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Clarify "late binding" in gotchas #267

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Apr 4, 2013
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Clarify "late binding" in gotchas #267

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7 changes: 4 additions & 3 deletions docs/writing/gotchas.rst
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Expand Up @@ -128,11 +128,12 @@ What Does Happen

Five functions are created, but all of them just multiply ``x`` by 4.

Python's closures are *late binding*. This means that names within closures are
looked up at the time the inner function is *called*.
Python's closures are *late binding*.
This means that the values of variables used in closures are looked
up at the time the inner function is called.

Here, whenever *any* of the returned functions are called, the value of ``i``
is looked up in the surrounding scope at call time, when by then the loop has
is looked up in the surrounding scope at call time. By then, the loop has
completed and ``i`` is left with its final value of 4.

What's particularly nasty about this gotcha is the seemingly prevalent
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