On Apr 11, 9:52 am, idbax...@[EMAIL PROTECTED]
wrote:
> The other limitations: no left recursion, no ambiguity, are all solved
> by good parser generators. I highly recommend GLR, which is what we
> use for DMS. None of the above limitations apply.
Isn't GLR exponential in the worst case? I settled on CYK. Three
nested loops, even a sloppy programmer like me can implement that!
Then there are optimization tricks to speed things up a little...
I also checked Earley, but [contrary to what literature suggests] I
was unable to make it competitive to CYK. CYK optimizations clearly
fail to apply to Earley, and unlike CYK where syntactically incorrect
input still can be processed into a forest I failed to figure out how
to do error recovery for Earley.
> > Within a wider perspective I feel a general failure of parser
> > technology to deliver a user friendly product. This is why we have
> > horrors of XML filling the void.- Hide quoted text -
>
> I continually am amazed that people get hung up on the parsers. I
> guess they just never get past it.
>
> For any really interesting langauges, like poker, you have to ante up
> a parser, that isn't where the real problems are. You need tree
> building, preprocessor sup****t, multiple compilation unit sup****t,
> name/type resolution, control/data flow analysis, semantic analysis
> based on that awful reference manual for that screwball dialect, ....
>
> And having spent a decade implementing integrated machinery to do all
> this, I don't see how anybody can justify rolling their own whatzit.
Again this is true for well packaged products, and I don't see them on
the market. The mature and best do***ented products like ANTLR suffer
from the above deficiencies, while GLR, Earley, or CYK based parser
engines are rare, experimental and likely be unavailable for
implementation language of my choice.
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