feat(main): highlight apt-get subcommands

Add apt-get subcommand detection alongside apt handling, including cached
lookup from apt-get help output and fallback built-in subcommands.

Update tests to verify valid apt-get subcommands are highlighted as commands
and invalid ones as unknown tokens.feat(main): highlight apt-get subcommands

Add apt-get subcommand detection alongside apt handling, including cached
lookup from apt-get help output and fallback built-in subcommands.

Update tests to verify valid apt-get subcommands are highlighted as commands
and invalid ones as unknown tokens.

highlighters/main/main-highlighter.zsh

@@ -300,6 +300,37 @@ _zsh_highlight_main__is_apt_subcommand() {
   (( ${+_zsh_highlight_main__apt_subcommands[$1]} ))
 }
 
+# Check whether $1 is an apt-get subcommand.
+#
+# Return 0 if it is, 1 if it is not, and 2 if the subcommand list could not be
+# obtained.  The list is loaded once, on first use.
+_zsh_highlight_main__is_apt_get_subcommand() {
+  if (( ! _zsh_highlight_main__apt_get_subcommands_loaded )); then
+    local line
+    local -a words
+    local output
+
+    _zsh_highlight_main__apt_get_subcommands=(
+      help 1
+      indextargets 1
+      markauto 1
+      unmarkauto 1
+    )
+    output="$(LC_ALL=C command apt-get help 2>/dev/null)" || return 2
+
+    for line in ${(f)output}; do
+      if [[ $line == '  '*' - '* ]]; then
+        words=(${=line})
+        (( $#words )) && _zsh_highlight_main__apt_get_subcommands[$words[1]]=1
+      fi
+    done
+
+    _zsh_highlight_main__apt_get_subcommands_loaded=1
+  fi
+
+  (( ${+_zsh_highlight_main__apt_get_subcommands[$1]} ))
+}
+
 # Check whether the first argument is a redirection operator token.
 # Report result via the exit code.
 _zsh_highlight_main__is_redirection() {
@@ -1155,6 +1186,8 @@ _zsh_highlight_main_highlighter_highlight_list()
         esac
         if [[ $arg == apt && $res == (command|hashed) ]]; then
           next_word+=':apt-subcommand:'
+        elif [[ $arg == apt-get && $res == (command|hashed) ]]; then
+          next_word+=':apt-get-subcommand:'
         fi
       fi
       if [[ -n ${(M)ZSH_HIGHLIGHT_TOKENS_CONTROL_FLOW:#"$arg"} ]]; then
@@ -1224,6 +1257,15 @@ _zsh_highlight_main_highlighter_highlight_list()
                       _zsh_highlight_main_highlighter_highlight_argument 1 $(( 1 != in_redirection ))
                       continue
                     fi
+                  elif [[ $this_word == *':apt-get-subcommand:'* ]]; then
+                    if _zsh_highlight_main__is_apt_get_subcommand ${(Q)arg}; then
+                      style=command
+                    elif (( $? == 1 )); then
+                      style=unknown-token
+                    else
+                      _zsh_highlight_main_highlighter_highlight_argument 1 $(( 1 != in_redirection ))
+                      continue
+                    fi
                   else
                     _zsh_highlight_main_highlighter_highlight_argument 1 $(( 1 != in_redirection ))
                     continue
@@ -1909,4 +1951,6 @@ else
 fi
 typeset -gA _zsh_highlight_main__apt_subcommands
 typeset -gi _zsh_highlight_main__apt_subcommands_loaded=0
+typeset -gA _zsh_highlight_main__apt_get_subcommands
+typeset -gi _zsh_highlight_main__apt_get_subcommands_loaded=0
 typeset -ga ZSH_HIGHLIGHT_DIRS_BLACKLIST

highlighters/main/test-data/apt-other-commands.zsh

@@ -28,15 +28,27 @@
 # vim: ft=zsh sw=2 ts=2 et
 # -------------------------------------------------------------------------------------------------
 
-function apt-get() {}
 function apt-cache() {}
+hash apt-get=/bin/true
 
-BUFFER='apt-get isntall; apt-cache isntall'
+_zsh_highlight_main__apt_get_subcommands=(
+  install 1
+  dselect-upgrade 1
+)
+_zsh_highlight_main__apt_get_subcommands_loaded=1
+
+BUFFER='apt-get install; apt-get dselect-upgrade; apt-get isntall; apt-cache isntall'
 
 expected_region_highlight=(
-  '1 7 function' # apt-get
-  '9 15 default' # isntall
+  '1 7 command' # apt-get
+  '9 15 command' # install
   '16 16 commandseparator' # ;
-  '18 26 function' # apt-cache
-  '28 34 default' # isntall
+  '18 24 command' # apt-get
+  '26 40 command' # dselect-upgrade
+  '41 41 commandseparator' # ;
+  '43 49 command' # apt-get
+  '51 57 unknown-token' # isntall
+  '58 58 commandseparator' # ;
+  '60 68 function' # apt-cache
+  '70 76 default' # isntall
 )