Revamp ffood() and add listing features

ffood now employs simpler algorithm to choose file to import and also
is able to list module contents.

ffood.sh.in

@@ -1,38 +1,68 @@
 #!/bin/bash
 
 FFOOD_DATA_DIR=${FFOOD_DATA_DIR:-$HOME/.ffood}
+FFOOD_DIR=${FFOOD_DIR:-__FFOOD_DIR__}
 FFOOD_ARTIFACTS_DIR=${FFOOD_ARTIFACTS_DIR:-artifacts}
 FFOOD_DEBUG=${FFOOD_DEBUG:-false}
+FFOOD_INCLUDE=${FFOOD_INCLUDE:-$FFOOD_DIR/include}
 FFOOD_VERBOSE=${FFOOD_VERBOSE:-false}
 FFOOD_VERSION=__VERSION__
 
-die() {
-    echo "$@" >&2
-    exit 1
-}
-
 ffood() {
-    local ffood_dir="${FFOOD_DIR:-__FFOOD_DIR__}"
     case $1 in
+        __debug)
+            $FFOOD_DEBUG || return 0
+            shift
+            echo "debug: $@" >&2
+            ;;
+        __die)
+            shift
+            echo "$@" >&2
+            exit 1
+            ;;
+        doc)
+            ffood __die "not implemented (sorry...)"
+            ;;
         import)
-            if test -f "$ffood_dir/include/$2.sh";
-            then
-                . "$ffood_dir/include/$2.sh";
-                return $?
-            elif test -n "$FFOOD_INCLUDE" -a -f "$FFOOD_INCLUDE/$2.sh";
-            then
-                . "$FFOOD_INCLUDE/$2.sh"
-                return $?
-            elif test -f "./$2.sh";
-            then
-                . "./$2.sh"
-                return $?
-            else
-                die "cannot find library: $2"
-            fi
+            ffood __debug "importing module $2"
+            local mfile=$(ffood _list_mfiles_like $2 | head -1)
+            test -n "$mfile" || ffood __die "cannot find module $2"
+            ffood __debug "found module file: $mfile"
+            . $mfile
+            return $?
+            ;;
+        _list_all_functions)
+            local mfile
+            ffood _list_all_mfiles | while read mfile;
+            do
+                ffood _list_functions_in_mfile "$mfile"
+            done
+            ;;
+        _list_all_modules)
+            local mp mfn;
+            ffood _list_all_mfiles | while read mp;
+            do
+                mfn="${mp##*/}"
+                echo "${mfn%%.sh}"
+            done
+            ;;
+        _list_all_mfiles)
+            {
+                echo $FFOOD_INCLUDE/*.sh | tr ' ' '\n'
+                test -n "$FFOOD_PATH" && echo $FFOOD_PATH/*.sh
+            } | tr ' ' '\n'
+            ;;
+        _list_mfiles_like)
+            test -f "$FFOOD_INCLUDE/$2.sh"                  && echo "$FFOOD_INCLUDE/$2.sh"
+            test -n "$FFOOD_PATH" -a -f "$FFOOD_PATH/$2.sh" && echo "$FFOOD_PATH/$2.sh"
+            ;;
+        _list_functions_in_mfile)
+            local mfile="$2"
+            grep -HE '^[[:alnum:]_]+\(\) \{' "$mfile" \
+              | sed -e 's/^.*\///; s/\.sh:/./; s/(.*//'
             ;;
         *)
-            die "unknown ffood command: $1"
+            ffood __die "unknown ffood command: $1"
             ;;
     esac
 }