Parse options so they can be combined (e.g. `-kv`) and occur anywhere on the command line

bin/ruby-build

@@ -5,6 +5,39 @@ RUBY_BUILD_VERSION="20120524"
 set -E
 exec 3<&2 # preserve original stderr at fd 3
 
+
+lib() {
+  parse_options() {
+    OPTIONS=()
+    ARGUMENTS=()
+    local arg option index
+
+    for arg in "$@"; do
+      if [ "${arg:0:1}" = "-" ]; then
+        if [ "${arg:1:1}" = "-" ]; then
+          OPTIONS[${#OPTIONS[*]}]="${arg:2}"
+        else
+          index=1
+          while option="${arg:$index:1}"; do
+            [ -n "$option" ] || break
+            OPTIONS[${#OPTIONS[*]}]="$option"
+            index=$(($index+1))
+          done
+        fi
+      else
+        ARGUMENTS[${#ARGUMENTS[*]}]="$arg"
+      fi
+    done
+  }
+
+  if [ "$1" == "--$FUNCNAME" ]; then
+    declare -f "$FUNCNAME"
+    exit
+  fi
+}
+lib "$1"
+
+
 resolve_link() {
   $(type -p greadlink readlink | head -1) "$1"
 }
@@ -332,7 +365,7 @@ version() {
 
 usage() {
   { version
-    echo "usage: ruby-build [-v|--verbose] definition prefix"
+    echo "usage: ruby-build [-k|--keep] [-v|--verbose] definition prefix"
     echo "       ruby-build --definitions"
   } >&2
 
@@ -351,34 +384,41 @@ list_definitions() {
 
 
 unset VERBOSE
+unset KEEP_BUILD_PATH
 RUBY_BUILD_ROOT="$(abs_dirname "$0")/.."
 
-case "$1" in
-"-h" | "--help" )
-  usage without_exiting
-  { echo
-    echo "  -v/--verbose     Verbose mode: print compilation status to stdout"
-    echo "  --definitions    List all built-in definitions"
-    echo
-  } >&2
-  exit 0
-  ;;
-"--definitions" )
-  list_definitions
-  exit 0
-  ;;
-"--version" )
-  version
-  exit 0
-  ;;
-"-v" | "--verbose" )
-  VERBOSE=true
-  shift
-  ;;
-esac
+parse_options "$@"
 
+for option in "${OPTIONS[@]}"; do
+  case "$option" in
+  "h" | "help" )
+    usage without_exiting
+    { echo
+      echo "  -k/--keep        Do not remove source tree after installation"
+      echo "  -v/--verbose     Verbose mode: print compilation status to stdout"
+      echo "  --definitions    List all built-in definitions"
+      echo
+    } >&2
+    exit 0
+    ;;
+  "definitions" )
+    list_definitions
+    exit 0
+    ;;
+  "k" | "keep" )
+    KEEP_BUILD_PATH=true
+    ;;
+  "v" | "verbose" )
+    VERBOSE=true
+    ;;
+  "version" )
+    version
+    exit 0
+    ;;
+  esac
+done
 
-DEFINITION_PATH="$1"
+DEFINITION_PATH="${ARGUMENTS[0]}"
 if [ -z "$DEFINITION_PATH" ]; then
   usage
 elif [ ! -e "$DEFINITION_PATH" ]; then
@@ -391,20 +431,11 @@ elif [ ! -e "$DEFINITION_PATH" ]; then
   fi
 fi
 
-PREFIX_PATH="$2"
+PREFIX_PATH="${ARGUMENTS[1]}"
 if [ -z "$PREFIX_PATH" ]; then
   usage
 fi
 
-OPTIONS="$3"
-for option in $OPTIONS; do
-  case "$option" in
-    "-k" | "--keep" )
-      KEEP_BUILD_PATH="y"
-      ;;
-  esac
-done
-
 if [ -z "$TMPDIR" ]; then
   TMP="/tmp"
 else