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IF

        [SIC\]IF Logical_Expression [THEN]

    Start a conditional IF block. The behaviour of IF blocks is  similar  to
    structured  Fortran.  Any  text  following the logical expression is ig-
    nored, but if this text is not THEN, an error message is produced.

    This command can only be used within a procedure: interactive users  are
    expected to be able to make their decisions themselves.

    There must be no blanks within the logical expression, but composite ex-
    pressions are allowed. Two special logical functions can also be used:
        - EXIST(VarName) Returns .TRUE. if VarName is an existing variable
        - FILE("String") Returns .TRUE. if String is an existing file.  Dou-
            ble  quotes  protect  the case of the string. Syntax FILE("'Var-
            Name'") allows to check the  string  contained  in  a  character
            variable.


Gildas manager 2011-09-07