Problem:
Using nested `vim.Pos` objects to represent each `vim.Range` object
requires 3 tables for each `vim.Range`, which may be undesirable in
performance critical code. Using key-value tables performs worse than
using array-like tables (lists).
Solution:
Use array-like indices for the internal fields of both `vim.Pos` and
`vim.Range` objects. Use a metatable to allow users to access them like
if they were key-value tables.
---
Problem:
The `vim.Pos` conversion interface for `extmark` indexing does not take
into account the difference in how a position on top of a newline is
represented in `vim.Pos` and `extmark`.
- `vim.Pos`: for a newline at the end of row `n`, `row` takes the value
`n + 1` and `col` takes the value `0`.
- `extmark`: for a newline at the end of for `n`, `row` takes the value
`n` and `col` takes the value `#row_text`.
Solution:
Handle this in the `extmark` interface.
---
Problem:
Not all `to_xxx` interfaces have wrapping objects like `to_lsp`.
Solution:
Return unwrapped values in `to_xxx` interfaces where it makes sense.
Accept unwrapped values in "from" interfaces where it makes sense.
---
Problem:
`start` and `end` positions have different semantics, so they can't be
compared. `vim.Range` relies on comparing the `end` and `start` of two
ranges to decide which one is greater, which doesn't work as expected
because this of the different semantics.
For example, for the ranges:
local a = {
start = { row = 0, col = 22, },
end_ = { row = 0, col = 24, },
}
local b = {
start = { row = 0, col = 17, },
end_ = { row = 0, col = 22, },
}
in this code:
local foo, bar = "foo", "bar"
-- |---||-|
-- b a
The range `b` is smaller than the range `a`, but the current
implementation compares `b._end` (`col = 22`) and `a.start` (`col = 22`)
and concludes that, since `b.col` is not smaller than `a.col`, `b`
should be greater than `a`.
Solution:
- Use a `to_inclusive_pos` to normalize end positions inside of
`vim.Range` whenever a comparison between a start and an end position
is necessary.
