I spent some time trying to reduce the duplication between identical
operations with and without the shift key pressed. However it makes
things harder to understand. If you try to process selection in
App.keychord_pressed in main.lua, you have to sometimes process the
selection before (e.g. including the state of the cursor _before_ an
arrow key takes effect), and sometimes after (e.g. copying the selection
before resetting it, even though it doesn't include a shift key)
Let's just leave things as they are.
I've written a few tests for delete_selection, but the way different
operations initialize the selection seems fairly standard and not worth
testing so far.
I'm now extracting the concern of computing
line.screen_line_starting_pos out of Text.draw. Earlier
I had to make sure I ran through the whole line to compute
screen_line_starting_pos, but that had the side-effect of updating
Screen_bottom1.pos as well with lines that had never been rendered.
In this process I hit my first bug due to an accidental global. It
doesn't show up in the patch because I accidentally deleted a local
declaration. (I thought I didn't need screen_line_starting_pos anymore,
deleted everywhere, then brought it back everywhere from the bottom of
the function up, but forgot to put back the very first occurrence.)
The amount of yoyoing this caused between App.draw and Text.draw, I very
much have spaghetti on my hands.
Accidental globals are _terrible_ in a program with tests. Cross test
contamination X-(
I also really need to rethink how people debug my programs. My approach
of inserting and deleting print() takes a lot of commitment. I need my
old trace-based whitebox testing idea. However, in my past projects I
never did figure out a good framework for tweaking how verbose a trace
to emit.
Perhaps that's too many knobs. Perhaps we just need a way to run a
single test with the most verbose trace possible. Then it's just a
matter of having the trace tell a coherent story? But even if the trace
stays out of program output in that situation, it's still in the
programmer's face in the _code_. Ugh.
Current plan: ship program with maximum tests and zero commented-out
prints. If you want to debug, insert prints. This is better than
previous, text-mode, projects just by virtue of the stdout channel being
dedicated to debug stuff.