Optimizing pattern matching

Optimizing pattern matching – a nicely illustrated little blog by Julien Desgats , with animations of transformations on Abstract Syntax Trees. Though this has little to do with RISC OS (apart from the fact that RiscLua has Lpeg) it may appeal to forum readers interested in a problem of pure computer science .

Suppose you are searching text for the words bar , foo , or baz , in that order of priority. The corresponding Lpeg pattern is

P'bar' + P'foo' + P'baz'

 P'ba'*(P'r' + P'z') + P'foo' 

aaaa