02-Mar-2013 15:04, David пишет:
Am 02.03.2013 10:33, schrieb Namespace:
For one of our courses this year we have a very cool topic: Lexer and
Compiler.
In the past I have already tried some experiments in this direction with
Romulus and Remus, but I've never measured my Lexing time.
That's why I wanted to start again to write a lexer (hitherto purely for
the learning effect).
I looked at the code of some of the other lexers, that are also written
in D, to get some inspiration from, but currently my Lexer is a little
bit slow, it requires for example ~200 msecs for std.datetime.
So I wanted to ask whether there are nice people who help me to improve
our lexer.
Code: https://github.com/Dgame/Puzzle/blob/master/lexer.d
Thanks in advance. :)
Making `types` and `keywords` an array might improve the speed a little bit:
if (id in types) -> if (types.canFind(id))
(same with keywords)
That would be slower as canFind is linear search.
Simpler way is use first letter and length to select a bucket of keywords.
But otherwise, yes, the first advice is never use built-in AA as these
take quite some time to allocate. Plus they not that fast to lookup as
they used mod-prime not mod-power-of-2 to pick a bucket.
--
Dmitry Olshansky
