32.2. ast — Abstract Syntax Trees — Python 2.7.18 documentation (original) (raw)

The module defines a string constant __version__ which is the decimal Subversion revision number of the file shown below.

-- ASDL's five builtin types are identifier, int, string, object, bool

module Python version "$Revision$" { 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)
      | ClassDef(identifier name, expr* bases, stmt* body, expr* decorator_list)
      | 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)
     | 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)
     -- 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
excepthandler = ExceptHandler(expr? type, expr? name, stmt* body)
                attributes (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)

}