simple function tracing

init.lua

@@ -0,0 +1,73 @@
+local MODNAME = core.get_current_modname()
+local MODPATH = core.get_modpath(MODNAME)
+
+local mod = {
+    MODNAME = MODNAME,
+    MODPATH = MODPATH,
+}
+_G[MODNAME] = mod
+
+local pack = table.pack or function(...) return {n = select("#", ...), ...} end
+local unpack = unpack or table.unpack
+
+local fmt = string.format
+
+mod.traced_funcs = {}
+
+local function log(dir, label, args, trace)
+    local fmt_args = {}
+    print(dump(args))
+    if args.n then
+        for i=1,args.n do
+            fmt_args[i] = fmt("%s", args[i])
+        end
+    end
+    
+    core.log("action", fmt("%s%s(%s) %s", dir, label, table.concat(fmt_args, ','), trace))
+end
+
+local function trace(t, key)
+    local func = t[key]
+    if type(func) ~= "function" then
+        return nil
+    end
+    local wrapper = function(...)
+        local args = pack(...)
+        log(">", key, args, debug.traceback("==============",2))
+        local ret = pack(func(...))
+        log("<", key, ret, "")
+        return unpack(ret)
+    end
+    mod.traced_funcs[wrapper] = {
+        t = t,
+        key = key,
+        func = func,
+    }
+    t[key] = wrapper
+    return wrapper
+end
+
+local function untrace(func)
+    local orig = mod.traced_funcs[func]
+    orig.t[orig.key] = orig.func
+    return orig.func
+end
+
+mod.trace = function(first, second)
+    if not second then
+        if type(first) ~= "string" then
+            return nil
+        end
+        core.log("action", fmt("* Tracing global %s()", first))
+        return trace(_G, first)
+    else
+        if type(first) ~= "table" or type(second) ~= "string" then
+            return nil
+        end
+        return trace(first, second)
+    end
+end
+
+mod.untrace = function(func)
+    return untrace(func)
+end