New PEP: The directive statement

[Martin von Loewis]

hzhu at users.sourceforge.net (Huaiyu Zhu) writes:

> So with this directive PEP, the parallel would be
> 
> directive transitional nested_scope
> directive experimentatal stackless
> directive optional static_type
> directive mandatory string_methods
> 
> Is this correspondence correct?  (You may not agree on the need for other
> directives, but I want to know if the keyword translations are correct.)

That is a possible application. The syntax allows other choices as well,
e.g.

  directive static_type
  directive stackless 0

> 1. It introduces a new syntax while an existing syntax could be reused
>    without much cost.

You mean, import can be reused without much cost? The cost of reusing
import is quite high; it causes irritation among users.

> 2. There is no place for version and documentation info.

That is true.

> So far as I can see, the impetus for directive keyword is that import is a
> run time action, while the __future__ is a compile time declaration.  But is
> it so far a stretch?  All Python __magic__ words go beyond normal meaning.
> Defining __setattr__ will affect more than this method alone.  Having
> __init__.py will cause other modules to be imported.  And so on.

That is what I dislike in the __ convention. Syntactically, they are
identifiers. Semantically, they are reserved words.

> If we look more broadly, in *nix, devices, processes, pipe and others are
> also represented as files.  Would it better to assign special syntax to all
> of them?

Or, taking the analogy further: sockets should be represented as files
as well, to open a socket, you should really open some file, not
invoke a special function. Yet, history shows that the version with
the special API was the successful one, not the version with the files.

Generalization is a dangerous thing: you can too easily cross the
border to over-generalization.

> IMHO, reusing existing syntax is closer to Python than Perl, which
> introduces new syntax for many things that are only slightly different.

Are you saying that activating nested scopes is only slightly
different from importing modules?

Regards,
Martin