[Python-ideas] The pipe protocol, a convention for extensible method chaining

[M.-A. Lemburg]

On 26.05.2015 01:38, Stephan Hoyer wrote:
> In the PyData community, we really like method chaining for data analysis
> pipelines:
> 
> (iris.query('SepalLength > 5')
>  .assign(SepalRatio = lambda x: x.SepalWidth / x.SepalLength,
>          PetalRatio = lambda x: x.PetalWidth / x.PetalLength)
>  .plot(kind='scatter', x='SepalRatio', y='PetalRatio'))

FWIW: I don't think this is a programming style we should encourage
in Python in general, so I'm -1 on this.

It doesn't read well, you cannot easily tell what the intermediate
objects are on which you run the methods, debugging the above becomes
hard, it only gives you a minor typing advantage over using variables
and calling methods on those and it gives you no performance
advantage.

If you need a pipe pattern, it would be better to make that
explicit through some special helper function or perhaps a
piping object on which you register the various steps to run.

-- 
Marc-Andre Lemburg
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