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Re: Anomalous results from is-a? and instance? on current-input-port

From: Mikael Djurfeldt
Subject: Re: Anomalous results from is-a? and instance? on current-input-port
Date: Wed, 16 Feb 2005 12:20:07 +0100

On Tue, 15 Feb 2005 18:39:44 -0500, Alan Grover <address@hidden> wrote:
> Guile 1.6.4
> Linux xxxx 2.6.5-7.145-default #1 Thu Jan 27 09:19:29 UTC 2005 i686 i686
> i386 GNU/Linux
> SuSe 9.1
> Some instance and class introspection procedures give anomalous results.
> Specifically, they seem to give false when they shouldn't.
> My results (from code below, just for current-input-port). Note the #f's":
> ; from interactive guile
> (class #<<class> <soft-input-port> 8087280>
>   instance? #f
>   (is-a? <soft-input-port>) #f
>   class-direct-supers (#<<class> <soft-port> 80872b0> #<<class>
> <input-port> 8084110>)
>   (is-a? <input-port>) #t
> Results are repeatable if tried in the same interactive interpreter, or
> run from a script. However, I get the following variations:
> * Run from a script: (is-a? <soft-input-port>) #t
> * Use my .guile: (is-a? <soft-input-port>) #t

* instance? should give #f since the port is not a normal GOOPS
instance but rather a built-in datatype.

* the class-direct-supers list looks OK

* (is-a? <input-port>) gives the correct value #t

The only thing anomalous above is that (is-a? x <soft-input-port>)
gives #f in the interpreter.
I can't repeat that in the development version, so it seems specific
to Guile-1.6.4. Can someone else look into that?


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