IF...THEN...ELSE - a control flow statement that allows conditional
                   execution or branching, based on the evaluation of
                   an expression that must be either true or false
 
Block IF...THEN...ELSE Syntax
  IF booleanexpression1 THEN
     [statementblock-1]
  [ELSEIF booleanexpression2 THEN
     [statementblock-2]
  . . .
  [ELSE
     [statementblock-n]]
  END IF
    - booleanexpression is an expression that must return non-zero (true)
      or zero (false)
    - statementblock consists of any number of statements on one or more
      lines.
 
Single-line IF...THEN...ELSE Syntax
  IF booleanexpression THEN thenpart [ELSE elsepart]
    - booleanexpression is an expression that must return non-zero (true)
      or zero (false)
    - thenpart consists of the statements or branches performed when
      booleanexpression is true (see <DETAILS>)
    - elsepart consists of the statements or branches performed when
      booleanexpression is false
 
See Also  <SELECT CASE>  <ON...GOTO>  <ON...GOSUB>