Hello all,
I would like to briefly share my thoughts on non-standard evaluation (NSE),
why this is useful, and how, potentially, it can be added to Python. In
most languages, functions have access only to the *value* of their
arguments, and not to the expressions that yielded those values. Howeve
On Jul 13, 2019, at 12:16, Nima Hamidi wrote:
>
>
> In the following, I sketch how I think this can be implemented:
> Let BoundExpression be a class containing an ast.Expression as well as locals
> and globals dictionaries. BoundExpression can also have an eval method that
> evaluates its expr
Serhiy Storchaka wrote:
> Are your aware of contextlib.nested()? And why it was deprecated and
> removed?
Was contextlib.nested() removed primarily due to to the inconsistencies
mentioned in https://bugs.python.org/issue5251 or was it something else?
_
Thank you very much for your reply!
I wasn't familiar with MacroPy. It's a good idea to implement NSE using it.
I'll work on it.
Sometimes it's necessary not to evaluate the expression. Two such applications
of NSE in R are as follows:
1. Data-tables have cleaner syntax. For example, letting d
It's an interesting idea, and has come up occasionally before. It probably
stems from Lisp, where it's common practice (IIRC control flow like 'if' is
defined this way). I believe it's called quoting there -- I've never heard
the term NSE before. (Is that term specific to R?)
I'm glad you start ou
(Re-sending, because this was originally a reply to an off-list message by Nima
Hamidi)
On Jul 13, 2019, at 14:12, Nima Hamidi wrote:
>
> Sometimes it's necessary not to evaluate the expression. Two such
> applications of NSE in R are as follows:
>
> 1. Data-tables have cleaner syntax. For
Delaying evaluation in some way looks like a useful feature which was up to
this point integrated to python only by introducing special syntax
for each problem which appeared. Out of my mind:
the "conditional if trueresult else falseresult" appeared because one can't
write something like if(conditi
