[Haskell-cafe] Alex Lexer Performance Issues
malcolm.wallace at me.com
Sun Jun 26 12:19:32 CEST 2011
On 22 Jun 2011, at 15:53, Tristan Ravitch wrote:
> On Wed, Jun 22, 2011 at 07:48:40AM +0100, Stephen Tetley wrote:
>> How fast is good old String rather than ByteString?
>> For lexing, String is a good fit (cheap deconstruction at the head /
>> front). For your particular case, maybe it loses due to the large file
>> size, maybe it doesn't...
> I gave it a shot and the percentages in the profile are approximately
> the same (and peak memory usage was about double). I might end up
> having to parse the original binary format instead of the text format.
There is an old folklore that lexing is usually the most expensive phase of any compiler-like traversal. 50% of time and space expended on lexing was pretty common twenty years ago.
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