COMPUTE IS_A_SIC_VAR

        [SIC\]COMPUTE OutVar IS_A_SIC_VAR InVar

    Determines whether InVar (Character string) is the name of  an  existing
    SIC Variable or not.  OutVar must be a scalar Logical variable.

    The functionality is similar to the build-in SIC function EXIST, but EX-
    IST would complain about invalid filenames as  arguments.   Here,  InVar
    can be any arbitraray string.

    This  command  is used in some scripts to determine silently whether its
    arguments are File names, variable names or other expressions (see  e.g.
    p_load.greg for an application.)