template: allow aliasing escape funcs

template.lua

@@ -294,14 +294,22 @@ local make_stream = function(str)
     end
 end
 
+local esc_def = function(str)
+    return str
+end
+
 local escapes = {
-    ["default"] = function(str)
-        return str
-    end
+    ["default"] = esc_def
 }
 
 M.set_escape = function(style, func)
     local old = escapes[style]
+    if type(func) == "string" then
+        func = escapes[func]
+    end
+    if not func then
+        func = esc_def
+    end
     escapes[style] = func
     return old
 end