Mats Wichmann: [Idle-dev] Use of __future__ features in IDLE

[Tim Peters]

> Do you recall what this was?

A limitation documented in PEP 236 (the __future__ PEP).

Michael Hudson and I repaired it for Python 2.2, via PEP 264 ("Future
statements in simulated shells").  The fixes are too involved to backstitch
into 2.1.x without significant effort, and nobody volunteered.

Even in 2.2, it's *easier* in IDLE to deal with a __future__ statement by
sticking one at the top of an IDLE file window, and using Execute Script
repeatedly as the file changes.  Nested scopes in particular require writing
non-trivial code to have visible effect, and typing non-trivial code "live"
at an interactive prompt is often a regrettable idea.