 2012-08-22 14:04 +0100
          Re: Bison determinis​tic LALR(1) parser for Java/C++ (kind of complex langauge) without 'lexar hack' support BGB <cr88192@hotmail.com> - 2012-08-26 19:37 -0500
            Bison deterministic LALR parser for Java/C++ "BartC" <bc@freeuk.com> - 2012-08-29 22:03 +0100
              speeding up C recompilation, was Re: Bison deterministic LALR BGB <cr88192@hotmail.com> - 2012-09-04 13:45 -0500
              Re: C include handling, was Bison deterministic LALR Marco van de Voort <marcov@toad.stack.nl> - 2012-09-05 08:40 +0000
  Re: Bison determinis​tic LALR(1) parser for Java/C++ (kind of complex langauge) without 'lexar hack' support hsad005@gmail.com - 2012-08-18 02:09 -0700

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