Features

Automatic handling of window resizes.
Supports Unicode characters on output, automatically setting and resetting UTF-8 mode for xterm. Other terminals are assumed to support
Efficient output.
Minimizes repaint area, thus virtually eliminating the flicker problem that plagues ncurses programs.
A pure, compositional interface for efficiently constructing display images.
Automatically decodes keyboard keys into (key,[modifier]) tuples.
Automatically supports refresh on Ctrl-L.
Automatically supports timeout after 50ms for lone ESC (a barely noticable delay)
Interface is designed for relatively easy compatible extension.
Supports all ANSI SGR-modes (defined in console_codes(4)) with a type-safe interface.
Properly handles cleanup.

Known Issues

The character encoding of the output terminal is assumed to be UTF-8.
Minimal support for special keys on terminals other than the linux-console. (F1-5 and arrow keys should work, but anything shifted isn't likely to.)
Uses the TIOCGWINSZ ioctl to find the current window size, which appears to be limited to Linux and *BSD.

Platform Support

Posix Terminals

Uses terminfo to determine terminal protocol. Some special rules for Mac terminal applications. The special rules might be invalid on newer Mac OS.

Windows

None!

Development Notes

Coverage

On my system the hpc coverage mix file receives a bad hash when using template haskell. This means Graphics.Vty.Span needs to have the hash value fixed after being re-generated. I just pull the expected hash from the first tix file that fails. The error message is unhelpful:

hpc: can not find vty-5.0.0/Graphics.Vty.Span in ["./dist/hpc/mix/vty-5.0.0"]

which is incorrect: The file can be found but the hash is incorrect.