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[CLJS-335] user defined tagged literals in CLJS Created: 06/Jul/12  Updated: 10/Nov/15  Resolved: 10/Nov/15

Status: Closed
Project: ClojureScript
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Minor
Reporter: kovas boguta Assignee: Unassigned
Resolution: Completed Votes: 1
Labels: None


I'm trying to make my own tagged literals for cljs, and its a rough scene. I've probably spend 15 hours trying to get this to work properly.

The quick hack of binding cljs-data-readers is a pretty bad solution, and doesn't work with cljsbuild.

One solution is to just copy the mechanism of data_readers.clj, instead calling it cljs_data_readers.clj. That would help.

A better solution is to just pass through all the tagged literals, and resolve them on the cljs side, eg `((cljs.core/get (cljs.core/deref cljs.reader/tag-table) ~tag) ~data))

That way the definition of the tags doesn't have to be repeated twice, as is done now (once in cljs.reader, and once in the clj-side cljs.tagged-literals) .

The problem with this is that clj itself is incapable of passing through undefined tags without exploding, which is also a near showstopper. Having something like cljs_data_readers.clj would get the job done in the meantime.

(another minor issue is that the cljs reader doesn't handle namespaced symbols, so in #a/b, b is what is used as the key into cljs-data-readers)

Comment by kovas boguta [ 06/Jul/12 12:52 AM ]

I've never used this before, so just assume everything in bold has earmuffs around it.

Comment by David Nolen [ 30/Aug/12 7:38 PM ]

This seems like a lot of separate issues rolled into one. Can we break this ticket apart into simpler actionable tickets?

Comment by kovas boguta [ 15/Dec/12 10:35 PM ]

Now that we have default-data-reader-fn, its possible to have a clean fix. Just set default-data-reader-fn to the function described above.

Should I generate a patch?

Comment by David Nolen [ 21/Dec/12 4:58 PM ]

What function defined above?

Comment by kovas boguta [ 25/Dec/12 1:30 PM ]

the function is
(fn [tag data] `((cljs.core/get (cljs.core/deref cljs.reader/tag-table) ~tag) ~data))

The proposal is to bind default-data-reader-fn to the above, in compiler.clj for the compile-file* function. And get rid of the binding for data-readers in that function as well.

It should be possible to get rid of the tagged_literals.clj file as well, since those definitions are no longer needed after this change.

Comment by David Nolen [ 12/Mar/14 8:31 AM ]

Is this still an issue today?

Comment by David Nolen [ 10/Nov/15 10:14 AM ]

In a post conditional reading world we have a real solution to this problem.

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