# Description
We were seeing duplicate entries for the std lib files, and this PR
addresses that. Each file should now only be added once.
Note: they are still parsed twice because it's hard to recover the
module from the output of `parse` but a bit of clever hacking in a
future PR might be able to do that.
# 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
- `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.
# Description
this pr allows `register` to be used with const variables
```nu
const math_plugin = "~/.config/nushell/plugins/nu_plugin_math"
register $math_plugin
```
should close#8208, previous work #8435
related to #8765.
should close#8812.
# Description
this PR simply removes the `prinln("MODULE NOT FOUND")` from the parser.
# User-Facing Changes
no more `MODULE NOT FOUND` while typing a `use` command
# 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
This is an experiment to see what switching the `let/let-env` family to
math expressions for initialisers would be like.
# User-Facing Changes
This would require any commands you call from `let x = <command here>`
(and similar family) to call the command in parentheses. `let x = (foo)`
to call `foo`.
# 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
Fixes: #8548
# User-Facing Changes
```
❯ register target/debug/formats
Error:
× Register plugin failed
╭─[entry #1:1:1]
1 │ register target/debug/formats
· ──────────┬─────────
· ╰── plugin name must starts with nu_plugin_
╰────
```
# 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.
Reverts nushell/nushell#8310
In anticipation that we may want to revert this PR. I'm starting the
process because of this issue.
This stopped working
```
let-env NU_LIB_DIRS = [
($nu.config-path | path dirname | path join 'scripts')
'C:\Users\username\source\repos\forks\nu_scripts'
($nu.config-path | path dirname)
]
```
You have to do this now instead.
```
const NU_LIB_DIRS = [
'C:\Users\username\AppData\Roaming\nushell\scripts'
'C:\Users\username\source\repos\forks\nu_scripts'
'C:\Users\username\AppData\Roaming\nushell'
]
```
In talking with @kubouch, he was saying that the `let-env` version
should keep working. Hopefully it's a small change.
# Description
Allow NU_LIBS_DIR and friends to be const they can be updated within the
same parse pass. This will allow us to remove having multiple config
files eventually.
Small implementation detail: I've changed `call.parser_info` to a
hashmap with string keys, so the information can have names rather than
indices, and we don't have to worry too much about the order in which we
put things into it.
Closes https://github.com/nushell/nushell/issues/8422
# User-Facing Changes
In a single file, users can now do stuff like
```
const NU_LIBS_DIR = ['/some/path/here']
source script.nu
```
and the source statement will use the value of NU_LIBS_DIR declared the
line before.
Currently, if there is no `NU_LIBS_DIR` const, then we fallback to using
the value of the `NU_LIBS_DIR` env-var, so there are no breaking changes
(unless someone named a const NU_LIBS_DIR for some reason).
# Tests + Formatting
~~TODO: write tests~~ Done
# After Submitting
~~TODO: update docs~~ Will do when we update default_env.nu/merge
default_env.nu into default_config.nu.
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
Prevents alias from aliasing itself. It allows a commonly requested
pattern similar to `alias ls = ls -l`.
One small issue is that the syntax highlighting is a bit off:
Fixes https://github.com/nushell/nushell/issues/8246
# User-Facing Changes
Shouldn't be a breaking change.
# 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 PR adds an alternative alias implementation. Old aliases still work
but you need to use `old-alias` instead of `alias`.
Instead of replacing spans in the original code and re-parsing, which
proved to be extremely error-prone and a constant source of panics, the
new implementation creates a new command that references the old
command. Consider the new alias defined as `alias ll = ls -l`. The
parser creates a new command called `ll` and remembers that it is
actually a `ls` command called with the `-l` flag. Then, when the parser
sees the `ll` command, it will translate it to `ls -l` and passes to it
any parameters that were passed to the call to `ll`. It works quite
similar to how known externals defined with `extern` are implemented.
The new alias implementation should work the same way as the old
aliases, including exporting from modules, referencing both known and
unknown externals. It seems to preserve custom completions and pipeline
metadata. It is quite robust in most cases but there are some rough
edges (see later).
Fixes https://github.com/nushell/nushell/issues/7648,
https://github.com/nushell/nushell/issues/8026,
https://github.com/nushell/nushell/issues/7512,
https://github.com/nushell/nushell/issues/5780,
https://github.com/nushell/nushell/issues/7754
No effect: https://github.com/nushell/nushell/issues/8122 (we might
revisit the completions code after this PR)
Should use custom command instead:
https://github.com/nushell/nushell/issues/6048
# User-Facing Changes
Since aliases are now basically commands, it has some new implications:
1. `alias spam = "spam"` (requires command call)
* **workaround**: use `alias spam = echo "spam"`
2. `def foo [] { 'foo' }; alias foo = ls -l` (foo defined more than
once)
* **workaround**: use different name (commands also have this
limitation)
4. `alias ls = (ls | sort-by type name -i)`
* **workaround**: Use custom command. _The common issue with this is
that it is currently not easy to pass flags through custom commands and
command referencing itself will lead to stack overflow. Both of these
issues are meant to be addressed._
5. TODO: Help messages, `which` command, `$nu.scope.aliases`, etc.
* Should we treat the aliases as commands or should they be separated
from regular commands?
6. Needs better error message and syntax highlight for recursed alias
(`alias f = f`)
7. Can't create alias with the same name as existing command (`alias ls
= ls -a`)
* Might be possible to add support for it (not 100% sure)
8. Standalone `alias` doesn't list aliases anymore
9. Can't alias parser keywords (e.g., stuff like `alias ou = overlay
use` won't work)
* TODO: Needs a better error message when attempting to do so
# 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, we can't provide examples for plugin commands, this pr would
make it possible
# User-Facing Changes
Take plugin `nu-example-1` as example:
```
❯ nu-example-1 -h
PluginSignature test 1 for plugin. Returns Value::Nothing
Usage:
> nu-example-1 {flags} <a> <b> (opt) ...(rest)
Flags:
-h, --help - Display the help message for this command
-f, --flag - a flag for the signature
-n, --named <String> - named string
Parameters:
a <int>: required integer value
b <string>: required string value
(optional) opt <int>: Optional number
...rest <string>: rest value string
Examples:
running example with an int value and string value
> nu-example-1 3 bb
```
The examples session is newly added.
## Basic idea behind these changes
when nushell query plugin signatures, plugin just returns it's signature
without any examples, so nushell have no idea about the examples of
plugin commands.
To adding the feature, we just making plugin returns it's signature with
examples.
Before:
```
1. get signature
---------------->
Nushell ------------------ Plugin
<-----------------
2. returns Vec<Signature>
```
After:
```
1. get signature
---------------->
Nushell ------------------ Plugin
<-----------------
2. returns Vec<PluginSignature>
```
When writing plugin signature to $nu.plugin-path:
Serialize `<PluginSignature>` rather than `<Signature>`, which would
enable us to serialize examples to `$nu.plugin-path`
## Shortcoming
It's a breaking changes because `Plugin::signature` is changed, and it
requires plugin authors to change their code for new signatures.
Fortunally it should be easy to change, for rust based plugin, we just
need to make a global replace from word `Signature` to word
`PluginSignature` in their plugin project.
Our content of plugin-path is really large, if one plugin have many
examples, it'd results to larger body of $nu.plugin-path, which is not
really scale. A solution would be save register information in other
binary formats rather than `json`. But I think it'd be another story.
# 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`)
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
Closes#7273.
Also slightly edits/tidies up parser.rs.
# User-Facing Changes
`^` is now forbidden in `def` and `def-env` command names. EDIT: also
`alias`.
# 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
Prevent a situation where a `def` can't be run due to a poor choice of
name. Related: #6335. Hashtags, numbers and filesizes are no longer
allowed. `alias` check has been moved because previously `alias 123`
would be caught but `alias "123"` would be permitted.
# User-Facing Changes
Some definitions can no longer be made, but because they couldn't be run
previously anyway, it doesn't really matter.
# 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
This PR moves the `where` command to a parser keyword. While it still
uses the shape-directed parsing dictated by the signature, we're free to
change the parsing code now to a custom one once we remove the syntax
shapes.
As a side effect, the `where -b` flag was removed and its functionality
has moved to the new `filter` command.
Just FYI, other commands that take row conditions:
- `take until`
- `take while`
- `skip until`
- `skip while`
- `any`
- `all`
We can either move these to the parser as well or make them accept a
closure instead of row condition.
# User-Facing Changes
New `filter` command which replaces `where -b` functionality.
# 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
This PR is a response to the issues raised in
https://github.com/nushell/nushell/pull/7087. It consists of two
changes:
* `export-env`, when evaluated in `overlay use`, will see the original
environment. Previously, it would see the environment from previous
overlay activation.
* Added a new `--reload` flag that reloads the overlay. Custom
definitions will be kept but the original definitions and environment
will be reloaded.
This enables a pattern when an overlay is supposed to shadow an existing
environment variable, such as `PROMPT_COMMAND`, but `overlay use` would
keep loading the value from the first activation. You can easily test it
by defining a module
```
module prompt {
export-env {
let-env PROMPT_COMMAND = (date now | into string)
}
}
```
Calling `overlay use prompt` for the first time changes the prompt to
the current time, however, subsequent calls of `overlay use` won't
change the time. That's because overlays, once activated, store their
state so they can be hidden and restored at later time. To force-reload
the environment, use the new flag: Calling `overlay use --reload prompt`
repeatedly now updates the prompt with the current time each time.
# User-Facing Changes
* When calling `overlay use`, if the module has an `export-env` block,
the block will see the environment as it is _before_ the overlay is
activated. Previously, it was _after_.
* A new `overlay use --reload` flag.
# 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
Since we're not implementing `&&` or `||`, let's remove their pipeline
elements.
# User-Facing Changes
Nothing user facing. These were not yet implemented.
# 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
rust 1.65.0 has been released for a while, this pr applies lint
suggestions from rust 1.65.0.
# User-Facing Changes
N/A
# 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.
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.
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.
* remove export_env command
* remove several export env usage in test code
* adjust hiding relative test case
* fix clippy
* adjust tests
* update tests
* unignore these tests to expose ut failed
* using `use` instead of `overlay use` in some tests
* Revert "using `use` instead of `overlay use` in some tests"
This reverts commit 2ae24b24c3.
* Revert "adjust hiding relative test case"
This reverts commit 4369af6d05.
* Bring back module example
* Revert "update tests"
This reverts commit 6ae94ef513.
* Fix tests
* "Fix" a test
* Remove remaining deprecated env functionality
* Re-enable environment hiding for `hide`
To not break virtualenv since the overlay update is not merged yet
* Fix hiding env in `hide` and ignore some tests
Co-authored-by: kubouch <kubouch@gmail.com>
