R. David Murray added the comment: The docstring discussion is correct in the context. property can easily be used to create a read only property because when used as a decorator the function that follows the decorator call is passed to it as fget, *and it copies the docstring from the function into the created property*. The 'then' is indeed redundant (if kept should properly be set of by commas, but there is no reason to keep it). 'turns the voltage' is still part of the previous sentence. Read it as "create read-only properties easily using property() as a decorator as follows...[this example] turns the voltage() method into a..." Your reformulation is, however, clearer. The comma in the 'fget is a function' sentence is in the correct place. "and fdel a function for del'ing" is phrase...I forget the formal name for the type of phrase. It's analogous to the structure of this sentence: "She forgot to bring not only her lunch, but also her wallet, to work". However, the comma after 'value' should technically be a semicolon. Although correct, I think the whole sentence would read better if it instead said "fget is a function for getting an attribute value, fset is a function for setting an attribute value, and fdel is a function for del'ing an attribute." ---------- nosy: +r.david.murray _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue22174> _______________________________________

diana added the comment: This whitespace? Or did you mean something else? class C: def __init__(self): self._x = None def getx(self): return self._x def setx(self, value): self._x = value def delx(self): del self._x x = property(getx, setx, delx, "I'm the 'x' property.") versus: class C: def __init__(self): self._x = None def getx(self): return self._x def setx(self, value): self._x = value def delx(self): del self._x x = property(getx, setx, delx, "I'm the 'x' property.") I added it to be consistent with the rest of the code snippets in the property docs. For example: class C: def __init__(self): self._x = None @property def x(self): """I'm the 'x' property.""" return self._x @x.setter def x(self, value): self._x = value @x.deleter def x(self): del self._x Of the three code snippets in the property docs, that first one is the only one that doesn't have whitespace between the methods. That first code snippet also has inconsistent whitespace within itself (__init__ vs the rest of methods). Anyhoo, that was my reasoning, but that's largely beside the point. I will happily drop it and leave it as-is. What really prompted me to submit a patch was this paragraph: "If given, doc will be the docstring of the property attribute. Otherwise, the property will copy fget‘s docstring (if it exists). This makes it possible to create read-only properties easily using property() as a decorator:" I now understand the original intent, but I don't think it's clear as-is. I also find it a bit odd that 'fget', 'fset', 'fdel' are all defined in the first sentence of the docs, but 'doc' isn't. It then launches into an example that uses 'doc' (still as of yet undefined), before defining 'doc' later on in the read-only properties part. I'll think on it a bit some more -- feel free to close this in the mean time. It's been this way for a better part of a decade, so perhaps it's just me ;) Cheers, --diana ---------- _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue22174> _______________________________________

Raymond Hettinger added the comment: Most of the patch looks to be an improvement. I've massaged it a little and attached a revised patch. ---------- Added file: http://bugs.python.org/file36332/property2.diff _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue22174> _______________________________________

Roundup Robot added the comment: New changeset 98a2e215ff01 by Raymond Hettinger in branch '2.7': Issue #22174: Clean-up grammar and ambiguities in property() docs. http://hg.python.org/cpython/rev/98a2e215ff01 ---------- _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue22174> _______________________________________