Eric Hodel 2a65d43c13
Add into cell-path for dynamic cell-path creation (#11322)
# Description

The `cell-path` is a type that can be created statically with
`$.nested.structure.5`, but can't be created from user input. This makes
it difficult to take advantage of commands that accept a cell-path to
operate on data structures.

This PR adds `into cell-path` for dynamic cell-path creation.

`into cell-path` accepts the following input shapes:
* Bare integer (equivalent to `$.1`)
* List of strings and integers
* List of records with entries `value` and `optional`
* String (parsed into a cell-path)

## Example usage

An example of where `into cell-path` can be used is in working with `git
config --list`. The git configuration has a tree structure that maps
well to nushell records. With dynamic cell paths it is easy to convert
`git config list` to a record:

```nushell
git config --list
| lines
| parse -r '^(?<key>[^=]+)=(?<value>.*)'
| reduce --fold {} {|entry, result|
  let path = $entry.key | into cell-path

  $result
  | upsert $path {||
    $entry.value
  }
}
| select remote
```

Output:

```
╭────────┬──────────────────────────────────────────────────────────────────╮
│        │ ╭──────────┬───────────────────────────────────────────────────╮ │
│ remote │ │          │ ╭───────┬───────────────────────────────────────╮ │ │
│        │ │ upstream │ │ url   │ git@github.com:nushell/nushell.git    │ │ │
│        │ │          │ │ fetch │ +refs/heads/*:refs/remotes/upstream/* │ │ │
│        │ │          │ ╰───────┴───────────────────────────────────────╯ │ │
│        │ │          │ ╭───────┬─────────────────────────────────────╮   │ │
│        │ │ origin   │ │ url   │ git@github.com:drbrain/nushell      │   │ │
│        │ │          │ │ fetch │ +refs/heads/*:refs/remotes/origin/* │   │ │
│        │ │          │ ╰───────┴─────────────────────────────────────╯   │ │
│        │ ╰──────────┴───────────────────────────────────────────────────╯ │
╰────────┴──────────────────────────────────────────────────────────────────╯
```

## Errors

`lex()` + `parse_cell_path()` are forgiving about what is allowed in a
cell-path so it will allow what appears to be nonsense to become a
cell-path:

```nushell
let table = [["!@$%^&*" value]; [key value]]

$table | get ("!@$%^&*.0" | into cell-path)
# => key
```

But it will reject bad cell-paths:

```
❯ "a b" | into cell-path
Error: nu:🐚:cant_convert

  × Can't convert to cell-path.
   ╭─[entry #14:1:1]
 1 │ "a b" | into cell-path
   ·         ───────┬──────
   ·                ╰── can't convert string to cell-path
   ╰────
  help: "a b" is not a valid cell-path (Parse mismatch during operation.)
```

# User-Facing Changes

New conversion command `into cell-path`

# Tests + Formatting

- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

# After Submitting

Automatic documentation updates
2024-01-24 16:20:46 -06:00
..
2024-01-22 15:00:43 -06:00
2024-01-20 18:14:02 -06:00
2022-02-07 14:54:06 -05:00

Nushell core libraries and plugins

These sub-crates form both the foundation for Nu and a set of plugins which extend Nu with additional functionality.

Foundational libraries are split into two kinds of crates:

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  • Support crates - a set of crates that support the engine with additional features like JSON support, ANSI support, and more.

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  • Extra plugins - these plugins run a wide range of different capabilities like working with different file types, charting, viewing binary data, and more.