To help the Typechecker we have a language for specifying type of builtin variables and functions. This is needed because we cannot derive types for these variables and functions.

definitions
  constants 
    do_fortran_indexing :=  int
    e       := float
    eps     := float
    pi      := float
    ...
  variables
    warn_fortran_indexing := int
    warn_num_to_str := int
    ...
  functions
    ...
    date    :: -> string 
    time    :: -> float
    ctime   :: float -> string
    isieee  :: -> int
    fnmatch :: string, matrix(char) -> matrix(int)
    fnmatch :: string, string -> int
    ...