Merge pull request #89 from inkarkat/individual-help-enhancement

Individual help enhancement

todo.sh

@@ -54,7 +54,7 @@ shorthelp()
 		    del|rm ITEM# [TERM]
 		    depri|dp ITEM#[, ITEM#, ITEM#, ...]
 		    do ITEM#[, ITEM#, ITEM#, ...]
-		    help
+		    help [ACTION...]
 		    list|ls [TERM...]
 		    listall|lsa [TERM...]
 		    listaddons
@@ -154,6 +154,12 @@ help()
 
 
 	EndVerboseHelp
+        actionsHelp
+        addonHelp
+}
+
+actionsHelp()
+{
     cat <<-EndActionsHelp
 		  Built-in Actions:
 		    add "THING I NEED TO DO +project @context"
@@ -200,8 +206,9 @@ help()
 		    do ITEM#[, ITEM#, ITEM#, ...]
 		      Marks task(s) on line ITEM# as done in todo.txt.
 
-		    help
-		      Display this help message.
+		    help [ACTION...]
+		      Display help about usage, options, built-in and add-on actions,
+		      or just the usage help for the passed ACTION(s).
 
 		    list [TERM...]
 		    ls [TERM...]
@@ -280,9 +287,6 @@ help()
 		      List the one-line usage of all built-in and add-on actions.
 
 	EndActionsHelp
-
-        addonHelp
-    exit 1
 }
 
 addonHelp()
@@ -304,6 +308,25 @@ addonHelp()
     fi
 }
 
+actionUsage()
+{
+    for actionName
+    do
+        action="${TODO_ACTIONS_DIR}/${actionName}"
+        if [ -f "$action" -a -x "$action" ]; then
+            "$action" usage
+        else
+            builtinActionUsage=$(actionsHelp | sed -n -e "/^    ${actionName//\//\\/} /,/^\$/p" -e "/^    ${actionName//\//\\/}$/,/^\$/p")
+            if [ "$builtinActionUsage" ]; then
+                echo "$builtinActionUsage"
+                echo
+            else
+                die "TODO: No action \"${actionName}\" exists."
+            fi
+        fi
+    done
+}
+
 die()
 {
     echo "$*"
@@ -1088,13 +1111,19 @@ case $action in
     ;;
 
 "help" )
-    if [ -t 1 ] ; then # STDOUT is a TTY
-        if which "${PAGER:-less}" >/dev/null 2>&1; then
-            # we have a working PAGER (or less as a default)
-            help | "${PAGER:-less}" && exit 0
+    shift  ## Was help; new $1 is first help topic / action name
+    if [ $# -gt 0 ]; then
+        # Don't use PAGER here; we don't expect much usage output from one / few actions.
+        actionUsage "$@"
+    else
+        if [ -t 1 ] ; then # STDOUT is a TTY
+            if which "${PAGER:-less}" >/dev/null 2>&1; then
+                # we have a working PAGER (or less as a default)
+                help | "${PAGER:-less}" && exit 0
+            fi
         fi
+        help # just in case something failed above, we go ahead and just spew to STDOUT
     fi
-    help # just in case something failed above, we go ahead and just spew to STDOUT
     ;;
 
 "shorthelp" )