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IF

        [SIC\]IF Logical_Expression [THEN]
        [SIC\]IF Logical_Expression Command [Arguments]

    The first form starts a conditional IF block. The behaviour of IF blocks
    is similar to structured Fortran. The THEN keyword is optional.
    The  second  form  defines a logical IF statement, i.e. it uses a single
    line with no possibility of alternate execution (no ELSE  choice).  When
    the argument following the logical expression is not THEN, it is assumed
    to be a command which will be interpreted, together with the next  argu-
    ments, if the logical expression evaluates as true.

    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.
          This function may complain about invalid filename.  For  a  silent
          alternative, see
          COMPUTE Logical IS_A_SIC_VAR String
      - FILE("String")  Returns .TRUE. if String is an existing file. Double
          quotes protect the case of the  string.  Syntax  FILE("'VarName'")
          allows to check the string contained in a character variable.


Gildas manager 2015-03-19