Flex (Fast Lexical Analyzer Generator) is a developer tool used for creating "scanners"—programs that recognize complex patterns in text. Version remains a popular legacy release, particularly for Windows developers and computer science students learning compiler design. Where to Download Flex 2.5.4a
You can download the pre-compiled installer flex-2.5.4a-1.exe from the GnuWin32 SourceForge page . download flex 2.5.4a