Message-ID: <323EFCE6.50A5@mail.amsinc.com>
Date: Tue, 17 Sep 1996 12:32:54 -0700
From: Tom Hawker <thawker@mail.amsinc.com>
Organization: AMS, Incorporated
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Subject: Re: A bug (or misfeature) in the VW compiler
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Ralph Johnson wrote:
> 
> ...  I think
> that blocks with no bodies are bizarre, and I have never seen one used,
> except in pluggable adaptors to define an action that does nothing.

Which is precisely the most useful thing about them.

I don't understand the bru-ha-ha about empty blocks.  They are perfect for
code stubs when you're not sure what you want to do (or the code to use is
not available yet).  And as you pointed out, they are about the only choice
where you have an argument whose interface protocol expects a block, but in
which you want nothing to happen when invoked.

I remember asking about the ParcPlace implementation's behavior a long time
ago, say 1987, and the explanation Alan Lovejoy gave is what they gave to
me:  it's always been this way.  If the language standard says something to
the contrary, we should request PPDT conform to the spec and not to history.

Tom Hawker
