On 09/19/2012 09:25 AM, Deryck Hodge wrote: > On Wed, Sep 19, 2012 at 5:37 AM, Gavin Panella > <gavin.pane...@canonical.com> wrote: >> On 18 September 2012 18:51, Richard Harding <rick.hard...@canonical.com> >> wrote: >> ... >>> var ns = Y.lp.registry.product.view; >> >> Why is doing this not enough? It seems that getting rid of nested >> namespaces is a fairly big piece of work in order to avoid best >> practice as above, i.e. simulating `from module import thing`. > > It's not just the assignment or lookup alone; there's also the > performance hit for creating that namespace. Also, that assignment > hit has to be paid over and over in each test. Every JavaScript book > will note that nested properties are slow in every browser. We've > just been lazy about this. Now we have definitive proof that it costs > us something -- i.e. Rick had a test that failed due to a timeout > error, due to these long namespaces. So it makes sense to fix it now, > or at least not make it worse going forward.
This is also another case where our lucid test runner is using a much older version of webkit then was shipped Maverick! [1] As Deryck says, identifier and member resolution is expensive. The webkit we used on Maverick and beyond is about 20x faster at resolving scopes and members than lucid. [1] Purple stopped-the-line 6 months ago because we had genuine defects in JavaScript that modern webkit gracefully corrected for us, but old browsers would topple. -- Curtis Hovey http://launchpad.net/~sinzui
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