[Python-ideas] Keyword declarations
steve at pearwood.info
Wed May 16 20:53:46 EDT 2018
On Wed, May 16, 2018 at 07:24:19PM +0200, Adam Bartoš wrote:
> I have yet another idea regarding the the clashes between new keywords and
> already used names. How about introducing two new keywords *wink* that
> would serve as lexical keyword/nonkeyword declarations, similarly to
> nonlocal and global declarations?
> def f():
> nonkeyword if
> if = 2 # we use 'if' as an identifier
> def g():
> keyword if
> if x > 0: pass # now 'if' again introduces a conditional statement
This is absolutely no help at all for the common case that we have an
identifier that is a keyword and want to use it as a keyword in the same
block. For example, we can currently write:
value = data.except_
value = data.missing()
say. We're using "except_" because the data comes from some external
interface where it uses "except", but we can't use that because its a
I also challenge to think about how you will document the complicated
rules for when you can and can't use keywords as names, especially think
about explaining them to beginners:
print(None) # What will this print?
x = None # Fine, but what does it do?
None = 999 # Is this an error or not?
Remember the KISS principle.
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