break-even point

break-even point n.  In the process of implementing a new
   computer language, the point at which the language is sufficiently
   effective that one can implement the language in itself.  That is,
   for a new language called, hypothetically, FOOGOL, one has reached
   break-even when one can write a demonstration compiler for FOOGOL
   in FOOGOL, discard the original implementation language, and
   thereafter use working versions of FOOGOL to develop newer ones.
   This is an important milestone; see {MFTL}.

   Since this entry was first written, several correspondents have
   reported that there actually was a compiler for a tiny Algol-like
   language called Foogol floating around on various {VAXen} in the
   early and mid-1980s.