[mercury-users] Translating from Prolog

[hanberg at ruc.dk]

Hi again

I haven't really made it work - what I would like to have translated is:

closes(X & Y) :- closes(X), closes(Y).
closes(~~X) :- closes(X).

I've tried doing this(and a lot more):

:- type &(X, Y) ---> X & Y.
:- type ~(X) ---> ~X.

:- pred closes(_).

:- mode closes(in).

:- closes(X & Y) --> closes(X), closes(Y).
:- closes(~~X) --> closes(X).

But this doesn't seem to work - I must do someting simple wrong, but I have no
idea what.

Thank you very much for your help.

Tony

 

Quoting hanberg at ruc.dk:

> Quoting David Overton <dmo at cs.mu.OZ.AU>:
> 
> > On Mon, Jun 07, 2004 at 04:51:02PM +0200, hanberg at ruc.dk wrote:
> > > I'm a Mercury newbie and would really like help to translate the
> following
> > from
> > > Prolog to Mercury:
> > > 
> > > :- op( 500, xfy, &).
> > > :- op( 400, fy, ~).
> > 
> > Mercury does not allow you to change the precedence of operators.  Its
> > builtin definitions for & and ~ are
> > 
> > :- op( 1025, xfy, &).
> > :- op( 900, fy, ~).
> 
> Ok, I didn't know that they already were defined, since I tried using them
> and
> couldn't make it work.
> 
> > 
> > so you are stuck with those.
> > 
> > > closes(~(X & Y)) :- closes(~X), closes(~Y).
> > 
> > You can use this clause as is.  You will need to define a type
> > containing your functions `~' and `&', and give type and mode
> > declarations for closes/1.
> 
> I tried looking in the tutorial and on the Internet, but I can't really
> make
> that work. What would you write in a case like this?
> 
> > 
> > 
> > David
> > -- 
> > David Overton
> > WWW: http://www.overtons.id.au/
> > Mobile Phone (UK): +44 7799 344 322
> >
> --------------------------------------------------------------------------
> > mercury-users mailing list
> > post:  mercury-users at cs.mu.oz.au
> > administrative address: owner-mercury-users at cs.mu.oz.au
> > unsubscribe: Address: mercury-users-request at cs.mu.oz.au Message:
> > unsubscribe
> > subscribe:   Address: mercury-users-request at cs.mu.oz.au Message:
> subscribe
> >
> --------------------------------------------------------------------------
> > 
> Thank you for your help!
> 
> Tony
> 
> --------------------------------------------------------------------------
> mercury-users mailing list
> post:  mercury-users at cs.mu.oz.au
> administrative address: owner-mercury-users at cs.mu.oz.au
> unsubscribe: Address: mercury-users-request at cs.mu.oz.au Message:
> unsubscribe
> subscribe:   Address: mercury-users-request at cs.mu.oz.au Message: subscribe
> --------------------------------------------------------------------------
> 


--------------------------------------------------------------------------
mercury-users mailing list
post:  mercury-users at cs.mu.oz.au
administrative address: owner-mercury-users at cs.mu.oz.au
unsubscribe: Address: mercury-users-request at cs.mu.oz.au Message: unsubscribe
subscribe:   Address: mercury-users-request at cs.mu.oz.au Message: subscribe
--------------------------------------------------------------------------