Hence, if text matched the entire pattern, the first set of parentheses would yield a string representing a positive or negative integer, such as + 49.
因此，如果文本匹配了整个模式，第一组括号将生成表示一个正整数或负整数的的字符串，例如+ 49。
2
This has been dubbed "sterilised" QE or "Operation twist", after a 1960s programme in which the Treasury and the Fed tried to "twist" the yield curve by altering the pattern of Treasury-bond issuance.
While design patterns such the Participant pattern can yield a similar effect without actually requiring metadata support, they are somewhat abstruse to use.