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 unnecessary `#[allow]` annots
Reduce the number of lint exceptions that are not necessary with the
current state of the code (or more recent toolchain)
* Remove dead code from `FileStructure` in nu-command
* Replace `allow(unused)` with relevant feature switch
* Deal with `needless_collect` with annotations
* Change hack for needless_collect in `from json`
This change obviates the need for `allow(needless_collect)`
Removes a pessimistic allocation for empty strings, but increases
allocation size to `Value`
Probably not really worth it.
* Revert "Deal with `needless_collect` with annotations"
This reverts commit 05aca98445.
The previous state seems to better from a performance perspective as a
`Vec<String>` is lighter weight than `Vec<Value>`
* 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>
* Add source-env test for dynamic path
* Use correct module ID for env overlay imports
* Remove parser check from "overlay list"
It would cause unnecessary errors from some inner scope if some
overlay module was also defined in some inner scope.
* Restore Cargo.lock back
* Remove comments
* start working on source-env
* WIP
* Get most tests working, still one to go
* Fix file-relative paths; Report parser error
* Fix merge conflicts; Restore source as deprecated
* Tests: Use source-env; Remove redundant tests
* Fmt
* Respect hidden env vars
* Fix file-relative eval for source-env
* Add file-relative eval to "overlay use"
* Use FILE_PWD only in source-env and "overlay use"
* Ignore new tests for now
This will be another issue
* Throw an error if setting FILE_PWD manually
* Fix source-related test failures
* Fix nu-check to respect FILE_PWD
* Fix corrupted spans in source-env shell errors
* Fix up some references to old source
* Remove deprecation message
* Re-introduce deleted tests
Co-authored-by: kubouch <kubouch@gmail.com>
* when spawned process during register plugin, pass env to child process
* tweak comment
* tweak comment
* remove trailing whitespace
Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>
* Allow private imports inside modules
Can call `use ...` inside modules now.
* Add more tests
* Add a leak test
* Refactor exportables; Prepare for 'export use'
* Fix description
* Implement 'export use' command
This allows re-exporting module's commands and aliases from another
module.
* Add more tests; Fix import pattern list strings
The import pattern strings didn't trim the surrounding quotes.
* Add ignored test
* expand durations to include month, year, decade
* remove commented out fn
* oops, found more debug comments
* tweaked tests for the new way, borrowed heavily from chrono-humanize-rs
* clippy
* grammar
* Fix 5978
* Add unit test for explicit glob
* Format
* Expansion vs none-expansion
* Add unit tests
* Fix format..
* Add debug message for MacOS
* Fix UT on Mac and add tests for windows
* cleanup
* clean up windows test
* single and double qoutes tests
* format...
* Save format.
* Add log to failed windows unit tests
* try `touch` a file
* PS or CMD
* roll back some change
* format
* Remove log and test case
* Add unit test comments
* Fix
Co-authored-by: Frank <v-frankz@microsoft.com>
