This is initial support for type-aware tab completion. When you hit tab, it tries to complete the word you're in the middle of using a face or arm in the subject at that point in the code. It also shows all possible matches and their associated types. It's nearly instantaneous. Notes:
- It advances to the longest common prefix, so if you hit tab on `ab` and the only possible results are `abcde` and `abcdz`, then it'll write `abcd` and print both out (with their types).
- If there are fewer than ten matches, it prints the type along with the face. Printing types is too slow to use all the time, but with 10 it's essentially instantaneous.
- The match closest in the subject to you (i.e. smallest axis number) is displayed lowest (closest to your focus).
Examples below, where `<TAB>` represents me hitting tab while my cursor is at that position (the line with the `<TAB>` is not preserved in the actual output).
```
~zod:dojo> eth<TAB>
-----
ethereum #t/<11.qcl {<3.ltb 27.ipf 7.ecf 36.uek 92.bjk 247.ows 51.mvt 126.xjf 41.mac 1.ane $141> <21.yeb 27.ipf 7.ecf 36.uek 92.bjk 247.ows 51.mvt 126.xjf 41.mac 1.ane $141>}>
ethereum-types #t/<3.ltb 27.ipf 7.ecf 36.uek 92.bjk 247.ows 51.mvt 126.xjf 41.mac 1.ane $141>
~zod:dojo> ethereum
~zod:dojo> |= zong=@ud z<TAB>
-----
zing #t/<1.dqs {* <126.xjf 41.mac 1.ane $141>}>
zap #t/<1.iot {tub/{p/{p/@ud q/@ud} q/""} <1.rff {daf/@t <247.ows 51.mvt 126.xjf 41.mac 1.ane $141>}>}>
zuse #t/$309
zong #t/@ud
~zod:dojo> |= zong=@ud zo<TAB>
-----
zong #t/@ud
~zod:dojo> |= zong=@ud zong
~zod:dojo> <TAB>
hoon-version
trel
quip
pole
unit
qual
lone
... about 600 more lines ...
unity
html
zuse
eny
now
our
~zod:dojo>
```
Functionally, this is in a state where I'd be comfortable shipping it. It doesn't interfere with anything if you don't press tab, and it's perfectly OTA-able. I do think its output is a little verbose, but that can be tuned over time as people try it and determine what feels good in practice.
Additional notes:
- There are plenty of similar systems for other languages, but my most direct inspiration is Idris's editor tools. This is implemented for the dojo, but I actually want it in my editor, which is why the meat is all defind in a library. I've only tested on dojo one-liners, so I don't know the performance on large blocks of code.
- The default type printer isn't great for this use case. In particular,
- Cores should not print anything about their context
- The `#t/` should go away
- If it looks like a gate, we should print its return value
- Maybe special handling for molds, but if the above is done, then for example `bone` is `* -> @ud`.
- The worst part about our wing ordering is that it really screws up tab completion. You want to do `point.owner-address` instead of `owner-address.point` because that lets you type `point.ow<TAB>`. I weakly prefer reading it how we do it now, but it's really not great. You could do an (dojo-specific?) alternate syntax of `point;owner-address`; this is a simple transformation.
- Regardless of the above, this should handle the case where we're in the middle of defining a wing; it doesn't right now.
- When a variable is shadowed, we show both of them. We should probably show the shadowed one with a `^`.
- We probably shouldn't print out hundreds of results. Maybe just the closest 50 with ellipses.
- This gets you any face in your subject, regardless of whether its type is reasonable. We could limit that some by copying the `gol` logic in mint, so that if the pseudo-backward-inference engine happens to know what type it should be, you can filter the tab results according to if they nest in that type. This would be "strongly type-aware".
