Expresso 是一款 .NET 环境下的正则表达式编写与测试工具。当你编写正则表达式时，它将给你提供极大的帮助，并且它是免费（但需要注册）。
这个工具在codeproject上有详细介绍，出品时间也比The Regulator早。The Regulator的作者也受到了Expresso
的影响，才开发的The Regulator。他在The Regulator的帮助文件中说："The Original idea
for The Regulator came from a simple Regex Tester called "Expresso". It
was simple and easy to use (to a certain degree), but it mainly prompted the
idea in me that I could build something similar with features that I wished I
had.
So thanks, Expresso. Couldn't have done this one without ya! "
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