from compiler import ast

### Simple tools used by the parser
#

# XXX: Remove in favor of the logging framework
def printdebug(msg):
    """
    """
    print 'parser: %s' % msg

def list_strip(seq):
    """
    Remove all None element from a list.
    """
    ret = []
    for item in seq:
        if item:
            ret.append(item)
    return ret

def list_flatten(seq):
    """
    Pulls up multi-level lists into a single level list.
    Example:
        [[a,b],c,[[d]]] -> [a,b,c,d]
    """
    ret = []
    for item in seq:
        if isinstance(item, list):
            ret += list_flatten(item)
        else:
            ret.append(item)
    return ret


### AST Functions
#
def ast_make_dict(seq):
    """
    Function that takes a sequence and returns
    an ast making a dictionnary.

    Example ASTs:
        {'a':1, 'b':2}
        Dict([(Const('a'), Const(1)), (Const('b'), Const(2))])
        
        dict(a=1,b=2)
        CallFunc(Name('dict'), [Keyword('a', Const(1)), Keyword('b', Const(2))], None, None)
        
        dict(d1,c=3)
        CallFunc(Name('dict'), [Name('d1')], None, Dict([(Const('c'), Const(3))]))
    """
    seq = list_strip(seq)
    if True in [isinstance(item, ast.Name) for item in seq]:
        # We have a Name in the seq, use the dict construtor.
        args = []
        name = []
        for item in seq:
            if isinstance(item, ast.Name):
                name.append(item)
            else:
                args.append(item)
        # print name, ast.Dict(args)
        ret = ast.CallFunc(ast.Name('dict'), name, None, ast.Dict(args))
    else:
        ret = ast.Dict(seq)
    # print seq, '->', ret
    return ret