12 Mar
2025
12 Mar
'25
1:36 a.m.
According to Ken Thompson <kenbob(a)gmail.com>:
-=-=-=-=-=-
i find that SD and yacc have about the same
time performance. yacc gets a bad rep when
it uses lex as its front-end. then it is pig-slow.
Parsing is never a performance issue since its time is generally O(n)
where n is the number of tokens emitted by the lexer and the constant
is not large. The lexer always is because it's the only part of the
compiler that has to look at every input character separately. If a
compiler does a lot of optimization, the analysis for that can be
slow, too.
Lex was a dog. Flex, which as far as I know was a complete rewrite
that shared no code with lex, are not bad.
--
Regards,
John Levine, johnl(a)taugh.com, Primary Perpetrator of "The Internet for
Dummies",
Please consider the environment before reading this e-mail. https://jl.ly