update hot-reload README with a more comprehensive explanation of how to integrate it with other patches.

patches/hot-reload/README.md

@@ -19,7 +19,8 @@ Note that you're responsible yourself for reloading ressources like fonts, which
 A lot of components of dwl will also only get run on a trigger (the tiling for example).
 So not every change will be immediate.
 Furthermore, any patch adding more global state to dwl cannot currently be reloaded properly since
-we keep state in the cold part.
+we keep state in the cold part. These patches will still work and their functionality will (hopefully) be
+reloadable but you will need to restart the compositor once.
 
 #### Notes
 ##### reduce compile errors
@@ -30,9 +31,71 @@ So you may want to disable this compile option in order to get readable compiler
 This does depend on you having a notification daemon like `dunst` or `mako` running as well as
 having `notify-send` installed in order for the compositor to inform you of the reload.
 
+
 #### How?
 Most of all dwl functionality is moved into a shared object file `dwl.so`, which can be reloaded at runtime.
 
+#### How do I make this work with other patches?
+Most patches should already put everything in more or less the correct place but if they don't, then here is
+where you learn how to fix it.
+
+The concept itself is quite simple. We compile dwl.c twice once normally and once with the `HOT` macro defined.
+The first run will yield the executable and the second will yield a shared object file to be reloaded at runtime.
+From the cold part there are some newly available macros:
+> symbol names are written as-is, never as string literals
+* `TSYM(T, s)` dynamically loads the symbol `s` with type `T` from the shared object file use this if you need to call functions in the cold part (i.e. the `setup` function).
+* `CSYM(T, v)` dynamically accesses the value of the symbol `v` of type `T` from the shared object. Use this to query values from config.h for example.
+* `LISTEN_GLOBAL(E, L)` is similar to the `LISTEN` macro. `E` is an event and `L` the name of a global
+listener. Current implementation is a bit messy and I may fix it if someone bothers me about it.
+* `UNLISTEN(L)` takes a listener and unregisteres it. This is important for reloading.
+
+When adding new code there are some considerations to be made. Since dwl decorates all symbols with `static` by default, we cannot access them as-is.
+C's macro system is a bit too powerful though and we use this to our advantage. We will repeatedly define and
+undefine a macro called `static` in order to replace the `static` keyword inside some sections.
+This allows us to do less refactoring and preserve a lot of the original patch compatability since we're only
+strategically adding lines.
+As a general guide:
+* global state should be global for the cold part and `extern` in the cold part meaning it should be inside a block like this:
+    ```C
+    #ifdef HOT
+        #define static extern
+    #else
+        #define static 
+    #endif
+    ... // your global variables go here
+    #undef static
+    ```
+* function declarations should be visible in the hot part but not included in the cold part meaning they should be enclosed like this:
+    ```C
+    #ifdef HOT
+    #define static
+    ... // your function declarations go here
+    #undef static
+    #endif
+    ```
+* static data like the event handler structs in the current `main` branch are a bit more difficult but we will let them reside inside the hot part.
+Thus, we enclose them the same way we do functions:
+    ```C
+    #ifdef HOT
+    #define static
+    ... // your struct wl_listener event handlers go here
+    #undef static
+    #endif
+    ```
+* function definitions should go in the hot part, so they need to be inside a big block like this:
+    ```C
+    #ifdef HOT
+    ... // function definitions here
+    #endif
+* enfore use of the `LISTEN_GLOBAL` and `UNLISTEN` macros (I know this sucks but what can I do, I need to get
+access to the callbacks somehow). So you want
+    * `wl_list_remove(listener.link)` to become `UNLISTEN(listener)` and
+    * `wl_signal_add(event, global_listener)` to become `LISTEN_GLOBAL(event, global)listener`.
+* Make sure that any patch you're using also uses static everywhere.
+Note that you do not have to create additional such feature blocks most of the time (there's a huge
+`#ifdef HOT`-delimited codeblock at the bottom of dwl.c where all the function definitions go for example).
+If you have any troubles, feel free to reach out.
+
 ### Download
 - [0.7](/dwl/dwl-patches/raw/branch/main/patches/hot-reload/hot-reload-0.7.patch)
 - [main 2025-05-30](/dwl/dwl-patches/raw/branch/main/patches/hot-reload/hot-reload.patch)