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Revise the description of when functions retrieved from class instances

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are and are not turned into bound methods; some confusion was noted by
Andrew Dalke.

In particular, it has to be noted that functions located on the class
instance are not turned into any sort of method, only those which are
found via the underlying class.
This commit is contained in:
Fred Drake 2000-06-28 20:15:47 +00:00
parent 6da0b9148c
commit 35c09f2e51
1 changed files with 11 additions and 9 deletions
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20
Doc/ref/ref3.tex
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@ -438,11 +438,12 @@ base class of the class of which \member{im_self} is an instance);
User-defined method objects are created in two ways: when getting an
attribute of a class that is a user-defined function object, or when
getting an attributes of a class instance that is a user-defined
function object. In the former case (class attribute), the
\member{im_self} attribute is \code{None}, and the method object is said
to be unbound; in the latter case (instance attribute), \method{im_self}
is the instance, and the method object is said to be bound. For
getting an attribute of a class instance that is a user-defined
function object defined by the class of the instance. In the former
case (class attribute), the \member{im_self} attribute is \code{None},
and the method object is said to be unbound; in the latter case
(instance attribute), \method{im_self} is the instance, and the method
object is said to be bound. For
instance, when \class{C} is a class which contains a definition for a
function \method{f()}, \code{C.f} does not yield the function object
\code{f}; rather, it yields an unbound method object \code{m} where
@ -452,9 +453,7 @@ instance, \code{x.f} yields a bound method object \code{m} where
\code{m.im_class} is \code{C}, \code{m.im_func} is \method{f()}, and
\code{m.im_self} is \code{x}.
\withsubitem{(method attribute)}{
\ttindex{im_class}
\ttindex{im_func}
\ttindex{im_self}}
\ttindex{im_class}\ttindex{im_func}\ttindex{im_self}}
When an unbound user-defined method object is called, the underlying
function (\member{im_func}) is called, with the restriction that the
@ -474,7 +473,10 @@ the class or instance. In some cases, a fruitful optimization is to
assign the attribute to a local variable and call that local variable.
Also notice that this transformation only happens for user-defined
functions; other callable objects (and all non-callable objects) are
retrieved without transformation.
retrieved without transformation. It is also important to note that
user-defined functions which are attributes of a class instance are
not converted to bound methods; this \emph{only} happens when the
function is an attribute of the class.
\item[Built-in functions]
A built-in function object is a wrapper around a \C{} function. Examples