5bfec20244
## 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 |
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| README.md | ||
nu-cmd-lang
the base language and command crate of nu
The commands in this crate are the core commands of the nu language. It is also the base crate upon which all other command crates sit on top of including:
- nu-command
- nu-cli
- nu-cmd-dataframe
- nu-cmd-extra
As time goes on and the nu language develops further in parallel with nushell we will be adding other command crates to the system.
What does it mean to be a base crate ?
A base crate is one with minimal dependencies in our system so that other developers can come along and use this crate without having a lot of baggage in terms of other crates which will bloat their underlying application.
Background on nu-cmd-lang
This crate was designed to be a small, concise set of tools or commands that serve as the foundation layer of both nu and nushell. These are the core commands needed to have a nice working version of the nu language without all of the support that the other commands provide inside nushell. Prior to the launch of this crate all of our commands were housed in the crate nu-command. Moving forward we would like to slowly break out the commands in nu-command into different crates; the naming and how this will work and where all the commands will be located is a "work in progress" especially now that the standard library is starting to become more popular as a location for commands. As time goes on some of our commands written in rust will be migrated to nu and when this happens they will be moved into the standard library.