import dyngram, parser

newrules = """
compound_stmt: if_stmt | on_stmt | unless_stmt | dountil_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef
dountil_stmt: 'do' ':' suite 'until' test
unless_stmt: 'unless' test ':' suite
on_stmt: 'on' NAME '=' test ':' suite ['else' ':' suite]
"""

def build_dountil_stmt(items):
    """ 'do' ':' suite 'until' ':' test """
    lineno = items[0].lineno
    suite = items[2]
    test = items[-1]
    while_stmt = parser.ASTWhile(parser.ASTNot(test), suite, None, lineno)
    return parser.ASTStmt([suite, while_stmt], lineno)

def build_unless_stmt(its):
    """ 'unless' test ':' suite  """
    lineno = its[0].lineno
    return parser.ASTIf([(parser.ASTNot(its[1]), its[3])], None, lineno)

def make_assignment(var, node):
    # XXX: consts.OP_APPLY
    return parser.ASTAssign([parser.ASTAssName('x', 0)], node)

def build_on_stmt(items):
    """ 'on' NAME = test ':' suite  'else' ':' suite"""
    varname = items[1].value
    test = items[3]
    suite = items[5]
    assign = make_assignment(varname, test)
    if len(items) == 9:
        else_ = items[-1]
    else:
        else_ = None
    test = parser.ASTIf([(parser.ASTName(varname), suite)], else_, items[0].lineno)
    return parser.ASTStmt([assign, test], items[0].lineno)

dyngram.insert_grammar_rule(newrules, {'dountil_stmt' : build_dountil_stmt,
                                       'unless_stmt': build_unless_stmt,
                                       'on_stmt' : build_on_stmt,
                                       })