Possible feature: consider aliases when reading namespace-qualified keywords.

[Jason Wolfe]

I've been doing some OO-type Clojure programming, and have run into
the following (quite minor) annoyance:

I've defined a struct with a :class of ::Foo in namespace
my.long.namespace.foo.

In another namespace my.long.namespace.bar, I want to define a
subclass of this struct.
In this namespace, I require [...foo :as foo], so that I can refer to
multimethods like foo/method1.

However, it seems I'm still required to write
(derive ::Bar :my.long.namespace.foo/Foo)
when I'd like to write
(derive ::Bar :foo/Foo)

I'm not sure if this is even feasible, since given my limited
experience it seems that aliases for symbols are handled at resolution-
time and not read-time, and that wouldn't work for keywords. On the
other hand, this state of affairs seems to be possibly-confusing and a
perhaps-needless difference between symbols and keywords. What do
others think about this?

Thanks,
Jason

[David Nolen]

My OO example from earlier deals with this case by completely removing any need to manually derive tags.  This is done by having CLJOS keep it's own internal hierarchy (via make-hierarchy) rather than using the default one.  By modifying metadata on the vars holding structs created by defclass (using alter-meta!) and tagging instances as described in existing Clojure literature you can provide functions to shuffle away the annoyance of dealing with keywords and their namespaces entirely.

[Jason Wolfe]

Hi David,

Thanks ... I just looked at CLJOS, and was actually just earlier
thinking about writing something similar myself. It looks very nice,
and I very well might end up using it (especially if it gets up-to-
speed with "struct"). Still, I stand by my feature request :).

I guess in the mean-time I could use symbols instead of keywords for
my class types. However, I assume that would slow things down
substantially (unless method caching would take care of this; I'll
have to check on that.)

-Jason

On Jan 19, 7:49 pm, David Nolen <dnolen.li...@gmail.com> wrote:
> My OO example from earlier deals with this case by completely removing any
> need to manually derive tags.  This is done by having CLJOS keep it's own
> internal hierarchy (via make-hierarchy) rather than using the default one.
>  By modifying metadata on the vars holding structs created by defclass
> (using alter-meta!) and tagging instances as described in existing Clojure
> literature you can provide functions to shuffle away the annoyance of
> dealing with keywords and their namespaces entirely.
>

[Jason Wolfe]

On Jan 19, 4:29 pm, Jason Wolfe <jawo...@berkeley.edu> wrote:
> I've been doing some OO-type Clojure programming, and have run into
> the following (quite minor) annoyance:
>
> I've defined a struct with a :class of ::Foo in namespace
> my.long.namespace.foo.
>
> In another namespace my.long.namespace.bar, I want to define a
> subclass of this struct.
> In this namespace, I require [...foo :as foo], so that I can refer to
> multimethods like foo/method1.
>
> However, it seems I'm still required to write
> (derive ::Bar :my.long.namespace.foo/Foo)
> when I'd like to write
> (derive ::Bar :foo/Foo)

On IRC, "duck1123" just showed me that this is already implemented;
you just have to use the "::" form.

(derive ::Bar ::foo/Foo)

You learn something new every day...

-Jason

[David Nolen]

Nice :)