[Python-ideas] Inline Functions - idea

[Steven D'Aprano]

On Wed, Feb 05, 2014 at 06:47:35PM -0800, Guido van Rossum wrote:
> On Wed, Feb 5, 2014 at 4:53 PM, Ethan Furman <ethan at stoneleaf.us> wrote:

> > class MyString(str):
> >   def find(sub, start, end):
> >     ...
> >     # manipulate sub and/or start and/or end
> >     ...
> >     return super().find(#blah#)
> >
> > where #blah# means "pick out sub, start, and end from locals and use them".
> >
> 
> And how on earth would the compiler know the argument names?

This is not a defence of the idea, which I find rather nasty, but I 
suppose you might compile the call x.find(#blah#) into code like this:

# pseudo-code
func = getattr(x, 'find')
arg_list = inspect.getargspec(func).args
l = locals()
args = {arg: l[arg] for arg in arg_list if arg != "self"}
func(**args)

I think this idea would be inefficient, hard to understand, and brittle, 
just to save the programmer from having to explicitly write out the 
arguments to a function. I'm sure it would be really popular in PHP 
circles :-)


-- 
Steven