Favorite non-python language trick?

[Joseph Garvin]

As someone who learned C first, when I came to Python everytime I read
about a new feature it was like, "Whoa! I can do that?!" Slicing, dir(),
getattr/setattr, the % operator, all of this was very different from C.

I'm curious -- what is everyone's favorite trick from a non-python
language? And -- why isn't it in Python?

Here's my current candidate:

So the other day I was looking at the language Lua. In Lua, you make a
line a comment with two dashes:

-- hey, this is a comment.

And you can do block comments with --[[ and ---]].

--[[
hey
this
is
a
big
comment
--]]

This syntax lets you do a nifty trick, where you can add or subtract a
third dash to change whether or not code runs:

--This code won't run because it's in a comment block
--[[
print(10)
--]]

--This code will, because the first two dashes make the rest a comment,
breaking the block
---[[
print(10)
--]]

So you can change whether or not code is commented out just by adding a
dash. This is much nicer than in C or Python having to get rid of """ or
/* and */. Of course, the IDE can compensate. But it's still neat :)

[NickC]

Steven D'Aprano wrote:

with colour do begin
red := 0; blue := 255; green := 0;
end;

instead of:

colour.red := 0; colour.blue := 255; colour.green := 0;

c = colour
c.red = 0; c.blue = 255; c.green = 0
del c # Not strictly needed, but limits the scope of c

When everything's a reference, the Pascal 'with' syntax doesn't gain
you anything over a single-letter variable name. As I recall, it's
handy in Pascal because record assignment has value semantics rather
than reference semantics.

Cheers,
Nick.

[Benji York]

Terry Hancock wrote:

http://www.logilab.org/projects/python-logic/ This is something pretty new to me, so I can't comment on how well
it would meet your expectations, but I see now that the site does mention
OZ/Mozart as comparables.

I've used both, the logilab stuff is cool, but no where near the
maturity (or speed) of OZ/Mozart. OTOH, I can actually get things
done with the logilab code. But that might say more about me than
Mozart. :)
--
Benji York

[todddeluca]

If I had to choose one feature, I would like to see better support for
nested lexical scopes. However, I imagine this is no easy "trick" to
add to the language.

I'm curious -- what is everyone's favorite trick from a non-python
language? And -- why isn't it in Python?

[Terry Reedy]

"Paddy" <pa*******@nets cape.net> wrote in message
news:11******** **************@ g47g2000cwa.goo glegroups.com.. .

Sadly, its not a solution that I'm after, but a particular toolkit that
can be used for solving that type of problem.

Presuming this is an anwer to my comment about generators... I was pointing
you more to the method used than the particular solutions. Whether your
constraint problems are similar enough, I have no idea.

Terry J. Reedy

[Terry Hancock]

On Thursday 30 June 2005 10:21 am, to********@gmai l.com wrote:

If I had to choose one feature, I would like to see better support for
nested lexical scopes. However, I imagine this is no easy "trick" to
add to the language.

Doesn't that already happen in versions 2.2+?

What exactly do you mean by "better" support for nested lexical
scopes? Can you give an example of something that doesn't work,
but should?

I'm just curious. The whole question of lexical scoping seemed
a bit esoteric to me at the time --- I think I must instinctively
avoid situations where it causes trouble. The most important
exception would have to be the behavior of lambda and locally-defined
functions --- I still expect them to know the variables in the defining
function's namespace. But I think that lexical scoping fixed this
so that they do, IIRC (I don't use them often, so I'm not so sure).

--
Terry Hancock ( hancock at anansispacework s.com )
Anansi Spaceworks http://www.anansispaceworks.com

[ncf]

Eh, just figured it'd be worth noting...map, filter, and reduce should
be possible with the extended list syntaxes. Well, filter I know is,
but hte others /should/ be possible.

filter(lambda: <<condition>> , <<seq>>)
[some_var for some_var in <<seq>> if <<condition>>]
Honestly, though, I hope they don't drop the map functions and such.
That's one of the stronger functions of the language (IMO).

-Wes

[ncf]

Hmm...I think it's time I do better justice to what I previously wrote.
http://www.artima.com/weblogs/viewpost.jsp?thread=98196

The above article was linked by Python's PEP...

[Erik Max Francis]

ncf wrote:

Eh, just figured it'd be worth noting...map, filter, and reduce should
be possible with the extended list syntaxes. Well, filter I know is,
but hte others /should/ be possible.

filter(lambda: <<condition>> , <<seq>>)
[some_var for some_var in <<seq>> if <<condition>>]

reduce isn't.

--
Erik Max Francis && ma*@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
Who needs a dream / Who needs ambition
-- The Russian, _Chess_

[ncf]

Sorry, I realized that shortly after my post =X

[Pekka Karjalainen]

In article <ma************ *************** ***********@pyt hon.org>, Joseph Garvin wrote:

I'm curious -- what is everyone's favorite trick from a non-python
language? And -- why isn't it in Python?

Being able to use my native language without a hitch when naming my
variables &c. Java allows that because it supports almost any Unicode
character in its identifiers. With Python I occasionally have to stop and
think: "I can't name it that. What's better?"

Not everyone always writes their programs in English. Once you get used
to Java's naming possibilities, it's plain annoying to go back, even if
it's just a couple of letters that're lacking in my case.

--
Pekka Karjalainen - Oulu, Finland