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From: vsnyder@math.jpl.nasa.gov (Van Snyder)
Subject: Two ideas for the next Ada standard
Date: 1996/08/28
Message-ID: <5009h5$ir4@netline-fddi.jpl.nasa.gov>#1/1
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organization: Jet Propulsion Laboratory
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newsgroups: comp.lang.ada
Date: 1996-08-28T00:00:00+00:00
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1.  Allow the "mode" of an "access to procedure" or "access to function"
    formal argument to be "limited".  Interpret this to mean "you can only
    use this argument to access the subprogram, or pass it as an actual
    argument to a formal argument of `limited' mode."  This would prevent
    one from storing the "pointer" into an "access to procedure" variable,
    and thereby allow safely passing internal procedures as actual arguments.

2.  Allow an "out" "mode" for variables in specification parts, or fields
    in records.  The interpretation is that any one can read the variables,
    but only procedures in (or the initialization part of) the body of the
    package can write them, or pass them to other than "in" mode formal
    arguments in different packages.  Given this, one can safely expose
    variables containing values one wishes to expose, but to which one does
    not want to permit willy-nilly changes, without the need to write a
    one-line function.
-- 
What fraction of Americans believe   |  Van Snyder
Wrestling is real and NASA is fake?  |  vsnyder@math.jpl.nasa.gov