ast_translator.py 文件源码

def _translate_unaryop(self, operand, op, location):
        value = operand
        if isinstance(op, ast.USub):
            value_node = self._translate_node(value)
            if value_node['pseudo_type'] != 'Int' and value_node['pseudo_type'] != 'Float':
                raise type_check_error('- expects Int or Float',
                    location, self.lines[location[0]],
                    wrong_type=value_node['pseudo_type'])
            if value_node['type'] == 'int':
                return {
                    'type': 'int',
                    'value': -value_node['value'],
                    'pseudo_type': 'Int'
                }
            else:
                return {
                    'type': 'unary_op',
                    'op': '-',
                    'value': value_node,
                    'pseudo_type': value_node['pseudo_type']
                }
        elif isinstance(op, ast.Not):
            value_node = self._testable(self._translate_node(value))
            if value_node['type'] == 'standard_method_call' and value_node['message'] == 'present?':
                value_node['message'] = 'empty?'
                return value_node
            else:
                return {
                    'type': 'unary_op',
                    'op': 'not',
                    'value': value_node,
                    'pseudo_type': 'Boolean'
                }
        else:
            raise translation_error('no support for %s as an unary op' % type(op).__name__,
                location, self.lines[location[0]],
                suggestions='not and - are supported')