On Thu, Jan 27, 2011 at 7:27 AM, David Herman <dher...@mozilla.com> wrote: > We thought for a while about > demand-driven evaluation of modules. There are a couple reasons why I > believe it would be too problematic. First, we'd really like to make the act > of throwing your code into a module as transparent as possible; changing the > control flow would make modules more heavyweight. But more importantly, > since as you mentioned, module evaluation can contain arbitrary side > effects, evaluating them lazily means laziness with side effects. This makes > for really hard-to-understand and hard-to-debug initialization errors, where > you end up having to write mysterious top-level imports to force evaluation > of modules in particular orders. Laziness + side-effects: bad scene, man.
On the opposite side of the argument, I presume that this means that modules are evaluated when their transitive dependencies are loaded. This would imply that the order in which the modules are delivered, possibly over a network using multiple connections, would determine the execution order, which would in turn be non-deterministic. Non-determinisim + side-effects is also a bad scene. Is there an alternate method proposed in Simple Modules for deterministically linearizing the evaluation order? Non-determinism is definitely a greater evil than providing developers a means to explicate the order in which they would like their side-effects to be wrought. Kris Kowal _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
