> None if var:= function() is None else var.method() Make sense.
In some specific scenes(maybe general, I'm not sure), var.method() if var:=function() else var looks cool although it's not really null checking. It works for Python, just like use `if lst` to check if the list `lst` is empty. 2018-04-13 11:22 GMT+08:00 David Mertz <me...@gnosis.cx>: > Yes, I should have added ternary expressions to if statements. I can > definitely see the use there. > > However, your example is not null checking. You'd have to modify it > slightly to get that: > > None if var:= function() is None else var.method() > > Still not bad looking. > > On Thu, Apr 12, 2018, 11:01 PM Thautwarm Zhao <yaoxiansa...@gmail.com> > wrote: > >> >> > You're looking at a very early commit there. I suggest looking at the >> > most recent commits on one of two branches: >> >> https://github.com/Rosuav/cpython/blob/statement-local- >> variables/Grammar/Grammar >> https://github.com/Rosuav/cpython/blob/assignment- >> expressions/Grammar/Grammar >> >> > Those are the two most recent states in my progress towards (a) >> > statement-local name bindings with "EXPR as NAME", and (b) assignment >> > expressions with "target := value". >> >> Okay, and the syntax "target := value" seems to be much easier to handle >> with. >> >> I do support this feature, but now I'm worried about the meaning of ':=', >> it seems to be a lazy assignment in some degree. I'm not sure using ':=' is >> proper here. >> >> >> > Inasmuch as I might like assignment expressions, it would only be in >> while or if statements, personally. >> >> Not exactly, assignment expression also works for "if expression", we can >> now have null checking. >> >> var.method() if var:= function() else None >> >> Null checking is importance enough to have a specific syntax in many >> other languages(C#, kotlin, Ruby and so on), and we can even have more than >> null checking by adding expression assignment. >> >> >> >> >> _______________________________________________ >> Python-ideas mailing list >> Python-ideas@python.org >> https://mail.python.org/mailman/listinfo/python-ideas >> Code of Conduct: http://python.org/psf/codeofconduct/ >> >
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