Generating Shell Completions for rustup and cargo (with examples)

Motivation:

When working with the Rust programming language, it is often helpful to have shell completions for the rustup and cargo commands. Shell completions provide suggestions and autocompletion for command line arguments, making it easier and faster to type commands accurately and efficiently. By generating shell completions for rustup and cargo, developers can enhance their productivity and reduce errors while interacting with the Rust toolchain.

1. Generating Bash Completion Script

Code:

rustup completions bash rustup cargo

Explanation:

The rustup completions command generates the shell completion script for the specified shell (in this case, bash) and the provided commands (rustup and cargo). The completion script for bash will be printed to the standard output (stdout).

Example Output:

# Rustup Bash completion
function _rustup_completion() {
  local commands global_opts opts
  commands="toolchain override alias run which completions update show default install uninstall list update check search doc man self run completions help"
  global_opts="--color always --quiet --no-self-update --offline --verbose"
  opts="--help --verbose --quiet --color auto --color always --color never --force --no-pager --version"
  COMPREPLY=()
  local cur="${COMP_WORDS[COMP_CWORD]}"
  local prev="${COMP_WORDS[COMP_CWORD-1]}"
  local bin="rustup"
  case "${prev}" in
    "toolchain"|""|"completions")
      COMPREPLY=( $(compgen -W "${commands}" -- ${cur}) )
      return 0
      ;;

2. Generating Elvish Completion Script

Code:

rustup completions elvish rustup cargo

Explanation:

The rustup completions command is used to generate shell completions for Elvish shell. By specifying the shell as elvish and providing the commands (rustup and cargo), the completion script for Elvish shell will be printed to the standard output (stdout).

Example Output:

~mod@mac ~/rust/rustup (master=)$ 
editor $

prompt:
▶ eve completion/rustup
Fn {|-path -cmd|} {
    put (comps lists: [~rustup ~cargo] $cmd)$paths
}

3. Generating Fish Completion Script

Code:

rustup completions fish rustup cargo

Explanation:

To generate shell completions for the fish shell, we use the rustup completions command with the fish argument followed by the commands rustup and cargo. The completion script for fish will be printed to the standard output (stdout).

Example Output:

# Rustup Fish completion
#
# To activate this completion, add the following to your
# `~/.config/fish/config.fish`:
#
#     rustup completions fish | source
#
# NOTE: Alternatively, you can also generate completions for rustup and the cargo command by following the same steps as above.
function __fish_rustup_using_project_root
  if test -z (command -v rustup)
    return 1
  end

  set -q _RU_YOG_SOURCE
  and test "$_RU_YOG_SOURCE" = "$PWD"

  return $status
end

function _metric_fu_using
end

4. Generating PowerShell Completion Script

Code:

rustup completions powershell rustup cargo

Explanation:

By running the rustup completions command with the powershell argument followed by the commands rustup and cargo, we can generate shell completions for the PowerShell environment. The completion script for PowerShell will be printed to the standard output (stdout).

Example Output:

# Rustup PowerShell completion
param(
  [Parameter(Position = 0, Mandatory = $True, ValueFromPipeline = $False)]
  [ValidateSet("cargo", "rustup")]
  [String]$CommandName,

  [Parameter(Position = 1)]
  [String]$BindingVariable,

  [Parameter(Position = 2)]
  [String]$StubSource
)

Set-StrictMode -Version Latest

if ($CommandName -eq "rustup") {
  ...
}
elseif ($CommandName -eq "cargo") {
  ...
}

5. Generating Zsh Completion Script

Code:

rustup completions zsh rustup cargo

Explanation:

To generate shell completions for the Zsh shell, we use the rustup completions command with the zsh argument followed by the commands rustup and cargo. The completion script for Zsh will be printed to the standard output (stdout).

Example Output:

#compdef rustup cargo

zstyle ':completion::complete:rustup::' use-cache 1
zstyle ':completion::complete:rustup::' cache-path $HOME/.cargo/tmp/.rustup-zcomps
zstyle ':completion::complete:rustup::' dispatcher breadth-first
zstyle ':completion::complete:rustup::' menu select

# Pre-command hook for validating Only-tags
__precommands_tags() {
  local -a commands
  if [[ ! -r "$XDG_CACHE_HOME/rustup/installed-tools" ]] {
    commands=("completions")
  }
  if [[ ( -n "$commands" ) ]]; then
    _wanted commands expl "${commands[@]}" compadd -a commands
  fi
}

_rustup() {
  local expl

  _arguments -C "1: :->subcmds" \
    "2: :->args" \
    "*:: :->args_rest" \

  local subcmds=(...long list of subcommands...)
  if [[ ( $state = subcmds ) ]]; then
    _wanted commands expl "Subcommand" compadd -a subcmds
  fi

  subcmds=(
    'show: :_rustup_show'
    ...
  )
  
  if [[ ( -n "$subcmds[(r)$words[1]]" ) ]]; then
    "$subcmds[(r)$words[1]]"
  fi
}

By utilizing the rustup completions command with different shell arguments, developers can generate shell completion scripts for rustup and cargo in their preferred shell environments. These completion scripts provide improved productivity and error-reduction while interacting with the Rust toolchain.