allow prefix matching for actions

This offers some command line convenience, allowing the user only
specify an action prefix as long as it can be resolved without
ambiguitiy. For example, as of this commit, 'asp up' would then
translate to 'asp update', and 'asp d' would be an error (as 'difflog'
and 'disk-usage' are both candidates).

1 files changed, 108 insertions, 57 deletions

diff --git a/asp.in b/asp.in
index a0fdb2e..187416a 100644
--- a/asp.in
+++ b/asp.in
@@ -171,6 +171,113 @@ disk_usage() {
   log_info 'Using %s on disk.' "$usage"
 }
 
+action__checkout() {
+  map package_checkout "$@"
+}
+
+action__difflog() {
+  difflog "$1"
+}
+
+action__disk-usage() {
+  disk_usage
+}
+
+action__export() {
+  map package_export "$@"
+}
+
+action__gc() {
+  gc
+}
+
+action__help() {
+  usage
+}
+
+action__list-all() {
+  list_all
+}
+
+action__list-arches() {
+  map package_get_arches "$@"
+}
+
+action__list-local() {
+  list_local
+}
+
+action__list-repos() {
+  map package_get_repos "$@"
+}
+
+action__log() {
+  log "$1"
+}
+
+action__shortlog() {
+  shortlog "$1"
+}
+
+action__show() {
+  package_show_pkgbuild "$1"
+}
+
+action__untrack() {
+  map untrack "$@"
+}
+
+action__update() {
+  update_packages "$@"
+}
+
+dispatch_action() {
+  local a candidates=()
+  local actions=(
+    checkout
+    difflog
+    disk-usage
+    export
+    gc
+    help
+    list-all
+    list-arches
+    list-local
+    list-repos
+    log
+    shortlog
+    show
+    untrack
+    update
+  )
+
+  [[ $1 ]] || log_fatal 'no action specified (use -h for help)'
+
+  for a in "${actions[@]}"; do
+    if [[ $a = "$1" ]]; then
+      candidates=("$a")
+      break
+    fi
+
+    [[ $a = "$1"* ]] && candidates+=("$a")
+  done
+
+  case ${#candidates[*]} in
+    0)
+      log_fatal 'unknown action: %s' "$1"
+      ;;
+    1)
+      "action__${candidates[0]}" "${@:2}"
+      ;;
+    *)
+      {
+        printf "error: verb '%s' is ambiguous; possibilities:" "$1"
+        printf " '%s'" "${candidates[@]}"
+        echo
+      } >&2
+  esac
+}
+
 umask 0022
 startdir=$PWD
 cd "$ASPROOT" || log_fatal "ASPROOT ($ASPROOT) does not exist!"
@@ -202,61 +309,5 @@ while getopts ':a:fhV' flag; do
 done
 shift $(( OPTIND - 1 ))
 
-action=$1
-shift
-
-case $action in
-  update)
-    update_packages "$@"
-    ;;
-  list-repos)
-    map package_get_repos "$@"
-    ;;
-  list-arches)
-    map package_get_arches "$@"
-    ;;
-  list-all)
-    list_all
-    ;;
-  list-local)
-    list_local
-    ;;
-  export)
-    map package_export "$@"
-    ;;
-  shortlog)
-    shortlog "$1"
-    ;;
-  log)
-    log "$1"
-    ;;
-  show)
-    package_show_pkgbuild "$1"
-    ;;
-  difflog)
-    difflog "$1"
-    ;;
-  disk-usage)
-    disk_usage
-    ;;
-  gc)
-    gc
-    ;;
-  untrack)
-    map untrack "$@"
-    ;;
-  help)
-    usage
-    exit 0
-    ;;
-  checkout)
-    map package_checkout "$@"
-    ;;
-  '')
-    log_fatal 'no action specified (use -h for help)'
-    ;;
-  *)
-    log_fatal 'unknown action: %s' "$action"
-    ;;
-esac
+dispatch_action "$@"