Jaime Villate schrieb:
> Hi,
> I'm having problems with fprint, not behaving as format in Lisp.
>
> 1- Tildes can only be printed in some places and not in others:
>
> (%i1) :lisp(format t "~~ ~d" 4);
> ~ 4
> NIL
>
> (%i2) printf(true, "~~ ~d", 4);
> printf: arguments exhausted.
> -- an error. To debug this try debugmode(true);
>
Hi Jaime,
this bug is easy to fix:
/share/contrib/stringproc/printf.lisp line 85
replace
(if (search spec "}]>;%&t") (progn (setq start pos2) (go tag1)))
by
(if (search spec "}]>;%&t~") (progn (setq start pos2) (go tag1)))
I forgot to add the "~" here. I will fix this in CVS.
2- Conditional formatting fails:
> (%i3) :lisp(format t "~{~#[~;~d ~;~f ~;~a ~]~}~%" (list "numbers" 4 5));
> numbers 4.0 5
> NIL
>
> (%i4) printf(true, "~{~#[~;~d ~;~f ~;~a ~]~}~%", ["numbers", 4, 5]);
> printf: argument can't be supplied to d-directive: numbers
> -- an error. To debug this try debugmode(true);
>
>
I fear I have to say that this bug is impossible to fix in the current
implementation of printf.
printf basically uses format. Since format doesn't know a directive for
bigfloats I invented the ~h directive (h=huge) and wrote a version of
printf where each ~h directive is converted to an according ~a directive
and the corresponding bigfloat argument is converted into a formatted string
before calling format.
As a result of this concept I already had to skip the ~* directive which allows
to use arguments more than one time. In your example you effectively reorder
the arguments. This also leads into trouble.
My preprocessing the expressions before calling format needs a proper
sequential correspondence of both directives and arguments.
A way out of these problems will be an implementation of printf which uses
format only in a very basic way (just single args). But that is a long way.
I hope I can do it this year.
At the moment I can't be more helpful.
Volker
> I'm using a very recent CVS version.
>
> Regards,
> Jaime
>
>
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