General Purpose PostScript Generating Utility
7. Pretty Printing
The main feature of a2ps is its pretty-printing capabilities.
Two different levels of pretty printing can be reached:
basic (normal highlight level) in which what you print is what you
string (heavy highlight level), in which in general, some keywords are
replaced by a Symbol character which best represents them. For
instance, in most languages `<=' and `>=' will be replaced by
the corresponding single character from the font Symbol.
Note that the difference is up to the author of the style sheet.