python fold tasks

folds.py

def flen(lst):
    return reduce(lambda acc, x: acc + 1, lst, 0)

def flpos(lst, item):
    def f(acc, x):
        found, pos = acc
        if found != -1:
            return acc
        if x == item:
            return pos, pos
        else:
            return -1, pos + 1
    res, _ = reduce(f, lst, (-1, 0))
    return res

def frpos(lst, item):
    def f(acc, x):
        found, pos = acc
        if x == item:
            return pos, pos + 1
        else:
            return found, pos + 1
    res, _ = reduce(f, lst, (-1, 0))
    return res

def fmap(lst, fun):
    def f(acc, x):
        acc.append(fun(x))
        return acc
    return reduce(f, lst, [])