The Free On-line Dictionary of Computing (19 January 2023):

A Language with an Extensible Compiler
ALEC

    (ALEC) A language Implemented using RCC on an
   ICL 1906A.

   ["ALEC - A User Extensible Scientific Programming Language",
   R.B.E. Napper et al, Computer J 19(1):25-31].

   (1995-04-19)