On Nov 18, 2019, at 10:27, Random832 <random...@fastmail.com> wrote: > > On Mon, Nov 18, 2019, at 13:00, Andrew Barnert via Python-ideas wrote: >> def f(a, b): return a**(b+1) >> g = partial(f, b==2) >> h = lambda x: f(x, 2) >> >> Python can’t tell the difference between f, g, and h; they’re all >> variables. An IDE could keep track of the fact that f was bound by a >> def statement, and g and h by assignment. But I’m not sure why you’d >> want it to. After all, they’re all variables with callable values. Why >> should f(2,3) be colored differently from g(4)? > > I think, more or less, "a function" can be regarded as "a *constant* whose > value is callable and is not type-like" [where type-like includes types, > abstract base classes, and type hint objects], regardless of how it was > obtained.
Well, none of f, g, and h are immutable values, or constant names. But I take your point. An IDE that could actually understand all of these things as “functions” as distinct from other kinds of names, that would be pretty cool, if very difficult. Still, is it really the “probably not mutated or rebound” that’s the important distinction here, or just the “callable like a function” part? (Or maybe even “called like a function in this code”? I’m not sure what coloring you’d ideally want inside the body of higher-order functions, to be honest… Maybe the answer is to look at what highlighters for F#, Scala, or Haskell do, and whether anyone ever wishes for more?) While we’re at it, int is literally a type, and yet we normally think of int(s, base=16) as a function call rather than a type call. On second thought, maybe that “we” only includes people who’ve been using Python since 2.2 or longer… But the larger point that you can’t easily distinguish between types and functions is important to Python. When a function wants a “factory” you often just pass a type T rather than lambda *a, **kw: T(*a, **kw), but for less trivial cases you pass a function (or, for that matter, a classmethod intended to act as an alternate constructor). There are things in the stdlib that look like type constructors but aren’t. And so on. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@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/NEHSMDF46TPC43U2IRKNZPY3DCPWDKEQ/ Code of Conduct: http://python.org/psf/codeofconduct/
