Introduces a set of alternative statements in a block-if control structure.
A block-if structure consists of one or more alternative sets of statements. The first of these is introduced by an IF statement. There may then be further sets introduced by ELSIF statements. Then you can have a final set introduced by an ELSE statement, and the whole structure is terminated by an ENDIF statement. Full details are given in the description of the IF directive.
Directives: IF, ELSE, EXIT, ENDIF, CALCULATE.