From 6acdbc3db543f2692ee336a99722f5ab0b46c77e Mon Sep 17 00:00:00 2001 From: Walter Bender Date: Wed, 13 Nov 2013 22:42:18 +0000 Subject: convert to new primitive type --- (limited to 'TurtleArt/tatype.py') diff --git a/TurtleArt/tatype.py b/TurtleArt/tatype.py new file mode 100644 index 0000000..3ca47b9 --- /dev/null +++ b/TurtleArt/tatype.py @@ -0,0 +1,443 @@ +#Copyright (c) 2013 Marion Zepf + +#Permission is hereby granted, free of charge, to any person obtaining a copy +#of this software and associated documentation files (the "Software"), to deal +#in the Software without restriction, including without limitation the rights +#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +#copies of the Software, and to permit persons to whom the Software is +#furnished to do so, subject to the following conditions: + +#The above copyright notice and this permission notice shall be included in +#all copies or substantial portions of the Software. + +#THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +#THE SOFTWARE. + +""" type system for Primitives and their arguments """ + +import ast + +from tablock import Media +from taconstants import (Color, CONSTANTS) + + +class Type(object): + """ A type in the type hierarchy. """ + + def __init__(self, constant_name, value): + """ constant_name -- the name of the constant that points to this Type + object + value -- an arbitrary integer that is different from the values of + all other Types. The order of the integers doesn't matter. """ + self.constant_name = constant_name + self.value = value + + def __eq__(self, other): + if other is None: + return False + if not isinstance(other, Type): + return False + return self.value == other.value + + def __str__(self): + return str(self.constant_name) + __repr__ = __str__ + + +class TypeDisjunction(tuple,Type): + """ Disjunction of two or more Types (from the type hierarchy) """ + + def __init__(self, iterable): + self = tuple(iterable) + + def __str__(self): + s = ["("] + for disj in self: + s.append(str(disj)) + s.append(" or ") + s.pop() + s.append(")") + return "".join(s) + + +# individual types +TYPE_OBJECT = Type('TYPE_OBJECT', 0) +TYPE_BOOL = Type('TYPE_BOOL', 5) +TYPE_BOX = Type('TYPE_BOX', 8) # special type for the unknown content of a box +TYPE_CHAR = Type('TYPE_CHAR', 1) +TYPE_COLOR = Type('TYPE_COLOR', 2) +TYPE_FLOAT = Type('TYPE_FLOAT', 3) +TYPE_INT = Type('TYPE_INT', 4) +TYPE_MEDIA = Type('TYPE_MEDIA', 10) +TYPE_NUMBER = Type('TYPE_NUMBER', 6) # shortcut to avoid a TypeDisjunction + # between TYPE_FLOAT and TYPE_INT +TYPE_NUMERIC_STRING = Type('TYPE_NUMERIC_STRING', 7) +TYPE_STRING = Type('TYPE_STRING', 9) + +# groups/ classes of types +TYPES_NUMERIC = (TYPE_FLOAT, TYPE_INT, TYPE_NUMBER) + + +BOX_AST = ast.Name(id='BOX', ctx=ast.Load) +ACTION_AST = ast.Name(id='ACTION', ctx=ast.Load) + + +def get_type(x): + """ Return the most specific type in the type hierarchy that applies to x + and a boolean indicating whether x is an AST. If the type cannot be + determined, return TYPE_OBJECT as the type. """ + # non-AST types + if isinstance(x, (int, long)): + return (TYPE_INT, False) + elif isinstance(x, float): + return (TYPE_FLOAT, False) + elif isinstance(x, basestring): + if len(x) == 1: + return (TYPE_CHAR, False) + try: + float(x) + except ValueError: + return (TYPE_STRING, False) + else: + return (TYPE_NUMERIC_STRING, False) + elif isinstance(x, Color): + return (TYPE_COLOR, False) + elif isinstance(x, Media): + return (TYPE_MEDIA, False) + elif hasattr(x, "return_type"): + return (x.return_type, False) + + # AST types + elif isinstance(x, ast.Num): + return (get_type(x.n)[0], True) + elif isinstance(x, ast.Str): + return (get_type(x.s)[0], True) + elif isinstance(x, ast.Name): + try: + # we need to have imported CONSTANTS for this to work + value = eval(x.id) + except NameError: + return (TYPE_OBJECT, True) + else: + return (get_type(value)[0], True) + elif isinstance(x, ast.Subscript): + if x.value == BOX_AST: + return (TYPE_BOX, True) + elif isinstance(x, ast.Call): + if isinstance(x.func, ast.Name): + if x.func.id == 'float': + return (TYPE_FLOAT, True) + elif x.func.id in ('int', 'ord'): + return (TYPE_INT, True) + elif x.func.id == 'chr': + return (TYPE_CHAR, True) + elif x.func.id in ('repr', 'str', 'unicode'): + return (TYPE_STRING, True) + elif x.func.id == 'Color': + return (TYPE_COLOR, True) + elif x.func.id == 'Media': + return (TYPE_MEDIA, True) + # unary operands never change the type of their argument + elif isinstance(x, ast.UnaryOp): + if issubclass(x.op, ast.Not): + # 'not' always returns a boolean + return (TYPE_BOOL, True) + else: + return get_type(x.operand) + # boolean and comparison operators always return a boolean + if isinstance(x, (ast.BoolOp, ast.Compare)): + return (TYPE_BOOL, True) + # other binary operators + elif isinstance(x, ast.BinOp): + type_left = get_type(x.left)[0] + type_right = get_type(x.right)[0] + if type_left == TYPE_STRING or type_right == TYPE_STRING: + return (TYPE_STRING, True) + if type_left == type_right == TYPE_INT: + return (TYPE_INT, True) + else: + return (TYPE_FLOAT, True) + + return (TYPE_OBJECT, isinstance(x, ast.AST)) + + +def is_instancemethod(method): + # TODO how to access the type `instancemethod` directly? + return type(method).__name__ == "instancemethod" + +def is_bound_method(method): + return ((is_instancemethod(method) and method.im_self is not None) or + (hasattr(method, '__self__') and method.__self__ is not None)) + +def is_staticmethod(method): + # TODO how to access the type `staticmethod` directly? + return type(method).__name__ == "staticmethod" + + +def identity(x): + return x + +TYPE_CONVERTERS = { + # Type hierarchy: If there is a converter A -> B, then A is a subtype of B. + # The converter from A to B is stored under TYPE_CONVERTERS[A][B]. + # The relation describing the type hierarchy must be transitive, i.e. + # converting A -> C must yield the same result as converting A -> B -> C. + # TYPE_OBJECT is the supertype of everything. + TYPE_BOX: { + TYPE_FLOAT: float, + TYPE_INT: int, + TYPE_NUMBER: float, + TYPE_STRING: str}, + TYPE_CHAR: { + TYPE_INT: ord, + TYPE_STRING: identity}, + TYPE_COLOR: { + TYPE_FLOAT: float, + TYPE_INT: int, + TYPE_NUMBER: int, + TYPE_STRING: Color.get_number_string}, + TYPE_FLOAT: { + TYPE_INT: int, + TYPE_NUMBER: identity, + TYPE_STRING: str}, + TYPE_INT: { + TYPE_FLOAT: float, + TYPE_NUMBER: identity, + TYPE_STRING: str}, + TYPE_NUMBER: { + TYPE_FLOAT: float, + TYPE_INT: int, + TYPE_STRING: str}, + TYPE_NUMERIC_STRING: { + TYPE_FLOAT: float, + TYPE_STRING: identity} +} + + +class TATypeError(BaseException): + """ TypeError with the types from the hierarchy, not with Python types """ + + def __init__(self, bad_value, bad_type=None, req_type=None, message=''): + """ bad_value -- the mis-typed value that caused the error + bad_type -- the type of the bad_value + req_type -- the type that the value was expected to have + message -- short statement about the cause of the error. It is + not shown to the user, but may appear in debugging output. """ + self.bad_value = bad_value + self.bad_type = bad_type + self.req_type = req_type + self.message = message + + def __str__(self): + msg = [] + if self.message: + msg.append(self.message) + msg.append(" (") + msg.append("bad value: ") + msg.append(repr(self.bad_value)) + if self.bad_type is not None: + msg.append(", bad type: ") + msg.append(repr(self.bad_type)) + if self.req_type is not None: + msg.append(", req type: ") + msg.append(repr(self.req_type)) + if self.message: + msg.append(")") + return "".join(msg) + __repr__ = __str__ + + +def get_converter(old_type, new_type): + """ If there is a converter old_type -> new_type, return it. Else return + None. If a chain of converters is necessary, return it as a tuple or + list (starting with the innermost, first-to-apply converter). """ + # every type can be converted to TYPE_OBJECT + if new_type == TYPE_OBJECT: + return identity + # every type can be converted to itself + if old_type == new_type: + return identity + + # is there a converter for this pair of types? + converters_from_old = TYPE_CONVERTERS.get(old_type) + if converters_from_old is None: + return None + converter = converters_from_old.get(new_type) + if converter is not None: + return converter + else: + # form the transitive closure of all types that old_type can be + # converted to, and look for new_type there + backtrace = converters_from_old.copy() + new_backtrace = backtrace.copy() + break_all = False + while True: + newest_backtrace = {} + for t in new_backtrace: + for new_t in TYPE_CONVERTERS.get(t, {}): + if new_t not in backtrace: + newest_backtrace[new_t] = t + backtrace[new_t] = t + if new_t == new_type: + break_all = True + break + if break_all: + break + if break_all or not newest_backtrace: + break + new_backtrace = newest_backtrace + # use the backtrace to find the path from old_type to new_type + if new_type in backtrace: + converter_chain = [] + t = new_type + while t in backtrace and isinstance(backtrace[t], Type): + converter_chain.insert(0, TYPE_CONVERTERS[backtrace[t]][t]) + t = backtrace[t] + converter_chain.insert(0, TYPE_CONVERTERS[old_type][t]) + return converter_chain + return None + + +def convert(x, new_type, old_type=None, converter=None): + """ Convert x to the new type if possible. + old_type -- the type of x. If not given, it is computed. """ + if not isinstance(new_type, Type): + raise ValueError('%s is not a type in the type hierarchy' + % (repr(new_type))) + # every type can be converted to TYPE_OBJECT + if new_type == TYPE_OBJECT: + return x + if not isinstance(old_type, Type): + (old_type, is_an_ast) = get_type(x) + else: + is_an_ast = isinstance(x, ast.AST) + # every type can be converted to itself + if old_type == new_type: + return x + + # special case: 'box' block (or 'pop' block) as an AST + if is_an_ast and old_type == TYPE_BOX: + new_type_ast = ast.Name(id=new_type.constant_name) + return get_call_ast('convert', [x, new_type_ast], return_type=new_type) + + # if the converter is not given, try to find one + if converter is None: + converter = get_converter(old_type, new_type) + if converter is None: + # no converter available + raise TATypeError(bad_value=x, bad_type=old_type, + req_type=new_type, message=("found no converter" + " for this type combination")) + + def _apply_converter(converter, y): + try: + if is_an_ast: + if converter == identity: + return y + elif is_instancemethod(converter): + func = ast.Attribute(value=y, + attr=converter.im_func.__name__, + ctx=ast.Load) + return get_call_ast(func) + else: + func_name = converter.__name__ + return get_call_ast(func_name, [y]) + else: + return converter(y) + except BaseException: + raise TATypeError(bad_value=x, bad_type=old_type, + req_type=new_type, message=("error during " + "conversion")) + + if isinstance(converter, (list, tuple)): + # apply the converter chain recursively + result = x + for conv in converter: + result = _apply_converter(conv, result) + return result + elif converter is not None: + return _apply_converter(converter, x) + + +class TypedAST(ast.AST): + + @property + def return_type(self): + if self._return_type is None: + return get_type(self.func)[0] + else: + return self._return_type + + +class TypedCall(ast.Call,TypedAST): + """ Like a Call AST, but with a return type """ + + def __init__(self, func, args=None, keywords=None, starargs=None, + kwargs=None, return_type=None): + + if args is None: + args = [] + if keywords is None: + keywords = [] + + ast.Call.__init__(self, func=func, args=args, keywords=keywords, + starargs=starargs, kwargs=kwargs) + + self._return_type = return_type + + +class TypedSubscript(ast.Subscript,TypedAST): + """ Like a Subscript AST, but with a type """ + + def __init__(self, value, slice_, ctx=ast.Load, return_type=None): + + ast.Subscript.__init__(self, value=value, slice=slice_, ctx=ctx) + + self._return_type = return_type + + +class TypedName(ast.Name,TypedAST): + """ Like a Name AST, but with a type """ + + def __init__(self, id_, ctx=ast.Load, return_type=None): + + ast.Name.__init__(self, id=id_, ctx=ctx) + + self._return_type = return_type + + +def get_call_ast(func_name, args=None, kwargs=None, return_type=None): + """ Return an AST representing the call to a function with the name + func_name, passing it the arguments args (given as a list) and the + keyword arguments kwargs (given as a dictionary). + func_name -- either the name of a callable as a string, or an AST + representing a callable expression + return_type -- if this is not None, return a TypedCall object with this + return type instead """ + if args is None: + args = [] + # convert keyword argument dict to a list of (key, value) pairs + keywords = [] + if kwargs is not None: + for (key, value) in kwargs.iteritems(): + keywords.append(ast.keyword(arg=key, value=value)) + # get or generate the AST representing the callable + if isinstance(func_name, ast.AST): + func_ast = func_name + else: + func_ast = ast.Name(id=func_name, ctx=ast.Load) + # if no return type is given, return a simple Call AST + if return_type is None: + return ast.Call(func=func_ast, args=args, keywords=keywords, + starargs=None, kwargs=None) + # if a return type is given, return a TypedCall AST + else: + return TypedCall(func=func_ast, args=args, keywords=keywords, + return_type=return_type) + + -- cgit v0.9.1