[Toybox] Editors and such.

[David Seikel]

On Sat, 30 Jun 2012 18:00:08 -0500 Rob Landley <rob at landley.net> wrote:

> On 06/30/2012 03:42 PM, David Seikel wrote:
> >> There are times scrolling existing text would be nice. Keep in mind
> >> that's half of what "less" does".
> > 
> > I did not mean the functionality of scrolling text, I meant using
> > escape sequences for scrolling text.  It already scrolls text, it
> > just does a screen redraw instead of trying to figure out which bit
> > of the screen it can scroll with escape sequences first before
> > drawing the rest.
> 
> I'm currently debugging a horrible fedora-only build issue where
> running a shell script snippet via /bin/bash inserts stuff at the
> start of the $PATH for some reason. (Maybe /etc/profile? Fedora is
> horribly overcomplicated.) This, like everything else, breaks cross
> compiling.
> 
> I'm running it under kvm, where screen writes are extremely expensive
> due to the 2D sdl graphics card emulation.
> 
> Scrolling the screen is a bitblt, but redrawing the screen is slow
> enough that I can see the characters redraw in the xterm.
> 
> This means cursoring down in another less implementation will be
> essentially instantaneous in otherimplementations, and will take a
> couple seconds per cursor-down key in the one you're proposing.
> 
> Saving redrawing half a line is useless, but redrawing the entire
> screen unnecessarily rather than moving the lines of text up/down is
> still pretty noticeable.
> 
> > This is one of the reasons I was checking if we ever have to deal
> > with slow connections.  Fast ones can handle complete redraws for
> > paging and scrolling, and that keeps the code simple.  Optimized
> > redraws can come later if we feel it's needed.
> 
> Optimizing redraws is more complicated than it's worth, but _avoiding_
> redraws is a pretty common case that can be expensive in certain
> contexts. (Scrolling up or down, happens a lot.)

It is on my TODO to see what optimizations I can do simply.  I want to
get it correct first though.

> > And people will scream if I leave out emacs.  shrugs
> 
> I honestly don't care, but if it's easy to do...

I don't care about emacs or vi, but vi is apparently mandatory, though
hideous, and basic emacs should be trivial, with a full emacs being
more hideous.  Simple emacs, yep easy to do, could almost do it now.
Microemacs subset, most likely I'll do it.  Full emacs, not gonna
happen.

-- 
A big old stinking pile of genius that no one wants
coz there are too many silver coated monkeys in the world.
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