tools.py 文件源码

def _new_constant(node, value):
    if isinstance(value, ast.AST):
        # convenient shortcut: return the AST object unchanged
        return value

    # FIXME: test the config directly here?

    if value is None:
        new_node = ast.Constant(value=None)
    elif isinstance(value, (bool, int, float, complex, str, bytes)):
        new_node = ast.Constant(value=value)
    elif isinstance(value, (tuple, frozenset)):
        if not _is_constant(value):
            raise TypeError("container items are not constant: %r" % (value,))
        new_node = ast.Constant(value=value)
    elif isinstance(value, list):
        elts = [_new_constant(node, elt) for elt in value]
        new_node = ast.List(elts=elts, ctx=ast.Load())
    elif isinstance(value, dict):
        keys = []
        values = []
        for key, value in value.items():
            keys.append(_new_constant(node, key))
            values.append(_new_constant(node, value))
        new_node = ast.Dict(keys=keys, values=values, ctx=ast.Load())
    elif isinstance(value, set):
        elts = [_new_constant(node, elt) for elt in value]
        new_node = ast.Set(elts=elts, ctx=ast.Load())
    else:
        raise TypeError("unknown type: %s" % type(value).__name__)

    copy_lineno(node, new_node)
    return new_node


# FIXME: use functools.singledispatch?