Simple frp text editor for testing and learning purposes.
The text editor can currently edit and show text.
Planned features are (in order of importance):
- Can edit text.
- Has a viewport.
- Supports line wrapping.
- Can read and write files.
Long term goals:
- Supports the Language Server Protocol (using haskell-lsp-client).
- Has vim keybindings.
- Has a browser frontend (this is the reason for the AGPL license).
Feel free to contact me (for example by opening an issue here) if you would like to have any other design decisions explained.
I chose to use frpnow mainly because it promises an efficient implementation and it doesn't have many extraneous features which I probably won't need and will only get in the way of learning how to use it.
The main alternatives for me would be Yampa, but I didn't want to learn how to use the arrow interface. Or maybe reflex when I'm more comfortable with FRP.
I have now learned how to use the arrow interface, it is not too hard. I think that the new Yampa implementation is much nicer than the previous frpnow implementation.
I am using explicit data types for each different type of integer. I hope this will prevent most mistakes that can happen.
The main disadvantage of this is that conversions between the types need to be explicitely specified by the programmer, but I personally really like it when all the types logically fit together.
I have decided to split the viewport, cursor and content. This should improve the readability and modularity of the code. A disadvantage is that some internal information is lost so some functions may have worse performance, but it shouldn't influence the worst case time complexity.
When implementing this I really noticed that the code became much more readable.