[Python-Dev] Document performance requirements? (original) (raw)

Armin Rigo arigo at tunes.org
Sat Jul 22 13:19:07 CEST 2006

Hi,

On Sat, Jul 22, 2006 at 12:33:45PM +1000, Nick Coghlan wrote:

Agreed, but there's more to doing that than just writing down the O() implied by the current CPython implementation - it's up to Guido to decide which of the constraints are part of the language definition, and which are implementation accidents

I think that O-wise the current CPython situation should be documented as a "minimal requirement" for implementations of the language, with just one exception: the well-documented "don't rely on this" hack in 2.4 to make repeated 'str += str' amortized linear, for which the 2.3 quadratic behavior is considered compliant enough.

I suppose that allowing implementations to provide better algorithmic complexities than required is fine, although I can think of some problems with that (e.g. nice and efficient user code that would perform horribly badly on CPython).

Armin

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