[Kst] New equation parser and interpreter
staikos at kde.org
Fri Feb 13 00:12:34 CET 2004
On Thursday 12 February 2004 18:02, Barth Netterfield wrote:
> What did you do?
I rewrote it from scratch. :-) It uses a parser and scanner written in yacc
and flex, and "compiles" the equation into a tree. Then you take the root
node of the tree and call ->value(&ctx), which recursively evaluates the
equation. This means that parsing of anything in the equation only ever
happens once, and we can even optimize it later (constant folding,
Actually there are faster constructs yet, but I don't think it's worth the
bigger effort and more complex code it results in. I need to finish adding
functions, constants, and a few other minor items and I can switch
KstEquationCurve over completely.
I have a long list of other items (not related to KstEquation) that need to
be dealt with too. I'm going through them quickly, but some are very complex
and we need to discuss. Actually threading is looking to be a requirement
now. After experimenting with the event loop in Kst this week, I have found
a very large number of ways to crash Kst. I don't think there's much we can
do about it without moving things over to a threading model (and adding
locks). It might be worthwhile to have a second stab at the threading branch
and trying to optimize it.
quite cool. :-) I'm just waiting for a particularly complex fix from the
KJSEmbed author and the changes will become very visible.
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