nushell/crates/nu-protocol/src
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
..
ast Add into cell-path for dynamic cell-path creation (#11322) 2024-01-24 16:20:46 -06:00
config Add CLI flag to disable history (#11550) 2024-01-17 09:40:59 -06:00
engine Add CLI flag to disable history (#11550) 2024-01-17 09:40:59 -06:00
value Upgrade byte-unit from 4.0 to 5.1 (#11584) 2024-01-21 14:17:28 -06:00
alias.rs Refactor scope commands (#10023) 2023-08-17 11:58:38 +03:00
cli_error.rs Refactor and fix Config<->Value mechanism (#10896) 2023-11-08 20:31:30 +01:00
did_you_mean.rs Improve case insensitivity consistency (#10884) 2023-11-08 23:58:54 +01:00
eval_base.rs Evaluate string interpolation at parse time (#11562) 2024-01-22 09:13:48 +02:00
eval_const.rs Evaluate string interpolation at parse time (#11562) 2024-01-22 09:13:48 +02:00
example.rs remove unused imports: Deserialize, Serialize compiler warning for nu-protocol/src/example.rs (#8514) 2023-03-18 11:45:12 -07:00
exportable.rs Module: support defining const and use const variables inside of function (#9773) 2023-08-01 07:09:52 +08:00
id.rs Add virtual path abstraction layer (#9245) 2023-05-23 23:48:50 +03:00
lev_distance.rs Suggest existing variables on not found (#8902) 2023-05-02 18:17:14 +03:00
lib.rs Deprecate --flag: bool in custom command (#11365) 2023-12-21 10:07:08 +01:00
module.rs Error on use path item1 item2, if item1 is not a module (#11183) 2023-12-05 11:38:45 +01:00
parse_error.rs Evaluate string interpolation at parse time (#11562) 2024-01-22 09:13:48 +02:00
parse_warning.rs Deprecate --flag: bool in custom command (#11365) 2023-12-21 10:07:08 +01:00
pipeline_data.rs Don't create a thread if stderr_stream is None (#11421) 2023-12-25 08:10:15 -06:00
plugin_signature.rs Rename main to script name when running scripts (#9948) 2023-08-12 05:58:49 +12:00
shell_error.rs Allow spreading arguments to commands (#11289) 2023-12-28 15:43:20 +08:00
signature.rs Move history into their own module (#11308) 2023-12-15 13:17:12 +01:00
span.rs Use variable names directly in the format strings (#7906) 2023-01-29 19:37:54 -06:00
syntax_shape.rs do not attempt to glob expand if the file path is wrapped in quotes (#11569) 2024-01-21 23:22:25 +08:00
ty.rs adjust some commansd input_output type (#11436) 2024-01-15 16:58:26 +08:00
util.rs Convert more ShellError variants to named fields (#11173) 2023-11-28 06:43:51 -06:00
variable.rs Fix broken constants in scopes (#9679) 2023-07-14 00:02:05 +03:00