import ast
import inspect

FUNC_NAME = "__lambda__"

def λ(*args):
    prev_frame = inspect.currentframe().f_back

    body = ast.parse(args[-1], "<lambda>", "exec").body
    args = args[:-1]

    def make_arg(a):
        a = ast.arg(a, None, None)
        a.lineno = 0
        a.col_offset = 0
        return a

    arguments = ast.arguments(posonlyargs=[],
                              args=[make_arg(a) for a in args],
                              kwonlyargs=[], kw_defaults=[], defaults=[])
    arguments.lineno = 0
    arguments.col_offset = 0
    func = ast.FunctionDef(FUNC_NAME, arguments, body, [])
    func.lineno = 0
    func.col_offset = 0
    toplevel = ast.Interactive([func])
    toplevel.lineno = 0
    toplevel.col_offset = 0
    func = compile(toplevel, "<lambda>", "single")

    exec(func, prev_frame.f_globals, prev_frame.f_locals)
    func = prev_frame.f_locals[FUNC_NAME]
    del prev_frame.f_locals[FUNC_NAME]

    return func


# Examples:
#
# λ("""print("haha multiline lambdas")
# return 1337""")()
#
# --------------------------------------
#
# λ("a", "b", "c", """if a:
#     return b
# else:
#     return c""")(False, 1, 2)
#
# --------------------------------------
#
# meow = 10
# λ("a", "b", "c", """if a:
#     return b + meow
# else:
#     return c + meow""")(False, 1, 2)
#
# --------------------------------------
#
# def my_func():
#     meow = 20
#     return λ("cnd", """if cnd:
#     return meow
# else:
#     return 'nope'""")
#
# meow = 30
# my_func()(True)
#
# --------------------------------------
#
# def my_func():
#     meow = 20
#     return λ("cnd", """global meow
# if cnd:
#     return meow
# else:
#     return 'nope'""")
#
# meow = 30
# my_func()(True)
#