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Surprised to see that this doesn't use ncurses at all. I was really hoping to see something that brought the painlessness of using React to building an ncurses

Surprised to see that this doesn't use ncurses at all. I was really hoping to see something that brought the painlessness of using React to building an ncurses textual interface. Seeing that it doesn't use ncurses, I'm suspicious of how it does re-draws. I'd imagine the naive thing of just redrawing every bit of text on the screen for every reactive event would work, but be pretty slow. Of course, if they're doing something smarter than this, I'd be interested to hear how it's done.

xiaq 9y ago
If you keep an internal representation of the terminal (which you should totally do when building a terminal toolkit), you can just update whatever changed. It is not hard with cursor positioning sequences.
- ams6110 9y ago
  This is what [n]curses does, since decades ago.
  - xiaq 9y ago
    Well, my point is that everyone can do this, ncurses is no black magic :)
Siilwyn 9y ago
Think [react-blessed](https://github.com/Yomguithereal/react-blessed https://github.com/Yomguithereal/react-blessed) comes close to what you're thinking of.
thomasballinger 9y ago
One optimization that's not hard to do for terminal output is a line cache: if a row is the same, don't render it. The rendering logic is probably already operating on lines, so this doesn't require the fancy diffing; but diffing a flat grid seems easier anyway vs the dom tree. For context, (I suspect parent already understands this) this is analogous to the vdom optimizations (not shouldComponentUpdate optimizations) possible with React. Except the algorithm is more straightforward: for each character on the grid, is the content the same since the previous render? This library looks real neat, a declarative TUI with an api already familiar to many developers. I've thought this would be a neat thing to exist since I started using React after having written a similar declarative, redraw-only-as-necessary terminal rendering library for bpython (http://ballingt.com/bpython-curtsies/ http://ballingt.com/bpython-curtsies/). In it (http://curtsies.readthedocs.io/en/latest/ http://curtsies.readthedocs.io/en/latest/) the only rendering optimization was a line cache. For the specific use case of an interactive interpreter this worked pretty well: once a line is changing, it's probably changing a lot. But you could go further using the output of diffing of arrays of terminal text. edit: whoa https://github.com/Yomguithereal/react-blessed https://github.com/Yomguithereal/react-blessed looks awesome for this

xiaq 9y ago

If you keep an internal representation of the terminal (which you should totally do when building a terminal toolkit), you can just update whatever changed. It is not hard with cursor positioning sequences.

ams6110 9y ago
This is what [n]curses does, since decades ago.
- xiaq 9y ago
  Well, my point is that everyone can do this, ncurses is no black magic :)

Siilwyn 9y ago

Think [react-blessed](https://github.com/Yomguithereal/react-blessed https://github.com/Yomguithereal/react-blessed) comes close to what you're thinking of.

thomasballinger 9y ago

One optimization that's not hard to do for terminal output is a line cache: if a row is the same, don't render it. The rendering logic is probably already operating on lines, so this doesn't require the fancy diffing; but diffing a flat grid seems easier anyway vs the dom tree. For context, (I suspect parent already understands this) this is analogous to the vdom optimizations (not shouldComponentUpdate optimizations) possible with React. Except the algorithm is more straightforward: for each character on the grid, is the content the same since the previous render? This library looks real neat, a declarative TUI with an api already familiar to many developers. I've thought this would be a neat thing to exist since I started using React after having written a similar declarative, redraw-only-as-necessary terminal rendering library for bpython (http://ballingt.com/bpython-curtsies/ http://ballingt.com/bpython-curtsies/). In it (http://curtsies.readthedocs.io/en/latest/ http://curtsies.readthedocs.io/en/latest/) the only rendering optimization was a line cache. For the specific use case of an interactive interpreter this worked pretty well: once a line is changing, it's probably changing a lot. But you could go further using the output of diffing of arrays of terminal text. edit: whoa https://github.com/Yomguithereal/react-blessed https://github.com/Yomguithereal/react-blessed looks awesome for this