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.
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.
* attempts to add `div` math operator
* allows `//` to be used too
* fmt:
* clippy issue
* returns appropriate type
* returns appropriate type 2
* fmt
* ensure consistency; rename to `fdiv`
* Update parser.rs
