Sanyo MBC-550 Series User Manual page 121

(3) <statement>{:statement>} may be a multi-statement.
(4) When IF is nested, the ELSE is assumed to be paired
with the IF immediately before. Therefore, the ELSE
cannot be omitted in nested IF statement. Only the
outermost IF statement can omit the ELSE starement.
Examples
>100 IF A<3 THEN A=A-1:C=D:H=H+2:G0T0 200 ELSE 300
>100 IF A=B GOTO 500 ELSE A=0:G0T0 600
>100 IF A=B THEN IF C<D THEN 200 ELSE 300
ELSE IF C>D THEN 400 ELSE 500
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