[Python-ideas] Yet another idea for assignment expressions

[Ken Hilton]

Hi all,

I've been following the discussion of assignment expressions and what the
syntax for them should be for awhile. The ones that seem to crop up most
are the original spelling, :=, the "as" keyword (and variants including
it), and the recently "local" pseudo-function idea.

I have another idea for a spelling of assignment expressions, mostly
inspired by real sentence structure. In a review I was writing recently, I
referred to CGI, Computer Generated Imagery. As a way of introducing the
full term and its abbreviation, I said "Computer Generated Imagery (CGI)".
That got me thinking: why not have something similar in Python? Obviously
simple parentheses ("expr(name)") definitely wouldn't work, that's a
function call. Similarly, brackets ("expr[name]") would be interpreted as
subscription. So why not use curly brackets, "expr{name}"? That doesn't
conflict with anything (currently it's a syntax error), and could be
documented appropriately.

Going back to the regex example, this is how it would look in that case:

    if re.match(exp, string){m}:
        print(m.group(0))

I am currently unsure how it would affect scope. I think it should be
effectively equivalent to a regular assignment statement (and hence follow
identical scope rules), i.e. the above example would be equivalent to the
following in all ways except syntax:

    m = re.match(exp, string):
    if m:
        print(m.group(0))

Thoughts? Please do let me know if there's some critical flaw with this
idea that I missed (or tell me if it's an amazing idea ;)), and just give
feedback, I guess.

Sincerely,
Ken;
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