32.1 Abstract Grammar

-- ASDL's five builtin types are identifier, int, string, object, bool
module Python version "$Revision: 43614 $"
{
	mod = Module(stmt* body)
	 | Interactive(stmt* body)
	 | Expression(expr body)
	 -- not really an actual node but useful in Jython's typesystem.
	 | Suite(stmt* body)
	stmt = FunctionDef(identifier name, arguments args, 
 stmt* body, expr* decorators)
	 | ClassDef(identifier name, expr* bases, stmt* body)
	 | Return(expr? value)
	 | Delete(expr* targets)
	 | Assign(expr* targets, expr value)
	 | AugAssign(expr target, operator op, expr value)
	 -- not sure if bool is allowed, can always use int
 	 | Print(expr? dest, expr* values, bool nl)
	 -- use 'orelse' because else is a keyword in target languages
	 | For(expr target, expr iter, stmt* body, stmt* orelse)
	 | While(expr test, stmt* body, stmt* orelse)
	 | If(expr test, stmt* body, stmt* orelse)
	 | With(expr context_expr, expr? optional_vars, stmt* body)
	 -- 'type' is a bad name
	 | Raise(expr? type, expr? inst, expr? tback)
	 | TryExcept(stmt* body, excepthandler* handlers, stmt* orelse)
	 | TryFinally(stmt* body, stmt* finalbody)
	 | Assert(expr test, expr? msg)
	 | Import(alias* names)
	 | ImportFrom(identifier module, alias* names, int? level)
	 -- Doesn't capture requirement that locals must be
	 -- defined if globals is
	 -- still supports use as a function!
	 | Exec(expr body, expr? globals, expr? locals)
	 | Global(identifier* names)
	 | Expr(expr value)
	 | Pass | Break | Continue
	 -- XXX Jython will be different
	 -- col_offset is the byte offset in the utf8 string the parser uses
	 attributes (int lineno, int col_offset)
	 -- BoolOp() can use left & right?
	expr = BoolOp(boolop op, expr* values)
	 | BinOp(expr left, operator op, expr right)
	 | UnaryOp(unaryop op, expr operand)
	 | Lambda(arguments args, expr body)
	 | IfExp(expr test, expr body, expr orelse)
	 | Dict(expr* keys, expr* values)
	 | ListComp(expr elt, comprehension* generators)
	 | GeneratorExp(expr elt, comprehension* generators)
	 -- the grammar constrains where yield expressions can occur
	 | Yield(expr? value)
	 -- need sequences for compare to distinguish between
	 -- x < 4 < 3 and (x < 4) < 3
	 | Compare(expr left, cmpop* ops, expr* comparators)
	 | Call(expr func, expr* args, keyword* keywords,
			 expr? starargs, expr? kwargs)
	 | Repr(expr value)
	 | Num(object n) -- a number as a PyObject.
	 | Str(string s) -- need to specify raw, unicode, etc?
	 -- other literals? bools?
	 -- the following expression can appear in assignment context
	 | Attribute(expr value, identifier attr, expr_context ctx)
	 | Subscript(expr value, slice slice, expr_context ctx)
	 | Name(identifier id, expr_context ctx)
	 | List(expr* elts, expr_context ctx) 
	 | Tuple(expr *elts, expr_context ctx)
	 -- col_offset is the byte offset in the utf8 string the parser uses
	 attributes (int lineno, int col_offset)
	expr_context = Load | Store | Del | AugLoad | AugStore | Param
	slice = Ellipsis | Slice(expr? lower, expr? upper, expr? step) 
	 | ExtSlice(slice* dims) 
	 | Index(expr value) 
	boolop = And | Or 
	operator = Add | Sub | Mult | Div | Mod | Pow | LShift 
 | RShift | BitOr | BitXor | BitAnd | FloorDiv
	unaryop = Invert | Not | UAdd | USub
	cmpop = Eq | NotEq | Lt | LtE | Gt | GtE | Is | IsNot | In | NotIn
	comprehension = (expr target, expr iter, expr* ifs)
	-- not sure what to call the first argument for raise and except
	-- TODO(jhylton): Figure out if there is a better way to handle
	-- lineno and col_offset fields, particularly when
 -- ast is exposed to Python.
	excepthandler = (expr? type, expr? name, stmt* body, int lineno,
	 int col_offset)
	arguments = (expr* args, identifier? vararg, 
		 identifier? kwarg, expr* defaults)
 -- keyword arguments supplied to call
 keyword = (identifier arg, expr value)
 -- import name with optional 'as' alias.
 alias = (identifier name, identifier? asname)
}