This is a follow up from https://github.com/nushell/nushell/pull/7540.
Please provide feedback if you have the time!
## Summary
This PR lets you use `?` to indicate that a member in a cell path is
optional and Nushell should return `null` if that member cannot be
accessed.
Unlike the previous PR, `?` is now a _postfix_ modifier for cell path
members. A cell path of `.foo?.bar` means that `foo` is optional and
`bar` is not.
`?` does _not_ suppress all errors; it is intended to help in situations
where data has "holes", i.e. the data types are correct but something is
missing. Type mismatches (like trying to do a string path access on a
date) will still fail.
### Record Examples
```bash
{ foo: 123 }.foo # returns 123
{ foo: 123 }.bar # errors
{ foo: 123 }.bar? # returns null
{ foo: 123 } | get bar # errors
{ foo: 123 } | get bar? # returns null
{ foo: 123 }.bar.baz # errors
{ foo: 123 }.bar?.baz # errors because `baz` is not present on the result from `bar?`
{ foo: 123 }.bar.baz? # errors
{ foo: 123 }.bar?.baz? # returns null
```
### List Examples
```
〉[{foo: 1} {foo: 2} {}].foo
Error: nu:🐚:column_not_found
× Cannot find column
╭─[entry #30:1:1]
1 │ [{foo: 1} {foo: 2} {}].foo
· ─┬ ─┬─
· │ ╰── cannot find column 'foo'
· ╰── value originates here
╰────
〉[{foo: 1} {foo: 2} {}].foo?
╭───┬───╮
│ 0 │ 1 │
│ 1 │ 2 │
│ 2 │ │
╰───┴───╯
〉[{foo: 1} {foo: 2} {}].foo?.2 | describe
nothing
〉[a b c].4? | describe
nothing
〉[{foo: 1} {foo: 2} {}] | where foo? == 1
╭───┬─────╮
│ # │ foo │
├───┼─────┤
│ 0 │ 1 │
╰───┴─────╯
```
# Breaking changes
1. Column names with `?` in them now need to be quoted.
2. The `-i`/`--ignore-errors` flag has been removed from `get` and
`select`
1. After this PR, most `get` error handling can be done with `?` and/or
`try`/`catch`.
4. Cell path accesses like this no longer work without a `?`:
```bash
〉[{a:1 b:2} {a:3}].b.0
2
```
We had some clever code that was able to recognize that since we only
want row `0`, it's OK if other rows are missing column `b`. I removed
that because it's tricky to maintain, and now that query needs to be
written like:
```bash
〉[{a:1 b:2} {a:3}].b?.0
2
```
I think the regression is acceptable for now. I plan to do more work in
the future to enable streaming of cell path accesses, and when that
happens I'll be able to make `.b.0` work again.
# Description
Our `ShellError` at the moment has a `std::mem::size_of<ShellError>` of
136 bytes (on AMD64). As a result `Value` directly storing the struct
also required 136 bytes (thanks to alignment requirements).
This change stores the `Value::Error` `ShellError` on the heap.
Pro:
- Value now needs just 80 bytes
- Should be 1 cacheline less (still at least 2 cachelines)
Con:
- More small heap allocations when dealing with `Value::Error`
- More heap fragmentation
- Potential for additional required memcopies
# Further code changes
Includes a small refactor of `try` due to a type mismatch in its large
match.
# User-Facing Changes
None for regular users.
Plugin authors may have to update their matches on `Value` if they use
`nu-protocol`
Needs benchmarking to see if there is a benefit in real world workloads.
**Update** small improvements in runtime for workloads with high volume
of values. Significant reduction in maximum resident set size, when many
values are held in memory.
# Tests + Formatting
Continuation of #8229 and #8326
# Description
The `ShellError` enum at the moment is kind of messy.
Many variants are basic tuple structs where you always have to reference
the implementation with its macro invocation to know which field serves
which purpose.
Furthermore we have both variants that are kind of redundant or either
overly broad to be useful for the user to match on or overly specific
with few uses.
So I set out to start fixing the lacking documentation and naming to
make it feasible to critically review the individual usages and fix
those.
Furthermore we can decide to join or split up variants that don't seem
to be fit for purpose.
# Call to action
**Everyone:** Feel free to add review comments if you spot inconsistent
use of `ShellError` variants.
# User-Facing Changes
(None now, end goal more explicit and consistent error messages)
# Tests + Formatting
(No additional tests needed so far)
# Commits (so far)
- Remove `ShellError::FeatureNotEnabled`
- Name fields on `SE::ExternalNotSupported`
- Name field on `SE::InvalidProbability`
- Name fields on `SE::NushellFailed` variants
- Remove unused `SE::NushellFailedSpannedHelp`
- Name field on `SE::VariableNotFoundAtRuntime`
- Name fields on `SE::EnvVarNotFoundAtRuntime`
- Name fields on `SE::ModuleNotFoundAtRuntime`
- Remove usused `ModuleOrOverlayNotFoundAtRuntime`
- Name fields on `SE::OverlayNotFoundAtRuntime`
- Name field on `SE::NotFound`
Continuation of #8229
# Description
The `ShellError` enum at the moment is kind of messy.
Many variants are basic tuple structs where you always have to reference
the implementation with its macro invocation to know which field serves
which purpose.
Furthermore we have both variants that are kind of redundant or either
overly broad to be useful for the user to match on or overly specific
with few uses.
So I set out to start fixing the lacking documentation and naming to
make it feasible to critically review the individual usages and fix
those.
Furthermore we can decide to join or split up variants that don't seem
to be fit for purpose.
**Everyone:** Feel free to add review comments if you spot inconsistent
use of `ShellError` variants.
- Name fields of `SE::IncorrectValue`
- Merge and name fields on `SE::TypeMismatch`
- Name fields on `SE::UnsupportedOperator`
- Name fields on `AssignmentRequires*` and fix doc
- Name fields on `SE::UnknownOperator`
- Name fields on `SE::MissingParameter`
- Name fields on `SE::DelimiterError`
- Name fields on `SE::IncompatibleParametersSingle`
# User-Facing Changes
(None now, end goal more explicit and consistent error messages)
# Tests + Formatting
(No additional tests needed so far)
# Description
Adds a `profile` command that profiles each pipeline element of a block
and can also recursively step into child blocks.
# Limitations
* It is implemented using pipeline metadata which currently get lost in
some circumstances (e.g.,
https://github.com/nushell/nushell/issues/4501). This means that the
profiler will lose data coming from subexpressions. This issue will
hopefully be solved in the future.
* It also does not step into individual loop iteration which I'm not
sure why but maybe that's a good thing.
# User-Facing Changes
Shouldn't change any existing behavior.
# 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
# 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.
---------
Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>
# Description
Fixes: #7828
We delegate to `save` command to finish redirection, then if it runs to
success, the relative exit code is set to 0. To fix it, in redirection
context, we take exit_code stream before sending it to `save` command,
than manually returns `PipelineData::ExternalStream` to make nushell set
relative code properly.
# User-Facing Changes
_(List of all changes that impact the user experience here. This helps
us keep track of breaking changes.)_
# 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
# 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
Lint: `clippy::uninlined_format_args`
More readable in most situations.
(May be slightly confusing for modifier format strings
https://doc.rust-lang.org/std/fmt/index.html#formatting-parameters)
Alternative to #7865
# User-Facing Changes
None intended
# Tests + Formatting
(Ran `cargo +stable clippy --fix --workspace -- -A clippy::all -D
clippy::uninlined_format_args` to achieve this. Depends on Rust `1.67`)
This is an attempt to implement a new `Value::LazyRecord` variant for
performance reasons.
`LazyRecord` is like a regular `Record`, but it's possible to access
individual columns without evaluating other columns. I've implemented
`LazyRecord` for the special `$nu` variable; accessing `$nu` is
relatively slow because of all the information in `scope`, and [`$nu`
accounts for about 2/3 of Nu's startup time on
Linux](https://github.com/nushell/nushell/issues/6677#issuecomment-1364618122).
### Benchmarks
I ran some benchmarks on my desktop (Linux, 12900K) and the results are
very pleasing.
Nu's time to start up and run a command (`cargo build --release;
hyperfine 'target/release/nu -c "echo \"Hello, world!\""' --shell=none
--warmup 10`) goes from **8.8ms to 3.2ms, about 2.8x faster**.
Tests are also much faster! Running `cargo nextest` (with our very slow
`proptest` tests disabled) goes from **7.2s to 4.4s (1.6x faster)**,
because most tests involve launching a new instance of Nu.
### Design (updated)
I've added a new `LazyRecord` trait and added a `Value` variant wrapping
those trait objects, much like `CustomValue`. `LazyRecord`
implementations must implement these 2 functions:
```rust
// All column names
fn column_names(&self) -> Vec<&'static str>;
// Get 1 specific column value
fn get_column_value(&self, column: &str) -> Result<Value, ShellError>;
```
### Serializability
`Value` variants must implement `Serializable` and `Deserializable`, which poses some problems because I want to use unserializable things like `EngineState` in `LazyRecord`s. To work around this, I basically lie to the type system:
1. Add `#[typetag::serde(tag = "type")]` to `LazyRecord` to make it serializable
2. Any unserializable fields in `LazyRecord` implementations get marked with `#[serde(skip)]`
3. At the point where a `LazyRecord` normally would get serialized and sent to a plugin, I instead collect it into a regular `Value::Record` (which can be serialized)
Add recursion limit to `def` and `block`.
Summary of this PR , it will detect if `def` call itself or not .
Then execute by using `stack` which I think best choice to use with this
design and core as it is available in all crates and mutable and
calculate the recursion limit on calling `def`.
Set 50 as recursion limit on `Config`.
Add some tests too .
Fixes#5899
Co-authored-by: Reilly Wood <reilly.wood@icloud.com>
# Description
This closes#7498, as well as fixes an issue reported in
https://github.com/nushell/nushell/pull/7002#issuecomment-1368340773
BEFORE:
```
〉[{foo: 'bar'} {}] | get foo
Error: nu:🐚:column_not_found (link)
× Cannot find column
╭─[entry #5:1:1]
1 │ [{foo: 'bar'} {}] | get foo
· ────────┬──────── ─┬─
· │ ╰── value originates here
· ╰── cannot find column 'Empty cell'
╰────
〉[{foo: 'bar'} {}].foo
╭───┬─────╮
│ 0 │ bar │
│ 1 │ │
╰───┴─────╯
```
AFTER:
```
〉[{foo: 'bar'} {}] | get foo
Error: nu:🐚:column_not_found (link)
× Cannot find column
╭─[entry #1:1:1]
1 │ [{foo: 'bar'} {}] | get foo
· ─┬ ─┬─
· │ ╰── cannot find column 'foo'
· ╰── value originates here
╰────
〉[{foo: 'bar'} {}].foo
Error: nu:🐚:column_not_found (link)
× Cannot find column
╭─[entry #3:1:1]
1 │ [{foo: 'bar'} {}].foo
· ─┬ ─┬─
· │ ╰── cannot find column 'foo'
· ╰── value originates here
╰────
```
EDIT: This also changes the semantics of `get`/`select` `-i` somewhat.
I've decided to leave it like this because it works more intuitively
with `default` and `compact`.
BEFORE:
```
〉[{a:1} {b:2} {a:3}] | select -i foo | to nuon
null
```
AFTER:
```
〉[{a:1} {b:2} {a:3}] | select -i foo | to nuon
[[foo]; [null], [null], [null]]
```
# User-Facing Changes
See above. EDIT: the issue with holes in cases like ` [{foo: 'bar'}
{}].foo.0` versus ` [{foo: 'bar'} {}].0.foo` has been resolved.
# 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
# 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.
Closes#7572 by adding a cache for compiled regexes of type
`Arc<Mutex<LruCache<String, Regex>>>` to `EngineState` .
The cache is limited to 100 entries (limit chosen arbitrarily) and
evicts least-recently-used items first.
This PR makes a noticeable difference when using regexes for
`color_config`, e.g.:
```bash
#first set string formatting in config.nu like:
string: { if $in =~ '^#\w{6}$' { $in } else { 'white' } }`
# then try displaying and exploring a table with many strings
# this is instant after the PR, but takes hundreds of milliseconds before
['#ff0033', '#0025ee', '#0087aa', 'string', '#4101ff', '#ff0033', '#0025ee', '#0087aa', 'string', '#6103ff', '#ff0033', '#0025ee', '#0087aa', 'string', '#6103ff', '#ff0033', '#0025ee', '#0087aa', 'string', '#6103ff', '#ff0033', '#0025ee', '#0087aa', 'string', '#6103ff','#ff0033', '#0025ee', '#0087aa', 'string', '#6103ff','#ff0033', '#0025ee', '#0087aa', 'string', '#6103ff','#ff0033', '#0025ee', '#0087aa', 'string', '#6103ff','#ff0033', '#0025ee', '#0087aa', 'string', '#6103ff','#ff0033', '#0025ee', '#0087aa', 'string', '#6103ff']
```
## New dependency (`lru`)
This uses [the popular `lru` crate](https://lib.rs/crates/lru). The new
dependency adds 19.8KB to a Linux release build of Nushell. I think this
is OK, especially since the crate can be useful elsewhere in Nu.
I've been working on streaming and pipeline interruption lately. It was
bothering me that checking ctrl+c (something we want to do often) always
requires a bunch of boilerplate like:
```rust
use std::sync::atomic::Ordering;
if let Some(ctrlc) = &engine_state.ctrlc {
if ctrlc.load(Ordering::SeqCst) {
...
```
I added a helper method to cut that down to:
```rust
if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
...
```
# Description
Just spot that there are some duplicate code about checking external
runs to failed, is pr is trying to refactor it and reduce lines of code
# User-Facing Changes
NaN
# 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
# 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.
Reverts nushell/nushell#7448
Some surprising behavior in how we do this. For example:
```
〉if (true || false) { print "yes!" } else { print "no!" }
no!
〉if (true or false) { print "yes!" } else { print "no!" }
yes!
```
This means for folks who are using the old `||`, they possibly get the
wrong answer once they upgrade. I don't think we can ship with that as
it will catch too many people by surprise and just make it easier to
write buggy code.
# Description
We got some feedback from folks used to other shells that `try/catch`
isn't quite as convenient as things like `||`. This PR adds `&&` as a
synonym for `;` and `||` as equivalent to what `try/catch` would do.
# User-Facing Changes
Adds `&&` and `||` pipeline operators.
# 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
# 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
While perusing Value.rs, I noticed the `Value::int()`, `Value::float()`,
`Value::boolean()` and `Value::string()` constructors, which seem
designed to make it easier to construct various Values, but which aren't
used often at all in the codebase. So, using a few find-replaces
regexes, I increased their usage. This reduces overall LOC because
structures like this:
```
Value::Int {
val: a,
span: head
}
```
are changed into
```
Value::int(a, head)
```
and are respected as such by the project's formatter.
There are little readability concerns because the second argument to all
of these is `span`, and it's almost always extremely obvious which is
the span at every callsite.
# User-Facing Changes
None.
# 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
# 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 fix changes pipelines to allow them to actually be empty. Mapping
over empty pipelines gives empty pipelines. Empty pipelines immediately
return `None` when iterated.
This removes a some of where `Span::new(0, 0)` was coming from, though
there are other cases where we still use it.
# User-Facing Changes
None
# 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
# 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
Closes#7110. ~~Note that unlike "real" `mut` vars, $env can be deeply
mutated via stuff like `$env.PYTHON_IO_ENCODING = utf8` or
`$env.config.history.max_size = 2000`. So, it's a slightly awkward
special case, arguably justifiable because of what $env represents (the
environment variables of your system, which is essentially "outside"
normal Nushell regulations).~~
EDIT: Now allows all `mut` vars to be deeply mutated using `=`, on
request.
# 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
# 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.
Also enforce this by #[non_exhaustive] span such that going forward we
cannot, in debug builds (1), construct invalid spans.
The motivation for this stems from #6431 where I've seen crashes due to
invalid slice indexing.
My hope is this will mitigate such senarios
1. https://github.com/nushell/nushell/pull/6431#issuecomment-1278147241
# Description
(description of your pull request here)
# Tests
Make sure you've done the following:
- [ ] Add tests that cover your changes, either in the command examples,
the crate/tests folder, or in the /tests folder.
- [ ] Try to think about corner cases and various ways how your changes
could break. Cover them with tests.
- [ ] If adding tests is not possible, please document in the PR body a
minimal example with steps on how to reproduce so one can verify your
change works.
Make sure you've run and fixed any issues with these commands:
- [x] `cargo fmt --all -- --check` to check standard code formatting
(`cargo fmt --all` applies these changes)
- [ ] `cargo clippy --workspace --features=extra -- -D warnings -D
clippy::unwrap_used -A clippy::needless_collect` to check that you're
using the standard code style
- [ ] `cargo test --workspace --features=extra` to check that all the
tests pass
# Documentation
- [ ] If your PR touches a user-facing nushell feature then make sure
that there is an entry in the documentation
(https://github.com/nushell/nushell.github.io) for the feature, and
update it if necessary.
# Description
Closes: #6920
# User-Facing Changes
```
❯ "asdf" | save dump.rdb
Error:
× Destination file already exists
╭─[entry #21:1:1]
1 │ "asdf" | save dump.rdb
· ────┬───
· ╰── Destination file '/tmp/dump.rdb' already exists
╰────
help: you can use -f, --force to force overwriting the destination
```
# 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
# 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.
We already have the binary `bit-xor` and the shortcircuiting logical
`or`(`||`) and `and`(`&&`).
This introduces `xor` as a compact form for both brevity and clarity.
You can express the operation through `not`/`and`/`or` with a slight
risk of introducing bugs through typos.
Operator precedence
`and` > `xor` > `or`
Added logic and precedence tests.
# Description
This adds `break`, `continue`, `return`, and `loop`.
* `break` - breaks out a loop
* `continue` - continues a loop at the next iteration
* `return` - early return from a function call
* `loop` - loop forever (until the loop hits a break)
Examples:
```
for i in 1..10 {
if $i == 5 {
continue
}
print $i
}
```
```
for i in 1..10 {
if $i == 5 {
break
}
print $i
}
```
```
def foo [x] {
if true {
return 2
}
$x
}
foo 100
```
```
loop { print "hello, forever" }
```
```
[1, 2, 3, 4, 5] | each {|x|
if $x > 3 { break }
$x
}
```
# User-Facing Changes
Adds the above commands.
# 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
# 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 is a set of fixes to `err>` to make it work a bit more predictably.
I've also revised the tests, which accidentally tested the wrong thing
for redirection, but should be more correct now.
# User-Facing Changes
_(List of all changes that impact the user experience here. This helps
us keep track of breaking changes.)_
# 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
# 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
As title, when execute external sub command, auto-trimming end
new-lines, like how fish shell does.
And if the command is executed directly like: `cat tmp`, the result
won't change.
Fixes: #6816Fixes: #3980
Note that although nushell works correctly by directly replace output of
external command to variable(or other places like string interpolation),
it's not friendly to user, and users almost want to use `str trim` to
trim trailing newline, I think that's why fish shell do this
automatically.
If the pr is ok, as a result, no more `str trim -r` is required when
user is writing scripts which using external commands.
# User-Facing Changes
Before:
<img width="523" alt="img"
src="https://user-images.githubusercontent.com/22256154/202468810-86b04dbb-c147-459a-96a5-e0095eeaab3d.png">
After:
<img width="505" alt="img"
src="https://user-images.githubusercontent.com/22256154/202468599-7b537488-3d6b-458e-9d75-d85780826db0.png">
# 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 --features=extra -- -D warnings -D
clippy::unwrap_used -A clippy::needless_collect` to check that you're
using the standard code style
- `cargo test --workspace --features=extra` to check that all tests pass
# 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
Spotted by @WindSoilder - don't redirect stdout if the user requests
`err>`.
# User-Facing Changes
_(List of all changes that impact the user experience here. This helps
us keep track of breaking changes.)_
# 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
# 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.
This adds new pipeline connectors called out> and err> which redirect either stdout or stderr to a file. You can also use out+err> (or err+out>) to redirect both streams into a file.
* add signature information when help on one command
* tell user that one command support operated on cell paths
Also, make type output to be more friendly, like `record<>` should just be `record`
And the same to `table<>`, which should be `table`
* simplify code
* don't show signatures for parser keyword
* update comment
* output arg syntax shape as type, so it's the same as describe command
* fix string when no positional args
* update signature body
* update
* add help signature test
* fix arg output format for composed data type like list or record
* fix clippy
* add comment
This adds support for (limited) mutable variables. Mutable variables are created with mut much the same way immutable variables are made with let.
Mutable variables allow mutation via the assignment operator (=).
❯ mut x = 100
❯ $x = 200
❯ print $x
200
Mutable variables are limited in that they're only tended to be used in the local code block. Trying to capture a local variable will result in an error:
❯ mut x = 123; {|| $x }
Error: nu::parser::expected_keyword (link)
× Capture of mutable variable.
The intent of this limitation is to reduce some of the issues with mutable variables in general: namely they make code that's harder to reason about. By reducing the scope that a mutable variable can be used it, we can help create local reasoning about them.
Mutation can occur with fields as well, as in this case:
❯ mut y = {abc: 123}
❯ $y.abc = 456
❯ $y
On a historical note: mutable variables are something that we resisted for quite a long time, leaning as much as we could on the functional style of pipelines and dataflow. That said, we've watched folks struggle to work with reduce as an approximation for patterns that would be trivial to express with local mutation. With that in mind, we're leaning towards the happy path.
