Improving KDevelop-PG-Qt (October 26, 2009)
Good news everyone :)
Documentation
After years of pretty much no documentation (except looking at the sources… ), The_User aka. Jonathan Schmidt-Dominé started documenting the parser generator that is used for most KDevelop language plugins (java, python, php, …). You can find it here: http://techbase.kde.org/Development/KDevelop-PG-Qt_Introduction
It has to be improved and more examples have to be put in there, but it’s already a huge improvement over the situation before…
Performance
In related news I did some profiling on the parsing of the quite big file that includes all internal PHP declarations (i.e. all functions, classes, definitions,…). It drops in at a whopping 1.9M, with ~80k lines. Well, turns out that this showed a pretty easy to fix bottleneck in KDevelop-PG’s LocationTable, which used to use a linear lookup algorithm. Profiling showed that nearly 75% was spent in that function. But I used the past tense for a reason:
I replaced it with an algorithm that combines a relative search (i.e. relative to the last lookup) with a binary search fallback. That’s comparatively blazingly fast. I added some benchmarks to KDevelop-PG-Qt that proofs that (benchmark below run with release mode build):