SEAR for Mac

From From Concentrate Software:

There are a lot of different ways to store and transmit text. Lots of systems use lots of different methods, some suited better for the web, some better suited only for use with certain applications. A specific format, setext, can be read and understood easily without the help of software, but it can look a lot better. SEAR reads setext documents and displays them beautifully using custom styles. SEAR also makes writing setext easy, providing a standard editor (that anyone familiar with TextEdit can use) and options to save and copy text (into setext, HTML, or rtf).

• Styles setext for easy reading
• Imports and exports setext, HTML, and rtf
• Applescript support