> So, I'm confused. I'm not sure what is allowed and under what circumstances, > and I'm not sure what I should be validating here. Zach very reasonably > argued that Clojure clearly permits this since Manifold works, but I'm not > sure if this is just a happy accident. Looking at the clojure.core code, it > seems that there is only circular dependency checking when using load, not > when using require.
I took a look at what’s going on in the manifold case. I’m not sure this explanation is enough to yield a solution to the problem you’re trying to solve, but it should be a good start. The cyclic load dependency check fails if `load` is asked to load a file while that same file has started loading but not yet finished loading. It’s a runtime check. `require` calls `load` conditionally to implement its basic function: “load a lib if it isn’t already loaded”. `require`’s processing of a given libspec may or may not result in a call to `load`: If the lib is already loaded, it isn’t loaded again. As of commit f11e70726553685bda222ccd37c28addcfc519c7 (29 November 2012, first in clojure-1.5.0-beta2), a lib is considered loaded as soon as an ns form for the corresponding namespace has been successfully evaluated. In the case of manifold.stream, the explicit calls to `require` occur after (ns manifold.stream …). Since manifold.stream is already considered loaded at that point, the indirect calls to (require ‘manifold.stream) that they generate do not result in calls to `load` and therefore do not trigger the cyclic load dependency check. —Steve -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
