Re: Bug or feature of Eclipse 5.2

From: Joachim Schimpf <>
Date: Thu 09 Aug 2001 11:13:27 AM GMT
Message-ID: <>
Manuel Weindorf wrote:
> so the follwing question answered yes (as expected)
> ?- phrase( digit, ['1'], [] )
> Now I updated to Eclipse 5.2 and the same question  answeres
> ?- phrase(ziffer, ['1'], []).
> More (0.00s cpu)
> No (0.02s cpu)
> How is that possible ?

It is a feature, and it is not related to DCGs :-)
The behaviour of your program hasn't changed, just
the results are displayed differently.

The 'More' answer generally means
'Yes, and there may be more solutions'.

The system prints 'More' instead of 'Yes' when it cannot
determine that the solution is the last one (in more
technical terms: when the goal has left a choice point).
Apart from this additional piece of information, 'Yes'
and 'More' are completely equivalent.

In versions before 5.2 the 'More' was suppressed in the
special case that the goal contained no variables (as
in your example). If you add some variable, the 'More'
is printed even in version 5.1:

Version 5.1.3, Sat May 12 01:10 2001
[eclipse 2]: phrase( digit, ['1'], [] ).

[eclipse 3]: phrase( digit, ['1'], [] ), X = X.

X = X     More? (;) 

no (more) solution.

In 5.2 we have removed this somewhat confusing rule and
now always print 'More' even if there are no variables
in the query.

For users of tkeclipse: this more-prompt corresponds exactly
to the more-button in tkeclipse. An active more-button means
there may be more solutions, a grey button means there are none.

 Joachim Schimpf              /             phone: +44 20 7594 8187
 IC-Parc, Imperial College   /  
 London SW7 2AZ, UK         /
Received on Thu Aug 09 12:14:07 2001

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