zsh: handle 'foo bar' == 'foo-bar' and latest

asdf now optionally allows git-style 'foo bar' sub-commands, so the
completion system should too.

Implement support for `asdf latest` and `asdf install foo latest`

completions/_asdf

@@ -6,14 +6,19 @@ local asdf_dir="${ASDF_DATA_DIR:-$HOME/.asdf}"
 
 local -a asdf_commands
 asdf_commands=( # 'asdf help' lists commands with help text
+  # plugins
+  'plugin:plugin management sub-commands'
   'plugin-add:add plugin from asdf-plugins repo or from git URL'
   'plugin-list:list installed plugins (--url with URLs)'
   'plugin-list-all:list all plugins registered in asdf-plugins repo'
   'plugin-remove:remove named plugin and all packages for it'
   'plugin-update:update named plugin (or --all)'
+
+  # packages
   'install:install plugin at stated version, or all from .tools-versions'
   'uninstall:remove a specific version of a package'
   'current:display current versions for named package (else all)'
+  'latest:display latest version available to install for a named package'
   'where:display install path for given package at optional specified version'
   'which:display path to an executable'
   'shell:via env vars, set package to version in current shell'
@@ -21,9 +26,12 @@ asdf_commands=( # 'asdf help' lists commands with help text
   'global:set package global version'
   'list:list installed versions of a package'
   'list-all:list all available (remote) versions of a package'
+
+  # utils
   'exec:executes the command shim for the current version'
   'env:prints or runs an executable under a command environment'
   'reshim:recreate shims for version of a package'
+  'shim:shim management sub-commands'
   'shim-versions:list for given command which plugins and versions provide it'
   'update:update ASDF to the latest stable release (unless --head)'
 )
@@ -67,6 +75,8 @@ _asdf__installed_versions_of() {
     compadd -a versions
 }
 
+local -i IntermediateCount=0
+
 if (( CURRENT == 2 )); then
   _arguments -C : '--version[version]' ':command:->command'
 fi
@@ -80,33 +90,78 @@ esac
 subcmd="${words[2]}"
 curcontext="${curcontext%:*}=$subcmd:"
 
+# Handle 'foo bar' == 'foo-bar'
+_asdf__dash_commands() {
+  if (( CURRENT == 3 + IntermediateCount )); then
+    local -a sub_commands
+    sub_commands=(${${(M)asdf_commands:#${subcmd}-*}#${subcmd}-})
+    _describe -t asdf-commands 'ASDF Commands' sub_commands
+  else
+    IntermediateCount+=1
+    subcmd="${subcmd}-${words[2+IntermediateCount]}"
+  fi
+}
+case "$subcmd" in
+(plugin|shim|list)
+  _asdf__dash_commands
+  ;;
+esac
+case "$subcmd" in
+(plugin-list)
+  _asdf__dash_commands
+  ;;
+esac
+
 case "$subcmd" in
 (plugin-add)
-  if (( CURRENT == 3 )); then
+  if (( CURRENT == 3 + IntermediateCount )); then
     _asdf__available_plugins
   else
     # Optional URL
     curcontext="${curcontext/=plugin-add:/=plugin-add-${words[3]}:}"
-    if (( CURRENT == 4 )); then
+    if (( CURRENT == 4 + IntermediateCount )); then
       _arguments "*:${words[3]} package url:_urls"
     fi
   fi
   ;;
 (plugin-remove|current|list|list-all)
-  (( CURRENT == 3 )) && _asdf__installed_plugins
+  (( CURRENT == 3 + IntermediateCount )) && _asdf__installed_plugins
   ;;
 (plugin-update)
-  (( CURRENT == 3 )) && _alternative \
+  (( CURRENT == 3 + IntermediateCount )) && _alternative \
     'all:all:(--all)' \
     'asdf-available-plugins:Installed ASDF Plugins:_asdf__installed_plugins'
   ;;
 (install)
-  if (( CURRENT == 3 )); then
+  if (( CURRENT == 3 + IntermediateCount )); then
     _asdf__installed_plugins
-  elif (( CURRENT == 4 )); then
-    _wanted "remote-versions-${words[3]}" \
-      expl "Available versions of ${words[3]}" \
-      compadd -- $(asdf list-all "${words[3]}")
+  elif (( CURRENT == 4 + IntermediateCount )); then
+    local pkg="${words[3+IntermediateCount]}"
+    local ver_prefix="${words[4+IntermediateCount]}"
+    if [[ $ver_prefix == latest:* ]]; then
+      _wanted "latest-versions-$pkg" \
+        expl "Latest version" \
+        compadd -- latest:${^$(asdf list-all "$pkg")}
+    else
+      _wanted "latest-tag-$pkg" \
+        expl "Latest version" \
+        compadd -- 'latest' 'latest:'
+      _wanted "remote-versions-$pkg" \
+        expl "Available versions of $pkg" \
+        compadd -- $(asdf list-all "$pkg")
+    fi
+  fi
+  ;;
+(latest)
+  if (( CURRENT == 3 + IntermediateCount )); then
+    _asdf__installed_plugins
+  elif (( CURRENT == 4 + IntermediateCount )); then
+    local pkg="${words[3+IntermediateCount]}"
+    local query=${words[4+IntermediateCount]}
+    [[ -n $query ]] || query='[0-9]'
+    _wanted "latest-pattern-$pkg" \
+      expl "Pattern to look for in matching versions of $pkg" \
+      compadd -- $(asdf list-all "$pkg" "$query")
   fi
   ;;
 (uninstall|shell|local|global|reshim)