[Python-Dev] Early PEP draft (For Python 3000?) (original) (raw)

Eyal Lotem eyal.lotem at gmail.com
Tue Oct 11 23:31:42 CEST 2005

I would like to re-suggest a suggestion I have made in the past, but with a mild difference, and a narrower scope.

Name: Attribute access for all namespaces

Rationale: globals() access is conceptually the same as setting the module's attributes but uses a different idiom (access of the dict directly). Also, locals() returns a dict, which implies it can affect the local scope, but quietly ignores changes. Using attribute access to access the local/global namespaces just as that is used in instance namespaces and other modules' namespaces, could reduce the mental footprint of Python.

Method: All namespace accesses are attribute accesses, and not direct dict accesses. Thus globals() is replaced by a "module" keyword (or "magic variable"?) that evaluates to the module object. Thus, reading/writing globals in module X, uses getattr/setattr on the module object, just like doing so in module Y would be. locals() would return be replaced by a function that returns the frame object (or a weaker equivalent of a frame object) of the currently running function. This object will represent the local namespace and will allow attribute getting/setting to read/write attributes. Or it can disallow attribute setting.

Examples:

   global x ; x = 1

Replaced by: module.x = 1

or:

  globals()[x] = 1

Replaced by: setattr(module, x, 1)

  locals()['x'] = 1 # Quietly fails!

Replaced by: frame.x = 1 # Raises error

  x = locals()[varname]

Replaced by: x = getattr(frame, varname)

Advantages:

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