IF expr THEN GOTO linenbr | label
Evaluates the expression ‘expr’ and performs the THEN statement if it is true or skips to the next line if false. The optional ELSE statement is the reverse of the THEN test. This type of IF statement is all on one line.
The ‘THEN statement’ construct can be also replaced with:
GOTO linenumber | label
IF THEN ELSE
IF THEN ELSE ELSIF ENDIF