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From: billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu (William Thomas Wolfe, 2847 )
Newsgroups: alt.cobol,comp.lang.ada,comp.infosystems
Subject: Re: What's really wrong with COBOL?
Message-ID: <8471@hubcap.clemson.edu>
Date: 23 Mar 90 16:43:08 GMT
References: <4877@ganymede.inmos.co.uk>
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>From mph@lion.inmos.co.uk (Mike Harrison):
> Yes, the Ada specifications do provide a sort of interface contract, 
> but they only enforce the *syntactic* (and perhaps *static* semantic) 
> aspects of the interface...  There is however, no support for checking 
> the *dynamic* semantics of the interface...

   To completely check the semantics of the interface is probably so
   computationally complex as to be not realistically achievable.  But
   practically speaking there is a way to let Ada help you here as well.

   Simply temporarily *remove* the modified procedure or function from
   the specification and recompile.  Then the Ada compiler will point out
   *all* places at which the modified procedure or function was referenced.

   Now recompile the "complete" specification, and verify that all the 
   points at which the semantically modified procedure or function was 
   referenced are OK with respect to the semantic modification.  This
   has the disadvantage of perhaps being overconservative -- leading you
   to points at which the semantic change may not actually do any harm --
   but it's certainly better than manually trying to track the effects of
   the change, and in all probability it's the most practical solution.
    

   Bill Wolfe, wtwolfe@hubcap.clemson.edu