[Python-3000] PEP: rename it.next() to it.next(), add a next() built-in (original) (raw)

Collin Winter collinw at gmail.com
Tue Mar 6 18:43:26 CET 2007

On 3/5/07, Collin Winter <collinw at gmail.com> wrote:

On 3/5/07, Ka-Ping Yee <python-dev at zesty.ca> wrote: [snip] > Transition Plan > =============== > > Two additional transformations will be added to the 2to3 translation > tool [2]: > > * Method definitions named next will be renamed to _next_. > > * Explicit calls to the next method will be replaced with calls > to the built-in next function. For example, x.next() will > become next(x). > > If the module being processed already contains a top-level function > definition named next, the second transformation will not be done; > instead, calls to x.next() will be replaced with x._next_() > and a warning will be emitted.

The basic transformations for this are (relatively) easy to implement. Basing the second transformation on the absence of a top-level function definition (don't forget assignments and imports!) for "next", though, is going to require some surgery to 2to3's internals. I'll see what I can do.

Preliminary results:

After playing around with 2to3 for a while, it doesn't seem possible to base the second transformation on the presence of a top-level "next" binding. I can detect the binding's presence and warn about it, but just not in time to impact the "it.next()" -> "next(it)" transformation. I'm tinkering with an implementation that defers the transformation until 2to3 has finished walking the entire tree, but it's a lot of clutter and hackery for something like this.

Collin Winter

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