Read-only attribute in module
tjreedy at udel.edu
Thu Feb 9 14:15:45 EST 2012
On 2/9/2012 6:43 AM, Mateusz Loskot wrote:
> I'm implementing Python 3 extension using the Python C API. I am
> familiar with defining new types, implementing get/set for
> attributes, etc.
> I'm wondering, is there any mean to implement attribute in module
> scope which is read-only?
Not that I know of. Python intentionally leaves modules mutable even
after the code has executed so they can be monkey-patched from outside.
The argument for is that it is unusual to do so but sometimes very
useful and necessary. The main argument against is that it prevents
optimizations that would make code in modules run faster.
> import xyz print(xyz.flag) # OK
> xyz.flag = 0 # error due to no write access
Why prevent that? If you called it 'FLAG', that would indicate that it
is a constant that should not be changed. While Python make some effort
to prevent bugs, it is generally a 'consenting adults' language.
Terry Jan Reedy
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