Make default dependency officially optional

API.md

@@ -1,8 +1,12 @@
 # Easyvend API
-Use this API if you want to make an comntainer compatible with vending and
+Use this API if you want to make an container compatible with vending and
 depositing machines.
 
-The API only has one function:
+## How it works
+
+* Add `easyvend` as optional dependency
+* Check for existance of `easyvend` mod in code
+* Call `easyvend.register_chest` for all containers you want to be compatible
 
 ## `easyvend.register_chest = function(node_name, inv_list, meta_owner)`
 Registers a node (called “chest”) for use with Easyvend. After calling this function,
@@ -20,6 +24,14 @@ Easyvend makes the following assumptions about the chest:
 * `meta_owner`: Identifier of the metadata variable storing the owner name
 
 ### Example
+
+Register the node `example:superchest` as container:
+
 ```
-easyvend.register_chest("example:superchest", "main", "owner")
+if minetest.get_modpath("easyvend") then
+    easyvend.register_chest("example:superchest", "main", "owner")
+end
 ```
+
+The `if` check is a common trick to check for the existance of the `easyvend`
+and allows you to make the dependency optional.

README.md

@@ -4,6 +4,14 @@ Version: 0.4.3
 Adds vending and depositing machines which allow to buy and sell items from
 other players.
 
+## Requirements
+Runs natively in Minetest Game.
+
+May also run in other games if they have the `default` mod and locked chest
+(`default:chest_locked`).
+
+Locked chests from other mods are not supported, but mods can choose
+to add support for Easyvend on their own (see developer information below).
 
 ## How to use
 Help is also included as help entry for Item Documentation [`doc_items`].
@@ -24,8 +32,6 @@ But it can be changed via the setting `easyvend_currency`.
 
 
 
-
-
 ## Appendix
 ### Developer information
 If you want to a container node compatible with vending/depositing machines,

depends.txt

@@ -1,4 +1,4 @@
-default
+default?
 screwdriver?
 doc?
 doc_items?