Re: [eclipse-users] Interval constraints

From: Kish Shen <kish_at_...2...>
Date: Thu, 30 Aug 2007 21:32:37 +0100
Wojciech Pieprzyca wrote:
> Dear all,
>
> In the tutorial of ECLiPSe I currently study, there is the following
> example at chapter 8:
>
> ?- X :: -10 .. 10.
>
> In my ECLiPSe version when I copy out it literally I get an error:
> string stream 27: syntax error: postfix/infix operator expected
> | [X]::-1..10
> |      ^ here
>
>   
I only get the exact error you are getting (with lib(ic) loaded) if I 
type in

[eclipse 2]: [X] ::-10..10.
syntax error: postfix/infix operator expected
| [X] ::-10..10.
|       ^ here
[eclipse 2]:

The important difference between this and what is in the tutorial is the 
space between :: and the -10.
The parser gets confused by the if there is no space between :: and the 
-, because this can be a
: operator folllowed by the :- operator.

> I found that probably the parentheses are missed because if I try to run
> ?- X ::(-10 .. 10).
> it works fine. For positive numbers (without minus ahead) both version 
> work correctly.
>
>   
In this case the bracket serves as a seperator between the -10 and the 
::, so that why it works.

Cheers,

Kish
> Is it the real cause of the problem ?
>
> Best regards,
> Wojciech Pieprzyca
>
>
> _______________________________________________
> ECLiPSe-Users mailing list
> ECLiPSe-Users@...2...
> http://www.crosscoreop.com/mailman/options/eclipse-users
>   
Received on Thu Aug 30 2007 - 21:32:46 CEST

This archive was generated by hypermail 2.2.0 : Mon Jul 09 2018 - 02:05:29 CEST