32.2. ast — Abstract Syntax Trees — Python 3.4.10 documentation (original) (raw)

-- ASDL's six builtin types are identifier, int, string, bytes, object, singleton

module Python { 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* decorator_list, expr? returns)
      | ClassDef(identifier name, 
         expr* bases,
         keyword* keywords,
         expr? starargs,
         expr? kwargs,
         stmt* body,
         expr* decorator_list)
      | Return(expr? value)

      | Delete(expr* targets)
      | Assign(expr* targets, expr value)
      | AugAssign(expr target, operator op, expr value)

      -- 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(withitem* items, stmt* body)

      | Raise(expr? exc, expr? cause)
      | Try(stmt* body, excepthandler* handlers, stmt* orelse, stmt* finalbody)
      | Assert(expr test, expr? msg)

      | Import(alias* names)
      | ImportFrom(identifier? module, alias* names, int? level)

      | Global(identifier* names)
      | Nonlocal(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)
     | Set(expr* elts)
     | ListComp(expr elt, comprehension* generators)
     | SetComp(expr elt, comprehension* generators)
     | DictComp(expr key, expr value, comprehension* generators)
     | GeneratorExp(expr elt, comprehension* generators)
     -- the grammar constrains where yield expressions can occur
     | Yield(expr? value)
     | YieldFrom(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)
     | Num(object n) -- a number as a PyObject.
     | Str(string s) -- need to specify raw, unicode, etc?
     | Bytes(bytes s)
     | NameConstant(singleton value)
     | Ellipsis

     -- the following expression can appear in assignment context
     | Attribute(expr value, identifier attr, expr_context ctx)
     | Subscript(expr value, slice slice, expr_context ctx)
     | Starred(expr value, 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 = 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)

excepthandler = ExceptHandler(expr? type, identifier? name, stmt* body)
                attributes (int lineno, int col_offset)

arguments = (arg* args, arg? vararg, arg* kwonlyargs, expr* kw_defaults,
             arg? kwarg, expr* defaults)

arg = (identifier arg, expr? annotation)
       attributes (int lineno, int col_offset)

-- keyword arguments supplied to call
keyword = (identifier arg, expr value)

-- import name with optional 'as' alias.
alias = (identifier name, identifier? asname)

withitem = (expr context_expr, expr? optional_vars)

}