feat: nargo command to generate shell completions (#6413)

cspell.json

@@ -14,6 +14,7 @@
         "arithmetization",
         "arity",
         "arkworks",
+        "autoload",
         "backpropagate",
         "Backpropagation",
         "barebones",
@@ -51,6 +52,7 @@
         "codespan",
         "coeff",
         "combinators",
+        "compinit",
         "comptime",
         "cpus",
         "cranelift",
@@ -91,6 +93,7 @@
         "forall",
         "foralls",
         "formatcp",
+        "fpath",
         "frontends",
         "fuzzer",
         "fxhash",

docs/docs/getting_started/noir_installation.md

@@ -91,6 +91,10 @@ Step 1: Follow the instructions [here](https://learn.microsoft.com/en-us/windows
 
 step 2: Follow the [Noirup instructions](#installing-noirup).
 
+## Setting up shell completions
+
+Once `nargo` is installed, you can [set up shell completions for it](setting_up_shell_completions).
+
 ## Uninstalling Nargo
 
 If you installed Nargo with `noirup`, you can uninstall Nargo by removing the files in `~/.nargo`, `~/nargo`, and `~/noir_cache`. This ensures that all installed binaries, configurations, and cache related to Nargo are fully removed from your system.

docs/docs/getting_started/quick_start.md

@@ -17,6 +17,8 @@ curl -L noirup.dev | bash
 noirup
 ```
 
+Once installed, you can [set up shell completions for the `nargo` command](setting_up_shell_completions).
+
 ### Proving backend
 
 After installing Noir, we install a proving backend to work with our Noir programs.

docs/docs/getting_started/setting_up_shell_completions.md

@@ -0,0 +1,87 @@
+---
+title: Setting up shell completions
+tags: []
+sidebar_position: 3
+---
+
+The `nargo` binary provides a command to generate shell completions:
+
+```bash
+nargo generate-completion-script [shell]
+```
+
+where `shell` must be one of `bash`, `elvish`, `fish`, `powershell`, and `zsh`.
+
+Below we explain how to install them in some popular shells.
+
+## Installing Zsh Completions
+
+If you have `oh-my-zsh` installed, you might already have a directory of automatically loading completion scripts — `.oh-my-zsh/completions`.
+If not, first create it:
+
+```bash
+mkdir -p ~/.oh-my-zsh/completions`
+```
+
+Then copy the completion script to that directory:
+
+```bash
+nargo generate-completion-script zsh > ~/.oh-my-zsh/completions/_nargo
+```
+
+Without `oh-my-zsh`, you’ll need to add a path for completion scripts to your function path, and turn on completion script auto-loading. 
+First, add these lines to `~/.zshrc`:
+
+```bash
+fpath=(~/.zsh/completions $fpath)
+autoload -U compinit
+compinit
+```
+
+Next, create a directory at `~/.zsh/completions`:
+
+```bash
+mkdir -p ~/.zsh/completions
+```
+
+Then copy the completion script to that directory:
+
+```bash
+nargo generate-completion-script zsh > ~/.zsh/completions/_nargo
+```
+
+## Installing Bash Completions
+
+If you have [bash-completion](https://github.com/scop/bash-completion) installed, you can just copy the completion script to the `/usr/local/etc/bash_completion.d` directory:
+
+```bash
+nargo generate-completion-script bash > /usr/local/etc/bash_completion.d/nargo
+```
+
+Without `bash-completion`, you’ll need to source the completion script directly. 
+First create a directory such as `~/.bash_completions/`:
+
+```bash
+mkdir ~/.bash_completions/
+```
+
+Copy the completion script to that directory:
+
+```bash
+nargo generate-completion-script bash > ~/.bash_completions/nargo.bash
+```
+
+Then add the following line to `~/.bash_profile` or `~/.bashrc`:
+
+
+```bash
+source ~/.bash_completions/nargo.bash
+```
+
+## Installing Fish Completions
+
+Copy the completion script to any path listed in the environment variable `$fish_completion_path`. For example, a typical location is `~/.config/fish/completions/nargo.fish`:
+
+```bash
+nargo generate-completion-script fish > ~/.config/fish/completions/nargo.fish
+```

tooling/nargo_cli/Cargo.toml

@@ -66,6 +66,7 @@ termion = "3.0.0"
 # Logs
 tracing-subscriber.workspace = true
 tracing-appender = "0.2.3"
+clap_complete = "4.5.36"
 
 [target.'cfg(not(unix))'.dependencies]
 tokio-util = { version = "0.7.8", features = ["compat"] }

tooling/nargo_cli/src/cli/generate_completion_script_cmd.rs

@@ -0,0 +1,33 @@
+use clap::{Args, CommandFactory};
+use clap_complete::Shell;
+
+use crate::errors::CliError;
+
+use super::NargoCli;
+
+/// Generates a shell completion script for your favorite shell
+#[derive(Debug, Clone, Args)]
+pub(crate) struct GenerateCompletionScriptCommand {
+    /// The shell to generate completions for. One of: bash, elvish, fish, powershell, zsh
+    pub(crate) shell: String,
+}
+
+pub(crate) fn run(command: GenerateCompletionScriptCommand) -> Result<(), CliError> {
+    let shell = match command.shell.to_lowercase().as_str() {
+        "bash" => Shell::Bash,
+        "elvish" => Shell::Elvish,
+        "fish" => Shell::Fish,
+        "powershell" => Shell::PowerShell,
+        "zsh" => Shell::Zsh,
+        _ => {
+            return Err(CliError::Generic(
+                "Invalid shell. Supported shells are: bash, elvish, fish, powershell, zsh"
+                    .to_string(),
+            ))
+        }
+    };
+
+    clap_complete::generate(shell, &mut NargoCli::command(), "nargo", &mut std::io::stdout());
+
+    Ok(())
+}