Re: Tcl/Lisp/Python: A "User" point of view
Jeff Dalton (jeff@aiai.ed.ac.uk)
Thu, 29 Sep 1994 19:47:04 GMT
In article <BOBO.94Sep27093605@avogadro.arc.nasa.gov> bobo@ptolemy.arc.nasa.gov writes:
>I was recently surfing through the net and saw that among the new
>features of the language Python was support for functional
>programming. I clicked and saw the following:
>
> Lambda Forms
> ============
>
> By popular demand, a few features commonly found in functional
> programming languages and Lisp have been added to Python. With the
> lambda keyword, small anonymous functions can be created. Here's a
> function that returns the sum of its two arguments:
>
> lambda a, b: a+b.
>
> Lambda forms can be used wherever function objects are
> required. They are syntactically restricted to a single
> expression. Semantically, they are just syntactic sugar for a
> normal function definition. Like nested function definitions,
> lambda forms cannot reference variables from the containing scope,
> but this can be overcome through the judicious use of default
> argument values, e.g.
>
>
> def make_incrementor(n):
> return lambda(x, incr=n): x+incr
Can someone who knows Python explain what this does / how it works?
My guess is that the value of n is textually substituted for "n" in
"return lambda(x, incr=n): x+incr". But I know nothing of Python.
-- jeff