[archive] Support unarchive of multiple files

so we can do `unarchive *.tar.gz` for example.

Update README and compdef accordingly.

modules/archive/README.md

@@ -9,7 +9,7 @@ Functions
 ---------
 
   * `archive` generates an archive based on file extension. Syntax is `archive myarchive.tar.gz /path/to/archive`
-  * `unarchive` unarchives a file based on the extension. Syntax is `unarchive myarchive.7z`
+  * `unarchive` unarchives files based on the extensions. Syntax is `unarchive myarchive.7z`
 
 Archive formats
 ---------------

modules/archive/functions/_unarchive

@@ -1,4 +1,4 @@
 #compdef unarchive
 
 _arguments \
-  ":archive:_files -g '(#i)*.(tar|gz|tgz|bz2|tbz|tbz2|xz|txz|tlz|lzma|Z|zip|rar|7z|001)(-.)'"
+  "*:archive:_files -g '(#i)*.(tar|gz|tgz|bz|bz2|tbz|tbz2|xz|txz|tlz|lzma|Z|zip|rar|7z|001)(-.)'"

modules/archive/functions/unarchive

@@ -3,16 +3,18 @@
 # Unarchives files
 #
 
-if (( # != 1 )); then
-  print "usage: ${0} <archive_name.ext>" >&2
+if (( # < 1 )); then
+  print "usage: ${0} <archive_name.ext>..." >&2
   return 1
 fi
 
-local archive_name="${1}"
+setopt LOCAL_OPTIONS ERR_RETURN
 
 # using unpigz/pbunzip2 provides little to decompression time; the benefit is mainly in compression time.
 # setting it as an alias in the init.zsh file should be sufficient here.
 
+while (( # > 0 )); do
+  local archive_name="${1}"
   case "${archive_name}" in
     (*.tar.gz|*.tgz) tar -xvzf "${archive_name}" ;;
     (*.tar.bz|*.tar.bz2|*.tbz|*.tbz2) tar -xvjf "${archive_name}" ;;
@@ -30,5 +32,10 @@ case "${archive_name}" in
     (*.rar) (( $+{commands[unrar]} )) && unrar x -ad "${archive_name}" \
       || rar x -ad "${archive_name}" ;;
     (*.7z|*.001) 7za x "${archive_name}" ;;
-  (*) print "${0}: unknown archive type: ${archive_name}" ;;
+    (*)
+      print "${0}: unknown archive type: ${archive_name}"
+      return 1
+      ;;
   esac
+  shift
+done