Does Python really follow its philosophy of "Readability counts"?
tjreedy at udel.edu
Wed Jan 21 04:41:57 CET 2009
Duncan Booth wrote:
> Luis Zarrabeitia <kyrie at uh.cu> wrote:
>> It boggles me when I see python code with properties that only set and
>> get the attribute, or even worse, getters and setters for that
>> purpose. In my university they teach the students to write properties
>> for the attributes in C# ("never make a public attribute, always write
>> a public property that just gets and sets it"). I never understood
>> that practice either, given that the syntax for attribute access and
>> property access in C# is exactly the same. (Could it be that even if
>> the syntax is the same, the compiled code differs? Don't know enough
>> about .NET to answer that).
> The compiled code differs.
I *strongly* doubt that. Properties are designed to be transparent to
user code that access atrributes through the usual dotted name notation
precisely so that class code can be changed from
x = ob
x = property(get_x, set_x, del_x)
without changing user code.
CPython compiles attribute access to
The code associated with LOAD_ATTR should get the attribute object and
check whether it is a property, in which case it calls the proper method
of the property.
> That doesn't matter if the class is only
> accessed from within a single compiled program, but it does matter if you
> expose a public interface from a library: if you change a public attribute
> into a property then you need to recompile all code which accesses it.
Example to back this claim? Perhaps you have found a bug.
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