Yap.app (formerly GPSText)
(Yet another previewer)

A PostScript/PDF previewer and front end to the
a2ps text formatting tool. 
Features:
 * extensive use of OOP programming techniques
 * preview PostScript files
 * format text files with a2ps
 * opens files that are listed on the command line for easy
   previewing
 * set
   + paper size
   + pretty print style
   + prologue
   + encoding
 * set a2ps options via an easy-to-use GUI

LICENSE: GPL2 or later

WWW: http://www.gnustep.it/marko/GPSText/