The OPML Editor is an outliner, an editor that works with chunks of text that slide around on rails. You can control the level of detail you look at, and reorganize according to structure.
This outliner works with very obvious indentation process to provide intuitive outlines that can be expanded or collapsed as needed. As seen in the image on the right the arrows, called wedges, show the expansion. They can be used to control collapsing and rearranging the info.
This is a free program.
The commands include:
|Control-U||Cmd-U||Move a line up at the same level|
|Control-D||Cmd-D||Move a line down at the same level|
|Control-R||Cmd-R||Move a line to the right (it becomes the last subhead of the line above it).|
|Control-L||Cmd-L||Move a line to the left (it becomes the next sibling of its former parent).|
To add a new line just place the cursor near the point and hit the return (enter) key.
There are menu commands for undo and entering HTML text. There are two basic modes, editing the structure and entering text.
 The Frontier environment
OPML boots as an outliner, but it's also a rich scripting environment, with a built-in web server, content management system, multi-threaded runtime. It's also a development environment with a full debugger and built-in object database.
All of it is organized by the outliner. Their are hierarchies are all over computer systems, so having it all organized with a rich hierarchy editor makes a huge amount of sense. It's also a rich environment for running apps, which you can find on the "Tool Catalog" page.
- Pandoc can convert this file format