A parser written from scratch by an individual for use in a particular game. Most modern IF, by contrast, makes use of an already-written parser which is part of a pre-existing authoring system.
- Homebrew Parsers in the IF Gems review quotes collection (also available from the IF Archive).
- Discussions about writing IF in a general programming language on the rec.arts.int-fiction newsgroup.
- The PAW Reservoir by Nacho A. Llorente.