Re: how does print-to-codes work?

[Daniel Diaz]

Try to use get_print_stream/1 inside your portray predicate: like:

portray(F) :-
        float(F),
        format_to_codes(Fs, "~6f", [F]),
        append(Ns, Os, Fs),
        \+ (member(Ch, Os), \+ member(Ch, "0.")), !,
        get_print_stream(Stream),
        format(Stream,"~s",[Ns]).


This should work



Jasper Taylor wrote:
> 
> I have made a procedure that tidies up the printing of floats and it works OK
> if consulted as portray/1 for the built in print predicate. But if I use
> print_to_codes the result of portray/1 is still sent to the console. Here's
> an example...
> 
> $ gprolog
> GNU Prolog 1.2.14
> By Daniel Diaz
> Copyright (C) 1999-2002 Daniel Diaz
> | ?- print(2.92).
> 2.9199999999999999
> 
> yes
> | ?- print_to_codes(A, 2.92).
> 
> A = [50,46,57,49,57,57,57,57,57,57,57,57,57,57,57,57,57,57]
> 
> yes
> | ?- consult(nicefloat).
> compiling /win98/Program Files/Simile/Develop/Tests/nicefloat.pl for byte
> code...
> /win98/Program Files/Simile/Develop/Tests/nicefloat.pl compiled, 6 lines read
> - 1503 bytes written, 8 ms
> 
> yes
> | ?- portray(2.92).
> 2.92
> 
> yes
> | ?- print(2.92).
> 2.92
> 
> yes
> | ?- print_to_codes(A, 2.92).
> 2.92
> 
> A = []
> 
> yes
> | ?-
> 
>   ------------------------------------------------------------------------
>                    Name: nicefloat.pl
>    nicefloat.pl    Type: Perl Program (application/x-perl)
>                Encoding: 7bit

--
Ce message a subi une analyse antivirus 
par MailScanner ; il est vraisemblablement
sans danger.