Hi, Recent changes in PetitParser have caused parsing to slow down by a factor of 15-20. Here is an example run on freshly downloaded Moose image: [|string allStyles text| string := (PharoFilesOpener default changesFileOrNil contents copyFrom: 1 to: 60000). text := string asText. allStyles := { 'Announcement' -> TextColor green. 'Collections' -> TextColor blue. 'File' -> TextColor blue. 'Metacello' -> TextColor red. 'Monticello' -> TextColor magenta. 'Morphic' -> TextColor orange. 'Mooose' -> TextColor green. 'FAMIX' -> TextColor green. 'Roassal' -> TextColor green. }. allStyles do: [ :assoc | ((assoc key asParser, #newline asParser negate star) matchingRangesIn: string) do: [:aRange | text addAttribute: (assoc value) from: aRange first to: aRange last] ]. text] timeToRun ==> 15 sec ============== now do this: Gofer new url: 'http://smalltalkhub.com/mc/Moose/PetitParser/main'; version:'PetitParser-DiegoLont.233'; load. and run the example again. timeToRun ===> 2 sec So, we need to have a look at what is added recently in PetitParser that is making it slow down quite significantly because the for the larger systems, this can be enormous. regards, Usman P.S: Tests run on OS X 10.9.4, 2.3 GHz, 8 GB RAM, HD SSD.