Logic Functions

Ø @FALSE -

The logical value 0.

Ø @FILEEXISTS(S) -

1 if file S can be opened for reading; otherwise 0.

Ø @IF(X, T, F) -

The value of T if X evaluates to on-zero, or F if X evaluates to zero.

Ø @ISERROR(X) -

Returns 1 if X ``contains"" an error, otherwise 0.

Ø @ISNUMBER(X) -

1 if X is a numeric value; otherwise 0.

Ø @ISSTRING(X) -

1 if X is a string value; otherwise 0.

Ø @TRUE -

The logical value 1.