From salzer@logic.at Fri Oct 26 12:26:30 2001
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Date: Fri, 26 Oct 2001 12:26:24 +0200
From: Gernot Salzer <salzer@logic.at>
Message-Id: <200110261026.f9QAQOD19771@alpha.logic.tuwien.ac.at>
To: prolog@swi.psy.uva.nl
Cc: salzer@logic.at
Subject: [SWIPL] Type error vs. silent failure

[ Sorry, must have been discussed in the past, but couldn't find anything ]

Is there any rational behind      
   nth1(a, [a,b,c], X).
failing silently and
   length([a,b,c], a).
giving a type error?

The question is not whether one an tweek SWI-Prolog (or some other Prolog)
to behave one way or the other, but what I can savely assume
as a programmer when writing a portable program (as much as possible).

Thanks, Gernot

