
ERRORLEVEL - controls error testing during evaluation

Calling sequence:

ERRORLEVEL := integer

Parameter:

integer   --  one of the numbers 0, 1, 2 or 3

Summary:

ERRORLEVEL is an environment variablethat controls evaluation. The parameter
integer gives the accuracy of the testing. At the present time only the levels
0 and 3 are implemented. If 1 or 2 are given the the level 0 is chosen internally.

With level 0 only a short error test takes place. This hardly influences the
system speed at all.  With this level those errors are not found that can
occur during the substitutionof identifiers, indexed expressions and calls of
user-defined procedures.

In level 3 the system has extra work finding all errors during evaluation. This
can reduce the system speed.

Through the assignment of NIL ERRORLEVEL is set to its default value 0.

>>  f(a) := {a}: f(a) and a;

     {a} and a

>>  ERRORLEVEL := 3: f(a) := {a}: f(a) and a;

      Warning: Incompatibel operands

