pretty.py 文件源码

def _print_factorial(self, e):
        x = e.args[0]
        pform = self._print(x)
        # Add parentheses if needed
        if not ((x.is_Integer and x.is_nonnegative) or x.is_Symbol):
            pform = prettyForm(*pform.parens())
        pform = prettyForm(*pform.right('!'))
        return pform