abuse of lambda question

[Ben Wolfson]

On Wed, 07 Jun 2000 03:49:31 GMT, Ben Wolfson <rumjuggler at cryptarchy.org>
wrote:
[stuff]

Ok, I got it working now.  The complete lambdabuse.py file, so far, is:

"""
Functions to aid in grossly abusing lambdas.  This will greatly help Python
develop as a langauge.
For example, if you wanted to get every other element of a list in two
different lists, you *could*
write something nice and clear, like:
def everyother(list):
	evens, odds= [],[]
	putineven = 1
	for e in list:
		if putineven:
			evens.append(e)
			putineven = 0
		else:
			odds.append(e)
			putineven = 1
	return evens, odds

which can be called as everyother(range(20)), or you could write something
completely unreadable,
like:
everyother = lambda l, evens, odds, app=lambda a,e: lambda
a=a,e=e:a.append(e): Compose(Apply(map, lambda e, evens=list(evens),
odds=list(odds), l=l,app=app: If(l.index(e)%2==0, app(evens,e),
app(odds,e)), l), Return(None, evens, odds))

which *must* be called as everyother(range(20),[],[]).
The choice is obvious.
"""

def For(count, fct, *args, **kwargs):
	for i in range(count):
		fct(i,*args,**kwargs)

def While(cond, fct, *args, **kwargs):
	while cond():
		fct(*args, **kwargs)

def Compose(*args):
	for f in args[:-1]:
		f()
	return args[-1]()

def Return(index, *args):
	if index is not None:
		return lambda a=args[index]: a
	return lambda a=args:a
	

def Apply(f, *args, **kwargs):
	return lambda f=f, a=args, k=kwargs: apply(f,a,k)

def If(cond, t, f):
	if callable(cond):
		cond = cond()
	if cond:
		return t()
	return f()

__everyother = lambda l, evens, odds, app=lambda a,e:\
  lambda a=a,e=e:a.append(e): Compose(
    Apply(map, \
      lambda e, evens=list(evens), odds=list(odds), l=l,app=app: \
        If(l.index(e)%2==0, app(evens,e), app(odds,e)), l),\
    Return(None, evens, odds))


def Elif(cond, t, f, *cond_elifs):
	conditions, eliffuncs = __everyother(list(cond_elifs),[],[])
                                     #must be a list to use .index()
	if callable(cond):
		cond=cond()
	if cond:
		return t()
	else:
		for i in range(len(conditions)):
			if conditions[i]():
				return eliffuncs[i]()
	return f()

def Map(f, *args):
	return lambda f=f, args=args: map(f, *args)

def Print(a):
	def p(a=a):
		print a
	return p

##an example.  For a group of lists l1...ln, 
##__unmapNone(map(None, l1,...,ln)) == (l1,...,ln)

__unmapNone=lambda l, result: Compose(
  Apply(For, len(l), lambda c, a: a.append([]), result),
  Map(lambda a,r=result: For(len(a), \
    lambda c,a,r: r[c].append(a[c]), a, r),l),
  Return(0,result))

-- 
Barnabas T. Rumjuggler

So witless did these ideas strike me as being, so sweeping and pompous the
way they were expressed, that I associated them immediately with
literature.
 -- Jorge Luis Borges, "The Aleph"