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From: Paul Johnson <Paul@treetop.demon.co.uk>
Subject: Re: Building blocks (Was: Design By Contract)
Date: 1997/10/04
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 <199710011402.QAA02444@basement.replay.com> <3432788C.E35@uk.ibm.com>
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Date: 1997-10-04T00:00:00+00:00
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In article <3432788C.E35@uk.ibm.com>, Paul M Gover
<Paul_Gover@uk.ibm.com> writes

>(One of the while-loop problem is that for a tidy
>record processing program you have to write
>       record = file.read()
>       Do while(~file.eof())
>               thing.accept(record)
>               record = file.read()
>       End while
>)

I know that this was an aside, but it still puzzles me.  Surely it will
be wrong if the file is empty: there will be no record to read.  The
correct version (in Eiffel) would be

   from file.open("foo") until file.eof loop
      thing.accept (file.record)
   end -- loop

If you have to read a dummy record before file.eof becomes valid then
you have a badly designed file object.

Paul.

--------------------------------+---------------------------------
Paul Johnson                    | You are lost in a maze of twisty
Email: Paul@treetop.demon.co.uk | little standards, all different.
       paul.johnson@gecm.com    |