BOOLEAN Expressions and if Statements

New expressions based on the operators such as EQ and GT give a BOOLEAN result that can be used directly in a PML 2 if test:

if (!NewValue - 1 GT 0) then

The expression can be a simple variable provided it is a BOOLEAN type variable:

 !Success = !NewValue GT 0

if (!Success) then

The expression could be a User-defined PML function provided it returns a BOOLEAN result:

if (!!MyFunction() ) then

Note:
The BOOLEAN constants TRUE, FALSE, YES and NO and their single-letter abbreviations not enclosed in quotes return BOOLEAN results and so can be used directly in expressions. For example:

The following do not return BOOLEAN values and are therefore invalid:

For upward compatibility with PML 1, STRING variables set to TRUE, FALSE, YES, or NO or their single-letter abbreviations can be used in an if-test as long as they are evaluated with a preceding $. For example:

There is a built-in PML method and a function for converting a value to BOOLEAN:

 !MyString = ‘TRUE’

if (!MyString.Boolean() ) then . . .

The BOOLEAN conversion is as follows: