On Tue, Jun 09, 2020 at 05:06:37PM -0700, Guido van Rossum wrote:
> But wait, there's more! The same syntax will make it possible to call *any*
> function:
>
> >>> len "abc"
> 3
As you point out later on, there are issues with zero-argument calls and
calls where the first argument starts with parens.
Ruby allows parens-less function calls. Run this in Ruby and weep:
#!/usr/bin/ruby
def a(x=4)
x+2
end
b = 1
print "a + b => ", (a + b), "\n"
print "a+b => ", (a+b), "\n"
print "a+ b => ", (a+ b), "\n"
print "a +b => ", (a +b), "\n"
For those who don't have Ruby installed, here is the output:
a + b => 7
a+b => 7
a+ b => 7
a +b => 3
In case it's not obvious, the problem isn't the call to print, but the
call to function `a`. (Tested in Ruby 2.5).
There's also yet another precedence rule to learn:
sqrt x + 1
means what?
Given Python's execution model where we have statements and functions, I
think that it is a feature that they have different syntax. If I see
words separated by spaces:
import math
del spam
while condition
if obj
assert condition
I know that they are special syntactic forms, even if I'm reading code
using some new statement I had missed learning about:
# Python 7 code, fallen through a wormhole
require thing
demand permission
spam contacts
verb object
I don't think we should give up that nice clean distinction between
function calls which always require parens, and statements which don't
require parens, merely to add a second way to call functions that saves
one char:
func(x)
func x
I'd be more interested in the idea if there was more benefit than just
the avoidance of a pair of parens. Something that either can't be done
at all, or can only be done with difficulty. Something like IPython's
%magic syntax perhaps?
--
Steven
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