UWN

You are not at fault for this particular error. Very good find! (It's hard to narrow it down any further, because then also some other issues arise...) That said, there...

Here is a smaller 'version' of your program. ``` :- use_module(library(clpz)). :- dynamic(member_at_position/0). member_at_position :- ( M = 0 ; false ), N in 1..2, N #= M+1. :- initialization((...

At least that last error occurs also when using `freeze/2` in the remaining fragment of your program.

(it seems you are reading this here by e-mail. If you are reading it via the [web-interface](https://github.com/triska/clpz/issues/16) you see any mentioning in other places directly.)

> I realise clpfd is not the same as clpz though. clpfd in SWI is the predecessor to clpz with about 2 (CPU-)centuries of [testing](http://www.complang.tuwien.ac.at/ulrich/swi-prolog/item3addendumORIG). Unfortunately, SWI got [non-conforming](http://www.complang.tuwien.ac.at/ulrich/iso-prolog/SWI7_and_ISO) and...

Maintaining a set of specific test cases is a very tiresome activity. But, why don't you give it a try? With a fresh look on it.

@JCumin : Still not using clpz?

@JCumin - so you did not even take the offer?? For the top level, I do agree - but at least it has better naming of variables.

> at least assemble a list of requirements SWI should meet in order to add compatibility in the future Further items: - [ ] standard conformance. [By giving up conformance...

> Why would porting clpz to SWI require ISO conformance? @wouterbeek A reliable porting procedure requires testing. And that's where ISO conformance comes into play (see above post) - in...