# Description
Our `ShellError` at the moment has a `std::mem::size_of<ShellError>` of
136 bytes (on AMD64). As a result `Value` directly storing the struct
also required 136 bytes (thanks to alignment requirements).
This change stores the `Value::Error` `ShellError` on the heap.
Pro:
- Value now needs just 80 bytes
- Should be 1 cacheline less (still at least 2 cachelines)
Con:
- More small heap allocations when dealing with `Value::Error`
- More heap fragmentation
- Potential for additional required memcopies
# Further code changes
Includes a small refactor of `try` due to a type mismatch in its large
match.
# User-Facing Changes
None for regular users.
Plugin authors may have to update their matches on `Value` if they use
`nu-protocol`
Needs benchmarking to see if there is a benefit in real world workloads.
**Update** small improvements in runtime for workloads with high volume
of values. Significant reduction in maximum resident set size, when many
values are held in memory.
# Tests + Formatting
A small but easy optimization for `evaluate_repl()`: clone
`engine_state` 1x instead of 3x.
This reduces time spent in a simple REPL eval (`enter` key pressed with
no command text) by about 10%, as measured in
[Superluminal](https://superluminal.eu/).
At the moment `crossterm` apparently has a regression decoding certain important key combinations on Windows.
Thus reedline reverted to the previous version.
Some changes are necessary to remove the need for `crossterm` in the use of `lscolors`.
Introduces two local conversion traits.
Additionally update the `Highlighter` API to support the cursor
position.
This will enable brace/statement match highlighting.
