[Python-ideas] Method chaining notation

[Masklinn]

On 2014-02-21, at 23:00 , spir <denis.spir at gmail.com> wrote:
> Also, I don't find the idea of having a builtin construct for such hacks a good idea. Libs for which this may be practicle can return self --end of the story.

That has two issues though:

1. it makes chainability a decision of the library author, the library
   user gets to have no preference. This means e.g. you can't create
   a tree of elements in ElementTree in a single expression (AFAIK
   Element does not take children parameters). With cascading, the
   user can "chain" a library whose author did not choose to support
   chaining (in fact with cascading no author would ever need to
   support chaining again).

2. where a return value can make sense (and be useful) the author
   *must* make a choice. No way to chain `dict.pop()` since it
   returns the popped value, even if `pop` was only used for its
   removal-with-shut-up properties. With cascading the user can
   have his cake and eat it: he gets the return value if he
   wants it, and can keep "chaining" if he does not care.