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From: db@lfcs.ed.ac.uk (Dave Berry)
Newsgroups: comp.lang.misc
Subject: Re: What I'd really like to see in an if-statement...
Message-ID: <126@castle.ed.ac.uk>
Date: 15 Aug 89 11:13:32 GMT
References: <8577@batcomputer.tn.cornell.edu> <14251@haddock.ima.isc.com> <516@brazos.Rice.edu> <14278@haddock.ima.isc.com> <1989Aug14.022903.22953@agate.berkeley.edu>
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Reply-To: db@lfcs.ed.ac.uk (Dave Berry)
Organization: Laboratory for the Foundations of Computer Science, Edinburgh U
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In article <1989Aug14.022903.22953@agate.berkeley.edu> mwm@eris.berkeley.edu (Mike Meyer) writes:
>
>The Icon group find a slightly cleaner way to do this. Instead of
>expression evalutaing to booleans, they either produce a value, or
>"fail". Any expressions including a failed expression also fail, except
>for "not" (which is classed as a control structure).
>
>Likewise for:
>
>	if a < b <= c = d < e then


What about  (a < b) = (d < e), i.e. comparing results of relational
operations?  Presumably this is equivalent to

	if a < b and d < e then b = e [else fail]

and not to the expected result from boolean logic.  Or does bracketing
a relational expression force it to produce a canonical truth value (ugh) ?

Dave Berry, Laboratory for Foundations      db%lfcs.ed.ac.uk@nsfnet-relay.ac.uk
    of Computer Science, Edinburgh Uni.	    !mcvax!ukc!lfcs!db

      Rhetoric 101: Use of "scare" quotes and the phrase "so-called".