Re: Enhancing variable scope control
the string class, which has some annoying tight couplings to "string" and 'string')
What does that mean?
It sounds like you are complaining that the syntax for creating strings creates strings. Or possibly the other way around: that strings are created by string syntax. What did you expect?
Here's my understanding: You can't extend the string class to add new functionality. You can only subclass it. Because of this, "character-strings" cannot be suffixed with new functionality. For instance, you can write x='FOO'.lower() and x ends up being "foo"; That's a function of the actual str class. Buf if you subclass str as MyStr and create a MyStr object of "192.168.1.100", you cannot write... "192.168.1.100".TestDottedQuad() ...because "192.168.1.100" can only be an instance of str, not of MyStr. You have to run TestDottedQuad() either indirectly on a variable of type MyStr, or as a parameter to a function in a MyStr class object. The root problem is that you cannot extend a class. This is one of the limits that result. Which, yes, I find very annoying. So, some years ago, I wrote a simple precompiler that enables syntax that extends built-in classes -- without monkey patching Python. So you can create a virtual class extension, write x='192.168.1.100'.TestDottedQuad() or x="192.168.1.100".TestDottedQuad() in your input source to be precompiled, and it will work as it should in the resulting output source.
This is very, very deliberately a design goal of Python.
Ruby is a largely similar language that deliberately made the decision you
advocate here. It's a good language, but also one in which monkey patching
by imported modules creates a huge amount of chaos.
Most large Ruby projects have adopted code standards to explicitly prohibit
the behavior you want, because the dangers greatly outweigh the benefits...
After concrete experience using said feature.
I think Python made the right decision here.
On Thu, Dec 1, 2022, 4:18 PM Anony Mous
the string class, which has some annoying tight couplings to "string" and 'string')
What does that mean?
It sounds like you are complaining that the syntax for creating strings creates strings. Or possibly the other way around: that strings are created by string syntax. What did you expect?
Here's my understanding:
You can't extend the string class to add new functionality. You can only subclass it. Because of this, "character-strings" cannot be suffixed with new functionality.
For instance, you can write x='FOO'.lower() and x ends up being "foo"; That's a function of the actual str class.
Buf if you subclass str as MyStr and create a MyStr object of "192.168.1.100", you cannot write...
"192.168.1.100".TestDottedQuad()
...because "192.168.1.100" can only be an instance of str, not of MyStr. You have to run TestDottedQuad() either indirectly on a variable of type MyStr, or as a parameter to a function in a MyStr class object.
The root problem is that you cannot extend a class. This is one of the limits that result. Which, yes, I find very annoying.
So, some years ago, I wrote a simple precompiler that enables syntax that extends built-in classes -- without monkey patching Python. So you can create a virtual class extension, write x='192.168.1.100'.TestDottedQuad() or x="192.168.1.100".TestDottedQuad() in your input source to be precompiled, and it will work as it should in the resulting output source. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-leave@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/4V36LW... Code of Conduct: http://python.org/psf/codeofconduct/
participants (2)
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Anony Mous -
David Mertz, Ph.D.