# Description
When implementing a `Command`, one must also import all the types
present in the function signatures for `Command`. This makes it so that
we often import the same set of types in each command implementation
file. E.g., something like this:
```rust
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
ShellError, Signature, Span, Type, Value,
};
```
This PR adds the `nu_engine::command_prelude` module which contains the
necessary and commonly used types to implement a `Command`:
```rust
// command_prelude.rs
pub use crate::CallExt;
pub use nu_protocol::{
ast::{Call, CellPath},
engine::{Command, EngineState, Stack},
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, IntoSpanned,
PipelineData, Record, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
```
This should reduce the boilerplate needed to implement a command and
also gives us a place to track the breadth of the `Command` API. I tried
to be conservative with what went into the prelude modules, since it
might be hard/annoying to remove items from the prelude in the future.
Let me know if something should be included or excluded.
# Description
The PR overhauls how IO redirection is handled, allowing more explicit
and fine-grain control over `stdout` and `stderr` output as well as more
efficient IO and piping.
To summarize the changes in this PR:
- Added a new `IoStream` type to indicate the intended destination for a
pipeline element's `stdout` and `stderr`.
- The `stdout` and `stderr` `IoStream`s are stored in the `Stack` and to
avoid adding 6 additional arguments to every eval function and
`Command::run`. The `stdout` and `stderr` streams can be temporarily
overwritten through functions on `Stack` and these functions will return
a guard that restores the original `stdout` and `stderr` when dropped.
- In the AST, redirections are now directly part of a `PipelineElement`
as a `Option<Redirection>` field instead of having multiple different
`PipelineElement` enum variants for each kind of redirection. This
required changes to the parser, mainly in `lite_parser.rs`.
- `Command`s can also set a `IoStream` override/redirection which will
apply to the previous command in the pipeline. This is used, for
example, in `ignore` to allow the previous external command to have its
stdout redirected to `Stdio::null()` at spawn time. In contrast, the
current implementation has to create an os pipe and manually consume the
output on nushell's side. File and pipe redirections (`o>`, `e>`, `e>|`,
etc.) have precedence over overrides from commands.
This PR improves piping and IO speed, partially addressing #10763. Using
the `throughput` command from that issue, this PR gives the following
speedup on my setup for the commands below:
| Command | Before (MB/s) | After (MB/s) | Bash (MB/s) |
| --------------------------- | -------------:| ------------:|
-----------:|
| `throughput o> /dev/null` | 1169 | 52938 | 54305 |
| `throughput \| ignore` | 840 | 55438 | N/A |
| `throughput \| null` | Error | 53617 | N/A |
| `throughput \| rg 'x'` | 1165 | 3049 | 3736 |
| `(throughput) \| rg 'x'` | 810 | 3085 | 3815 |
(Numbers above are the median samples for throughput)
This PR also paves the way to refactor our `ExternalStream` handling in
the various commands. For example, this PR already fixes the following
code:
```nushell
^sh -c 'echo -n "hello "; sleep 0; echo "world"' | find "hello world"
```
This returns an empty list on 0.90.1 and returns a highlighted "hello
world" on this PR.
Since the `stdout` and `stderr` `IoStream`s are available to commands
when they are run, then this unlocks the potential for more convenient
behavior. E.g., the `find` command can disable its ansi highlighting if
it detects that the output `IoStream` is not the terminal. Knowing the
output streams will also allow background job output to be redirected
more easily and efficiently.
# User-Facing Changes
- External commands returned from closures will be collected (in most
cases):
```nushell
1..2 | each {|_| nu -c "print a" }
```
This gives `["a", "a"]` on this PR, whereas this used to print "a\na\n"
and then return an empty list.
```nushell
1..2 | each {|_| nu -c "print -e a" }
```
This gives `["", ""]` and prints "a\na\n" to stderr, whereas this used
to return an empty list and print "a\na\n" to stderr.
- Trailing new lines are always trimmed for external commands when
piping into internal commands or collecting it as a value. (Failure to
decode the output as utf-8 will keep the trailing newline for the last
binary value.) In the current nushell version, the following three code
snippets differ only in parenthesis placement, but they all also have
different outputs:
1. `1..2 | each { ^echo a }`
```
a
a
╭────────────╮
│ empty list │
╰────────────╯
```
2. `1..2 | each { (^echo a) }`
```
╭───┬───╮
│ 0 │ a │
│ 1 │ a │
╰───┴───╯
```
3. `1..2 | (each { ^echo a })`
```
╭───┬───╮
│ 0 │ a │
│ │ │
│ 1 │ a │
│ │ │
╰───┴───╯
```
But in this PR, the above snippets will all have the same output:
```
╭───┬───╮
│ 0 │ a │
│ 1 │ a │
╰───┴───╯
```
- All existing flags on `run-external` are now deprecated.
- File redirections now apply to all commands inside a code block:
```nushell
(nu -c "print -e a"; nu -c "print -e b") e> test.out
```
This gives "a\nb\n" in `test.out` and prints nothing. The same result
would happen when printing to stdout and using a `o>` file redirection.
- External command output will (almost) never be ignored, and ignoring
output must be explicit now:
```nushell
(^echo a; ^echo b)
```
This prints "a\nb\n", whereas this used to print only "b\n". This only
applies to external commands; values and internal commands not in return
position will not print anything (e.g., `(echo a; echo b)` still only
prints "b").
- `complete` now always captures stderr (`do` is not necessary).
# After Submitting
The language guide and other documentation will need to be updated.
# Description
Following from #11356, it looks like `Expr::MatchPattern` is no longer
used in any way. This PR removes `Expr::MatchPattern` alongside
`Type::MatchPattern` and `SyntaxShape::MatchPattern`.
# User-Facing Changes
Breaking API change for `nu_protocol`.
## description
this pr adds [match
guards](https://doc.rust-lang.org/reference/expressions/match-expr.html#match-guards)
to match patterns
```nushell
match $x {
_ if $x starts-with 'nu' => {},
$x => {}
}
```
these work pretty much like rust's match guards, with few limitations:
1. multiple matches using the `|` are not (yet?) supported
```nushell
match $num {
0 | _ if (is-odd $num) => {},
_ => {}
}
```
2. blocks cannot be used as guards, (yet?)
```nushell
match $num {
$x if { $x ** $x == inf } => {},
_ => {}
}
```
## checklist
- [x] syntax
- [x] syntax highlighting[^1]
- [x] semantics
- [x] tests
- [x] clean up
[^1]: defered for another pr
# Description
This removes some unnecessary SyntaxShapes when parsing a
SyntaxShape::Any. Recent updates to the parser look for `{` and then
handle the logic for that separately.
# User-Facing Changes
This may have a slight parser speedup.
# Tests + Formatting
<!--
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect -A clippy::result_large_err` to check that
you're using the standard code style
- `cargo test --workspace` to check that all tests pass
- `cargo run -- crates/nu-std/tests/run.nu` 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
> ```
-->
# After Submitting
<!-- If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
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# Description
This is a pretty heavy refactor of the parser to support multiple parser
errors. It has a few issues we should address before landing:
- [x] In some cases, error quality has gotten worse `1 / "bob"` for
example
- [x] if/else isn't currently parsing correctly
- probably others
# User-Facing Changes
This may have error quality degradation as we adjust to the new error
reporting mechanism.
# Tests + Formatting
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
- `cargo run -- crates/nu-utils/standard_library/tests.nu` 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
> ```
# After Submitting
If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
# Description
Adds two more patterns when working with lists:
```
[1, ..$remainder]
```
and
```
[1, ..]
```
The first one collects the remaining items and assigns them into the
variable. The second one ignores any remaining values.
# User-Facing Changes
Adds more capability to list pattern matching.
# Tests + Formatting
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
- `cargo run -- crates/nu-utils/standard_library/tests.nu` 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
> ```
# After Submitting
If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
# Description
Adds `|` patterns to `match`, allowing you to try multiple patterns for
the same case.
Example:
```
match {b: 1} { {a: $b} | {b: $b} => { print $b } }
```
Variables that don't bind are set to `$nothing` so that they can be
later checked.
This PR also:
fixes#8631
Creates a set of integration tests for pattern matching also
# User-Facing Changes
Adds `|` to `match`. Fixes variable binding scope.
# Tests + Formatting
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
> **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
> ```
# After Submitting
If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
# Description
This does a couple random changes/fixes:
* Moves `timeit` to use a block instead of a closure. This makes it a
bit more flexible.
* Moves var bindings in patterns to be immutable
# User-Facing Changes
`timeit` now takes a block and no arguments.
# Tests + Formatting
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
> **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
> ```
# After Submitting
If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
# Description
This adds `match` and basic pattern matching.
An example:
```
match $x {
1..10 => { print "Value is between 1 and 10" }
{ foo: $bar } => { print $"Value has a 'foo' field with value ($bar)" }
[$a, $b] => { print $"Value is a list with two items: ($a) and ($b)" }
_ => { print "Value is none of the above" }
}
```
Like the recent changes to `if` to allow it to be used as an expression,
`match` can also be used as an expression. This allows you to assign the
result to a variable, eg) `let xyz = match ...`
I've also included a short-hand pattern for matching records, as I think
it might help when doing a lot of record patterns: `{$foo}` which is
equivalent to `{foo: $foo}`.
There are still missing components, so consider this the first step in
full pattern matching support. Currently missing:
* Patterns for strings
* Or-patterns (like the `|` in Rust)
* Patterns for tables (unclear how we want to match a table, so it'll
need some design)
* Patterns for binary values
* And much more
# User-Facing Changes
[see above]
# Tests + Formatting
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
> **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
> ```
# After Submitting
If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.