Lexer and parser generators using CTFE
bcs at example.com
Tue Feb 28 22:05:21 PST 2012
On 02/27/2012 11:59 PM, Andrei Alexandrescu wrote:
> I'm starting a new thread on this because I think the matter is of
> strategic importance.
> We all felt for a long time that there's a lot of potential in CTFE, and
> potential applications have been discussed more than a few times,
> ranging from formatting strings parsed to DSLs and parser generators.
> Such feats are now approaching fruition because a number of factors
> * Dmitry Olshansky's regex library (now in Phobos) generates efficient D
> code straight from regexen.
> * The scope and quality of CTFE has improved enormously, making more
> advanced uses possible and even relatively easy (thanks Don!)
> * Hisayuki Mima implemented a parser generator in only 3000 lines of
> code (sadly, no comments or documentation yet :o))
A bit outdated but....
BTW, that uses very little in the way of CTFE and even less in the way
of string mixins. Those are, IMHO, very powerful tools that should only
be combined as weapons of last resort.
> * With the occasion of that announcement we also find out Philippe
> Sigaud has already a competing design and implementation of a parser
> This is the kind of stuff I've had an eye on for the longest time. I'm
> saying it's of strategic importance because CTFE technology, though not
> new and already available with some languages, has unique powers when
> combined with other features of D. With CTFE we get to do things that
> are quite literally impossible to do in other languages.
> We need to have a easy-to-use, complete, seamless, and efficient
> lexer-parser generator combo in Phobos, pronto. The lexer itself could
> use a character-level PEG or a classic automaton, and emit tokens for
> consumption by a parser generator. The two should work in perfect tandem
> (no need for glue code). At the end of the day, defining a complete
> lexer+parser combo for a language should be just a few lines longer than
> the textual representation of the grammar itself.
> What do you all think? Let's get this project off the ground!
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