Re: Remarks on SWI 7

Ulrich:
>Jan Wielemaker:

>>A standard that _prescribes_ that length(2,0) should fail silently is
>>something I refuse to take seriously.  So yes, it is another issue.
>
>On the other hand you leave out many list checks in many places - not
>even consistently - and sometimes add errors not described in the
>standard.  Your main argument being (against checks), that these tests
>are so costly.  So people cannot anticipate what will happen without
>trying SWI or studying its source code.  Or they just od the right
>thing without ever getting errors.


To the working programmer this 100% isn't an issue, because I won't write 
code with anything other than length(List, Int). 
If I accidentally do I spot the error and rewrite.

So adding a 3rd clause to length as "length(_,_) :- throw" is merely helpful
and never harmful because *nobody* wants to use length on integers.

So yes it's non-compliant, but focus your efforts where it has an impact.