IF (statement)

Allows other statements to be conditionally executed

COMMAND SYNTAX

    IF expression THEN | ELSE statements

SYNTAX ELEMENTS

It evaluates the expression to a value of Boolean TRUE or FALSE. If the expression is TRUE executes then the statements defined by the THEN clause (if present). If the expression is FALSE executes the statements defined by the ELSE clause.

The THEN and ELSE clauses may take two different forms being single and multiple line statements.

The simplest form of either clause is of the form:

    IF A THEN CRT A

Or

    IF A ELSE CRT A

However, expand the clauses to enclose multiple lines of code using the END keyword as so:

    IF A THEN
        A = A*6
        CRT A
    END ELSE
        A = 76
        CRT A
    END

You can combine the single and multi-line versions of either clause to make complex combinations of the command. For reasons of readability it is suggested that where both clauses are present for an IF statement that the same form of each clause is coded.

NOTES

IF statements can be nested within either clause to any number of levels.

EXAMPLE

    CRT "Are you sure (Y/N) " :
    INPUT Answer, 1_
    IF OCONV (Answer, 'MCU') = "Y" THEN
        GOSUB DeleteFiles
        CRT "Files have been deleted"
    END ELSE
        CRT "File delete was ignored"
    END