C#, .Net, JSON, XML, Async Method and system for automating the editing of computer files. Computer users may commonly perform some repetitive or patterned actions while editing text files such as scripts, or editing markup files like HTML or XML, or editing source code or even regular text files that contain tabular data or lists. The program determines a pattern transformation, then applies it to any part of the text that matches a "Pattern". The method thus develops an algorithm that makes the transformation from "Pattern 1" to "Pattern 2", and formalizes it, by developing a finite-state machine. The pattern transformation is applied to any part of the text that matches "Pattern 1", and after this transformation has been applied, then the new text will match the user's intentions