Comments on: Managing namespaces

By: Namespaces in Clojure are confusing | Smash Company

Namespaces in Clojure are confusing | Smash Company — Mon, 10 Sep 2012 19:57:59 +0000

[...] So far I have enjoyed working with Clojure, but I still get confused by name spaces, for the reasons… One aspect of Clojure that I have not been quite happy with is namespace management. In a bigger project that consists of several namespaces, I usually end up having nearly identical :use and :require clauses in the initial ns form. These clauses set up the project-specific set of symbols that I want to work with. Individual namespaces sometimes add symbols for their specific needs, of course. What bothers me is that I have to repeat the :use and :require clauses, often with :exclude or nly options with many symbols, in every single namespace. And of course I often forget a copy when updating my symbol set. Therefore I decided to look at how namespaces work in more detail, and try to find a better way to manage symbols in namespaces. [...]

By: Martin

Martin — Sat, 11 Sep 2010 16:03:47 +0000

This was a really useful post when trying to make sense of namespaces!

By: khinsen

khinsen — Thu, 18 Feb 2010 10:43:05 +0000

There’s already remove-ns. Combine this with in-ns, and you get the equivalent of emptying a namespace, except that the namespace object changes, rendering aliases invalid.

But… what would you use this for in practice? The only namespace I ever wanted to reset is “user”, from the REPL. But it’s just as easy to make a new one instead.

By: khinsen

khinsen — Thu, 18 Feb 2010 10:38:51 +0000

If modifying the behaviour of the compiler is an option, then it would be sufficient to allow redefining a symbol that currently points to a var in another namespace.

I am not sure if that’s a good idea though. At least at the REPL level, I like the error message that prevents me from overwriting something accidentally. Perhaps the default behaviour should differ between the REPL and loading from a file.

By: Stuart Halloway

Stuart Halloway — Thu, 18 Feb 2010 08:48:07 +0000

I created a ticket for this: http://www.assembla.com/spaces/clojure/tickets/272-load-ns-require-use-overhaul and will bring it up on the dev list.

By: Alex Miller

Alex Miller — Thu, 18 Feb 2010 06:04:34 +0000

Seriously awesome explanation of namespaces…many thanks.

By: Nicolas Buduroi

Nicolas Buduroi — Thu, 18 Feb 2010 00:10:23 +0000

Just remembered something else, what would be great is a function to reset/empty a namespace.

By: Nicolas Buduroi

Nicolas Buduroi — Wed, 17 Feb 2010 21:49:16 +0000

Great post! I’ve had some problems with this myself and wrote some helpers, but didn’t had the time to push thing that far.

> simply add all symbols defined in your namespace to the :remove list.

This could be automated with a function that you would call at the end of your namespace. If integrate into Clojure this could also be done automatically by the compiler, with warnings to let you know.

By: Phil

Phil — Wed, 17 Feb 2010 18:19:58 +0000

This is really interesting; I’ve had the same complaints with copy/pasting of huge blocks of use clauses all around a project. I know there’s been talk of a huge overhaul of the ns macro for a future release; I wonder if :like or something similar could make it into that. http://www.mail-archive.com/clojure@googlegroups.com/msg20403.html