adding brief code-style section to Developer_tips

docs/Developer_tips.md

@@ -19,3 +19,49 @@ C functions defined within `shared/` must also be bound by a file within `lisp/`
 more information on this will be provided in this document later.
 
 
+Code formatting
+---------------
+
+C code is automatically formatted using `clang-format`,
+if you have `clang-format` installed you can invoke the formatter via running:
+
+    # from the top level directory
+    $ cmake .
+    $ make format
+
+It is recommend that you format your code before making a pull request,
+although semi-regular formats are run to catch any code that wasn't
+pre-formatted.
+
+
+A quick outline of the C style:
+
+ - 2 space indent
+ - Never use tabs
+ - No column width limit
+
+
+A very short example showing some of the features of this style
+
+    int main(int argc, char **argv) {
+      int a = 14;
+      int *b = &a;
+
+      switch(a) {
+      case 14:
+        puts("a was 14")
+        break;
+
+      default:
+        puts("I have no idea what happened")
+        break;
+      }
+
+      if(*b > 5) {
+        puts("*b is bigger than 5")
+      }
+      else {
+        puts("*b is not bigger than 5")
+      }
+    }
+