2016-03-11 6:38 GMT+01:00, Franklin? Lee leewangzhong+python@gmail.com:
On Mar 10, 2016 10:51 PM, "Nick Coghlan" ncoghlan@gmail.com wrote:
[...]
It's also worth reading PEP 343 for Guido's explanation for why the context management assignment syntax isn't "with VAR = EXPR": it's because EXPR *isn't* the thing being assigned, but rather a stepping stone towards obtaining that thing. This characteristic is true of all of the places where "as" is currently used instead of "=":
[...]
Then would it be a problem if it defaulted to the value of EXPR directly when that value isn't of a specially-handled type (such as a context manager, for `with`)? Other than that learning `with` in comprehensions might make it harder to learn context managers.
Or we could think about syntax "with VAR = EXPR" where it is plain assignment.
If we wanted in PEP343 (and still we want) to have different syntax for different semantics then it is better, I think.
PS. from my point of view I still don't see why is "with" so much better than existing syntax "for VAR in [EXPR]"
for example why is this not enough? ->
import unicodedata [(c, i, cat, name, norm) for i in range(1, 0x110000) for c in [chr(i)] for cat in [unicodedata.category(chr(i))] for name in [unicodedata.name(chr(i), 'noname')] for uname in [name.upper()] # name is defined in previous row for norm in [unicodedata.normalize('NFKC', chr(i))] if 'OPERATOR' in uname if norm != c ]
PPS. if we want to change syntax the "for VAR = EXPR" is also possibility