Clojurescript - Javascript constructor and namespace with the same name problem

[Marko Kocić]

Hi all,

When dealing with ClojureScript and Closure library it happens pretty often that Closure namespace is in the same time constructor for some object.

Take a look for this example:

(ns notepad

  (:require 

     [goog.dom :as dom]

     [goog.ui.Zippy :as Zippy]))

First, require forces me to require goog.ui.Zippy as Zippy and later in the code I have to use fully qualified name instead of provided one.

This works

(goog.ui.Zippy. headerElement contentElement)

This doesn't work, since Zippy is namespace declaration

(Zippy. headerElement contentElement)

I know that we can't have both namespace and function with the same name, but this is pretty frequent situation in Closure library, and is a bit awkward.

One solution would be that namespace :as symbol is specialcased so that without namespace prefix Zippy and Zippy. works like a regular function, and when in place of namespace prefix, it works as a namespace prefix. That would be pretty in line with Closure library itselfi.

Then we would be able to use

(require [goog.ui.Zippy :as Zippy])

(def z (Zippy. "ttt" "sss")) ;; same as calls goog.ui.Zippy.

(Zippy/someMethod x) ;; same as goog.ui.Zippy

What would be your proposal for this?

[Chris Granger]

FWIW, one work around for this is to include the sub-namespace as well
and reference it from that one. So in your example:

(ns notepad
(:require
[goog.dom :as dom]

[goog.ui :as ui]
[goog.ui.Zippy :as Zippy]))

(ui/Zippy. "ttt" "sss")

[David Nolen]

This is an known existing issue. Using :require to important constructors just doesn't make sense.

2 patches I think could help here:

1) support for :import

2) support for :require w/o :as

Anyone game to submit some fixes?

David

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[tomoj]

I noticed that it works fine to just do (:require [goog.async.Deferred :as d]) and to use (goog.async.Deferred.) to call the constructor (in this case Deferred is also used as a namespace, so require makes sense).

With :require w/o :as support, you'd have (:require goog.async.Deferred) ... (goog.async.Deferred.), right?

So with :import, (:import goog.async.Deferred) ... (Deferred.)? I would have expected (:import goog.async.Deferred.CancelledError) to cause trouble here, but in this case at least, deferred.js also provides goog.async.Deferred.CancelledError.

David

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[David Nolen]

On Mon, Jun 11, 2012 at 1:37 PM, tomoj <t...@tomoj.la> wrote:

I noticed that it works fine to just do (:require [goog.async.Deferred :as d]) and to use (goog.async.Deferred.) to call the constructor (in this case Deferred is also used as a namespace, so require makes sense).

With :require w/o :as support, you'd have (:require goog.async.Deferred) ... (goog.async.Deferred.), right?

Yes.

 

So with :import, (:import goog.async.Deferred) ... (Deferred.)? I would have expected (:import goog.async.Deferred.CancelledError) to cause trouble here, but in this case at least, deferred.js also provides goog.async.Deferred.CancelledError.

I think the following should work:

(:import goog.async.Deferred)

(:import [goog.async Deferred ...])

Other thoughts?

David

[Michał Marczyk]

On 11 June 2012 18:49, David Nolen <dnolen...@gmail.com> wrote:
> Anyone game to submit some fixes?

I am. I'll create a new ticket for :import and build :require w/o :as
on top of that (attaching patch to CLJS-272).

M.

[Michał Marczyk]

See

http://dev.clojure.org/jira/browse/CLJS-312

for :import (patch attached). Looking at 272 now...

[David Nolen]

Thanks!

[Michał Marczyk]

Patch attached to 272 (note it's created on top of 312).

Cheers,
M.

[David Nolen]

:require now no longer requires :as. :require now also supports :refer (thanks Michal!) which brings us in line with Clojure on the JVM. Still discussing the implications of doing :import (CLJS-312).

David