Should close#8035.
> **Note**
> this is my first technical PR for `nushell`
> - i might very well miss things
> - i tried to be as complete as possible about the changes
> - please require further changes if i did something wrong, i'm open to
any remark 😌
# Description
this PR adds, when it is defined in the `examples` method of the
`Command` implementations, the output of the examples to the output of
the `help` command.
this PR
- only modifies `crates/nu-engine/src/documentation.rs` and the
`get_documentation` function
- defines a new `WD` constant to print a **W**hite **D**immed `...`
- a `match` statement at the end of the example loop to
- print a white dimmed `...` when the example is not set, i.e. set to
`None` in the `examples` method of the `Command` implementation of a
command
- pretty print the output of the associated example `Value` when it has
been defined
> **Warning**
> LIMITATIONS:
> - i use snippets from `crates/nu-protocol/src/pipeline_data.rs`
> - the table creation from `pub PipelineData::print`, i.e. the `let
decl_id = ...;` and `let table = ...;` in the change
> - the table item printing from `PipelineData::write_all_and_flush`,
i.e. the `for item in table { ... }`
>
> ADDRESSED:
> - ~~the formatting of the output is not perfect and has to be fully
left aligned with the first column for now~~ (fixed with
[`5abeefd558c34ba9bae15e2f183ff4625442921e`..`a62be1b5a2c730959da5dbc028bb91ffe5093f63`](5abeefd558c34ba9bae15e2f183ff4625442921e..a62be1b5a2c730959da5dbc028bb91ffe5093f63))
> - ~~i'm using `.unwrap()` on both the changes above, not sure how to
handle this for now~~ (fixed for now thanks to 49f1dc080)
> - ~~the tests and `clippy` checks do not pass for now, see below~~
(`clippy` now is happy with 49f1dc080 and the tests pass with
11666bc715)
# User-Facing Changes
the output of the `help <command>` command is now augmented with the
outputs of the examples, when they are defined.
- `with-env`
```bash
> help with-env
...
Examples:
Set the MYENV environment variable
> with-env [MYENV "my env value"] { $env.MYENV }
my env value
Set by primitive value list
> with-env [X Y W Z] { $env.X }
Y
Set by single row table
> with-env [[X W]; [Y Z]] { $env.W }
Z
Set by key-value record
> with-env {X: "Y", W: "Z"} { [$env.X $env.W] }
╭───┬───╮
│ 0 │ Y │
│ 1 │ Z │
╰───┴───╯
```
instead of the previous
```bash
> help with-env
...
Examples:
Set the MYENV environment variable
> with-env [MYENV "my env value"] { $env.MYENV }
Set by primitive value list
> with-env [X Y W Z] { $env.X }
Set by single row table
> with-env [[X W]; [Y Z]] { $env.W }
Set by key-value record
> with-env {X: "Y", W: "Z"} { [$env.X $env.W] }
```
- `merge`
```bash
> help merge
...
Examples:
Add an 'index' column to the input table
> [a b c] | wrap name | merge ( [1 2 3] | wrap index )
╭───┬──────╮
│ # │ name │
├───┼──────┤
│ 1 │ a │
│ 2 │ b │
│ 3 │ c │
╰───┴──────╯
Merge two records
> {a: 1, b: 2} | merge {c: 3}
╭───┬───╮
│ a │ 1 │
│ b │ 2 │
│ c │ 3 │
╰───┴───╯
Merge two tables, overwriting overlapping columns
> [{columnA: A0 columnB: B0}] | merge [{columnA: 'A0*'}]
╭───┬─────────┬─────────╮
│ # │ columnA │ columnB │
├───┼─────────┼─────────┤
│ 0 │ A0* │ B0 │
╰───┴─────────┴─────────╯
```
instead of the previous
```bash
> help merge
...
Examples:
Add an 'index' column to the input table
> [a b c] | wrap name | merge ( [1 2 3] | wrap index )
Merge two records
> {a: 1, b: 2} | merge {c: 3}
Merge two tables, overwriting overlapping columns
> [{columnA: A0 columnB: B0}] | merge [{columnA: 'A0*'}]
```
2492165fcb