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Finishes implementing https://github.com/nushell/nushell/issues/10598,
which asks for a spread operator in lists, in records, and when calling
commands.
# Description
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This PR will allow spreading arguments to commands (both internal and
external). It will also deprecate spreading arguments automatically when
passing to external commands.
# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->
- Users will be able to use `...` to spread arguments to custom/builtin
commands that have rest parameters or allow unknown arguments, or to any
external command
- If a custom command doesn't have a rest parameter and it doesn't allow
unknown arguments either, the spread operator will not be allowed
- Passing lists to external commands without `...` will work for now but
will cause a deprecation warning saying that it'll stop working in 0.91
(is 2 versions enough time?)
Here's a function to help with demonstrating some behavior:
```nushell
> def foo [ a, b, c?, d?, ...rest ] { [$a $b $c $d $rest] | to nuon }
```
You can pass a list of arguments to fill in the `rest` parameter using
`...`:
```nushell
> foo 1 2 3 4 ...[5 6]
[1, 2, 3, 4, [5, 6]]
```
If you don't use `...`, the list `[5 6]` will be treated as a single
argument:
```nushell
> foo 1 2 3 4 [5 6] # Note the double [[]]
[1, 2, 3, 4, [[5, 6]]]
```
You can omit optional parameters before the spread arguments:
```nushell
> foo 1 2 3 ...[4 5] # d is omitted here
[1, 2, 3, null, [4, 5]]
```
If you have multiple lists, you can spread them all:
```nushell
> foo 1 2 3 ...[4 5] 6 7 ...[8] ...[]
[1, 2, 3, null, [4, 5, 6, 7, 8]]
```
Here's the kind of error you get when you try to spread arguments to a
command with no rest parameter:
And this is the warning you get when you pass a list to an external now
(without `...`):
# Tests + Formatting
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crates/nu-std"` to run the tests for the standard library
> **Note**
> from `nushell` you can also use the `toolkit` as follows
> ```bash
> use toolkit.nu # or use an `env_change` hook to activate it
automatically
> toolkit check pr
> ```
-->
Added tests to cover the following cases:
- Spreading arguments to a command that doesn't have a rest parameter
(unexpected spread argument error)
- Spreading arguments to a command that doesn't have a rest parameter
*but* there's also a missing positional argument (missing positional
error)
- Spreading arguments to a command that doesn't have a rest parameter
but does allow unknown arguments, such as `exec` (allowed)
- Spreading a list literal containing arguments of the wrong type (parse
error)
- Spreading a non-list value, both to internal and external commands
- Having named arguments in the middle of rest arguments
- `explain`ing a command call that spreads its arguments
# After Submitting
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documentation](https://github.com/nushell/nushell.github.io) after the
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# Examples
Suppose you have multiple tables:
```nushell
let people = [[id name age]; [0 alice 100] [1 bob 200] [2 eve 300]]
let evil_twins = [[id name age]; [0 ecila 100] [-1 bob 200] [-2 eve 300]]
```
Maybe you often find yourself needing to merge multiple tables and want
a utility to do that. You could write a function like this:
```nushell
def merge_all [ ...tables ] { $tables | reduce { |it, acc| $acc | merge $it } }
```
Then you can use it like this:
```nushell
> merge_all ...([$people $evil_twins] | each { |$it| $it | select name age })
╭───┬───────┬─────╮
│ # │ name │ age │
├───┼───────┼─────┤
│ 0 │ ecila │ 100 │
│ 1 │ bob │ 200 │
│ 2 │ eve │ 300 │
╰───┴───────┴─────╯
```
Except they had duplicate columns, so now you first want to suffix every
column with a number to tell you which table the column came from. You
can make a command for that:
```nushell
def select_and_merge [ --cols: list<string>, ...tables ] {
let renamed_tables = $tables
| enumerate
| each { |it|
$it.item | select $cols | rename ...($cols | each { |col| $col + ($it.index | into string) })
};
merge_all ...$renamed_tables
}
```
And call it like this:
```nushell
> select_and_merge --cols [name age] $people $evil_twins
╭───┬───────┬──────┬───────┬──────╮
│ # │ name0 │ age0 │ name1 │ age1 │
├───┼───────┼──────┼───────┼──────┤
│ 0 │ alice │ 100 │ ecila │ 100 │
│ 1 │ bob │ 200 │ bob │ 200 │
│ 2 │ eve │ 300 │ eve │ 300 │
╰───┴───────┴──────┴───────┴──────╯
```
---
Suppose someone's made a command to search for APT packages:
```nushell
# The main command
def search-pkgs [
--install # Whether to install any packages it finds
log_level: int # Pretend it's a good idea to make this a required positional parameter
exclude?: list<string> # Packages to exclude
repositories?: list<string> # Which repositories to look in (searches in all if not given)
...pkgs # Package names to search for
] {
{ install: $install, log_level: $log_level, exclude: ($exclude | to nuon), repositories: ($repositories | to nuon), pkgs: ($pkgs | to nuon) }
}
```
It has a lot of parameters to configure it, so you might make your own
helper commands to wrap around it for specific cases. Here's one
example:
```nushell
# Only look for packages locally
def search-pkgs-local [
--install # Whether to install any packages it finds
log_level: int
exclude?: list<string> # Packages to exclude
...pkgs # Package names to search for
] {
# All required and optional positional parameters are given
search-pkgs --install=$install $log_level [] ["<local URI or something>"] ...$pkgs
}
```
And you can run it like this:
```nushell
> search-pkgs-local --install=false 5 ...["python2.7" "vim"]
╭──────────────┬──────────────────────────────╮
│ install │ false │
│ log_level │ 5 │
│ exclude │ [] │
│ repositories │ ["<local URI or something>"] │
│ pkgs │ ["python2.7", vim] │
╰──────────────┴──────────────────────────────╯
```
One thing I realized when writing this was that if we decide to not
allow passing optional arguments using the spread operator, then you can
(mis?)use the spread operator to skip optional parameters. Here, I
didn't want to give `exclude` explicitly, so I used a spread operator to
pass the packages to install. Without it, I would've needed to do
`search-pkgs-local --install=false 5 [] "python2.7" "vim"` (explicitly
pass `[]` (or `null`, in the general case) to `exclude`). There are
probably more idiomatic ways to do this, but I just thought it was
something interesting.
If you're a virologist of the [xkcd](https://xkcd.com/350/) kind,
another helper command you might make is this:
```nushell
# Install any packages it finds
def live-dangerously [ ...pkgs ] {
# One optional argument was given (exclude), while another was not (repositories)
search-pkgs 0 [] ...$pkgs --install # Flags can go after spread arguments
}
```
Running it:
```nushell
> live-dangerously "git" "*vi*" # *vi* because I don't feel like typing out vim and neovim
╭──────────────┬─────────────╮
│ install │ true │
│ log_level │ 0 │
│ exclude │ [] │
│ repositories │ null │
│ pkgs │ [git, *vi*] │
╰──────────────┴─────────────╯
```
Here's an example that uses the spread operator more than once within
the same command call:
```nushell
let extras = [ chrome firefox python java git ]
def search-pkgs-curated [ ...pkgs ] {
(search-pkgs
1
[emacs]
["example.com", "foo.com"]
vim # A must for everyone!
...($pkgs | filter { |p| not ($p | str contains "*") }) # Remove packages with globs
python # Good tool to have
...$extras
--install=false
python3) # I forget, did I already put Python in extras?
}
```
Running it:
```nushell
> search-pkgs-curated "git" "*vi*"
╭──────────────┬───────────────────────────────────────────────────────────────────╮
│ install │ false │
│ log_level │ 1 │
│ exclude │ [emacs] │
│ repositories │ [example.com, foo.com] │
│ pkgs │ [vim, git, python, chrome, firefox, python, java, git, "python3"] │
╰──────────────┴───────────────────────────────────────────────────────────────────╯
```
This pull request fixes the tests for the `cargo.exe check` command. The
tests were failing due `cargo check -h` sometimes reporting `cargo.exe`
as the binary and thus not containing `cargo check` in the output.
The fix involves using the `Command` module from the `std::process`
library to run the command and comparing its output to the expected
output. No changes were made to the codebase itself.
# Description
_Fixes #5923_
Currently `nushell` doesn't allow short flag batches to contain
arguments, despite this being a common pattern in commands like `git
commit -am 'My commit message'`. This PR relaxes this so that the last
flag in the batch can take an argument.
# User-Facing Changes
- `nu::parser::short_flag_arg_cant_take_arg` has been replaced by
`nu::parser::only_last_flag_in_batch_can_take_arg` and is displayed when
a flag other then the last in a short flag batch takes an argument.
# Tests + Formatting
- Both
[`test_parser.rs`](48af0ebc3c/crates/nu-parser/tests/test_parser.rs (L640-L704))
and
[`test_known_external.rs`](48af0ebc3c/src/tests/test_known_external.rs (L42-L61))
have been updated to test the new allowed and disallowed scenarios.
---------
Co-authored-by: sholderbach <sholderbach@users.noreply.github.com>
