The files in source/simulator/builtins implement the builtin predicates and
operations of lambda Prolog. 

builtins.h{c}
=============
  Defines the builtin dispatching table and dispatching function.


meta.h{c}
=========
  Implements meta-level functions solve, not and unify.


evalexp.h{c}
===========
  Implements evaluation of builtin operators. 


compexp.h{c}
============
  Implements comparison predicates.


io.h{c}
=======
  Implements build-in io-related predicates.


readterm.h{c}
=============
  Defines functions for creating a term (and its type) onto simulator heap
  according to the parsing result of the compiler. The term (type) creation
  functions should be invoked by the OCaml function readTermAndType in
  source/front/readterm.mli{ml}.