scheme problem!

scheme problem!

[Stefan Israelsson Tampe]

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Somewhere in the program I have,

(pk x)
(pk (caar l))
(pk (equal? x (caar l)))

It outputs

;;; (number)

;;; (number)

;;; (#f)



#f ???? is there more to this then meets the eye?
/Stefan

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Re: scheme problem!

[Pierpaolo Bernardi]

On Thu, May 12, 2011 at 12:59, Stefan Israelsson Tampe
<stefan.itampe@gmail.com> wrote:
> Somewhere in the program I have,
>
> (pk x)
> (pk (caar l))
> (pk (equal? x (caar l)))
>
> It outputs
>
> ;;; (number)
>
> ;;; (number)
>
> ;;; (#f)
>
>
>
> #f ???? is there more to this then meets the eye?

You will get more significative replies if you post a snippet of code
which allows people to reproduce what you observe without having to
guess what could possibly be causing this.

P.

Re: scheme problem!

[Neil Jerram]

Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:

> Somewhere in the program I have,
>
> (pk x)
> (pk (caar l))
> (pk (equal? x (caar l)))
>
> It outputs
>
> ;;; (number)
>
> ;;; (number)
>
> ;;; (#f)
>
>
>
> #f ???? is there more to this then meets the eye?
> /Stefan

Well...

scheme@(guile-user)> (equal? 'number (make-symbol "number"))
$7 = #f

Is it possible that either or both of x and (caar l) is uninterned?

(As far as I recall, it's intended that uninterned symbols are
distinct.)

        Neil

Re: scheme problem!

[Stefan Israelsson Tampe]

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Oh well, I found the issue.

It was because of my special system. The printed representation of unify
variables
that point to a point to a point to a symbol got printed as a symbol. I
really need to tweak
the output to hint if it is a unify variable. And if wingo managed to
squeeze in tagging - so
much sweeter.

Anyway I have implemented

Subtypes
Parameter types
Recursive types
============

Now, the subtypes have been tested a little, the rest remains to be
debugged.
Also there is a weak key map of functions to types of the object that I use
to
record type signatures.

/Stefan

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