Recursive python "product"

product.py

"""
this has a lot of list / tuple casting, and doesn't use
native python list properties to full advantage.

It mimics Little Schemer style coding quite well though.
"""


import itertools

def produit(*lists):
    """  generator of full outer product over all lists
    
    >>> lists = [[1,2,3],[4,5],[6,7]]
    >>> a = list(produit(*lists))
    >>> b = list(itertools.product(*lists))
    >>> len(a), len(b)
    (12, 12)
    >>> sorted(a) == sorted(b)
    True
    """
    if lists:
        L, rest = lists[0],lists[1:]
        for x in L:
            for y in produit(*rest):
                yield tuple([x] + list(y))
    else:
        yield []
    
    """
    if len(lists) == 1:
        for x in lists[0]:
            yield [x,]
    else:
        for x in lists[0]:
            for y in produit(*lists[1:]):
                yield tuple([x] + list(y))
    """
                
            
"""
[1,2,3],[4,5,6],[7,8]



for each x in something([4,5,6],[7,8]):
    yield [1] + x
    
1 + something([4,5,6]
"""