Ideas for Python 3

[David MacQuigg]

On Wed, 28 Apr 2004 02:22:55 +0200, Michael Walter <cm at leetspeak.org>
wrote:

>David MacQuigg wrote:
> > [...]
>> It took me a long time to realize that lamdas have only one advantage
>> over named functions - they can be crammed into a tight space.  Here
>> is an example:
>> 
>> L = [(lambda x: x**2), (lambda x:x**3), (lambda x:x**4), (lambda
>> x:x**5)]
>> 
>> If the purpose is to save space, wouldn't this be better as:
>> 
>> L = [:x:x**2, :x:x**3, :x:x**4 :x:x**5]
>   L = map(lambda x: lambda y: x**y,range(2,6))
>
>Almost. Or write mapc ("map currying") and have:
>
>   L = mapc(pow,range(2,6))
>
>Shorter than your example, less mistake-prone, no obvious lambda at all ;)

The problem with this suggestion ( and many other similar uses of
existing functions ) is that it relies on a regular mathematical
sequence.  Think of a more general case, something like:

L = [:x:x**2, :x:x+4, :x:x/5, :x:2-x, :x:x*7 ]

I would like to get some feedback on the more general questions:

Q1) Is it worth having a "lambda" syntax like this, or should we just
deprecate lambda functions entirely and use:

def f1(x): return x**2
def f2(x): return x+4
def f3(x): return x/5
def f4(x): return 2-x
def f5(x): return x*7
L = [ f1, f2, f3, f4, f5 ]

Q2) Will it help new users to have the "lambda" syntax be as close as
possible to a normal function definition?  i.e.

f :(x): return x**2  # a simple function
:x:x**2              # equivalent lambda expression

-- or --

f = def(x): return x**2
def x:x**2

I am especially interested in feedback from users who have recently
learned Python.  I suspect that many experienced users will have long
forgotten any difficulties they had while learning.

-- Dave