Pre-load pdx.lua and enable live-coding support by default.

Following up on rev. 7447be5, pdx.lua is now pre-loaded in pd.lua, and
all objects have live-coding enabled automatically, by calling
pdx.reload() immediately before intiialize(). Thus all that's needed is
a `[; pdluax reload(` message in your patch, or you can use the
pd-remote.pd abstraction, as described in the tutorial.

To make it possible to load pdx.lua from pd.lua (and possibly other
extension modules in the future), the pdlua external directory is now
always on Lua's `package.path`. Hence it was possible to revert
pd._setrequirepath() to take only one argument.

Note that if you don't want this, you can still disable pdx.lua globally
by commenting out the following line near the end of pd.lua:

    pdx = require 'pdx'

Or you can call pdx.unreload() in the initialize() method of your
object. But this shouldn't be necessary. pdx.lua incurs minimal
overhead, and even with pdx.lua pre-loaded, you can still use any of the
other live-coding approaches described in the tutorial if you prefer.

pd.lua

@@ -29,15 +29,15 @@ pd._loadpath = ""
 pd._currentpath = ""
 
 -- add a path to Lua's "require" search paths
-pd._setrequirepath = function(path, pdlua_path)
+pd._setrequirepath = function(path)
   pd._packagepath = package.path
   pd._packagecpath = package.cpath
   if (pd._iswindows) then
-    package.path = path .. "\\?;" .. path .. "\\?.lua;" .. pdlua_path .. "\\?;" .. pdlua_path .. "\\?.lua;" .. package.path
-    package.cpath = path .. "\\?.dll;" .. pdlua_path .. "\\?.dll;" .. package.cpath
+    package.path = path .. "\\?;" .. path .. "\\?.lua;" .. package.path
+    package.cpath = path .. "\\?.dll;" .. package.cpath
   else
-    package.path = path .. "/?;" .. path .. "/?.lua;" .. pdlua_path .. "/?;" .. pdlua_path .. "/?.lua;" .. package.path
-    package.cpath = path .. "/?.so;" .. pdlua_path .. "/?.so;" .. package.cpath
+    package.path = path .. "/?;" .. path .. "/?.lua;" .. package.path
+    package.cpath = path .. "/?.so;" .. package.cpath
   end
 end
 
@@ -344,6 +344,9 @@ function pd.Class:construct(sel, atoms)
   self.inlets = 0
   self.outlets = 0
   self._canvaspath = pd._canvaspath(self._object) .. "/"
+  if pdx then
+    pdx.reload(self)
+  end
   if self:initialize(sel, atoms) then
     pd._createinlets(self._object, self.inlets)
     pd._createoutlets(self._object, self.outlets)
@@ -353,6 +356,9 @@ function pd.Class:construct(sel, atoms)
     self:postinitialize()
     return self
   else
+    if pdx then
+      pdx.unreload(self)
+    end
     return nil
   end
 end
@@ -517,4 +523,9 @@ end
 DATA = 0
 SIGNAL = 1
 Colors = {background = 0, foreground = 1, outline = 2}
+
+-- pre-load pdx.lua (live coding support); if you don't want this, just
+-- comment out the line below
+pdx = require 'pdx'
+
 -- fin pd.lua

pdlua.c

@@ -175,7 +175,7 @@ void initialise_lua_state()
 // In plugdata we're linked statically and thus c_externdir is empty.
 // So we pass a data directory to the setup function instead and store it here.
 // ag: Renamed to pdlua_datadir since we also need this in vanilla when
-// setting up the Lua search path when loading a pd_lua file.
+// setting up Lua's package.path.
 char pdlua_datadir[MAXPDSTRING];
 #if PLUGDATA
     // Hook to inform plugdata which class names are lua objects
@@ -2037,6 +2037,29 @@ static int pdlua_error(lua_State *L)
     return 0;
 }
 
+static void pdlua_packagepath(lua_State *L, const char *path)
+{
+    PDLUA_DEBUG("pdlua_packagepath: stack top %d", lua_gettop(L));
+    lua_getglobal(L, "package");
+    lua_pushstring(L, "path");
+    lua_gettable(L, -2);
+    const char *packagepath = lua_tostring(L, -1);
+    char *buf = malloc(2*strlen(path)+20+strlen(packagepath));
+    if (!buf) return;
+#ifdef _WIN32
+    sprintf(buf, "%s\\?;%s\\?.lua;%s", path, path, packagepath);
+#else
+    sprintf(buf, "%s/?;%s/?.lua;%s", path, path, packagepath);
+#endif
+    lua_pop(L, 1);
+    lua_pushstring(L, "path");
+    lua_pushstring(L, buf);
+    lua_settable(L, -3);
+    free(buf);
+    lua_pop(L, 1);
+    PDLUA_DEBUG("pdlua_packagepath: end. stack top %d", lua_gettop(L));
+}
+
 static void pdlua_setrequirepath
 ( /* FIXME: documentation (is this of any use at all?) */
     lua_State   *L,
@@ -2048,8 +2071,7 @@ static void pdlua_setrequirepath
     lua_pushstring(L, "_setrequirepath");
     lua_gettable(L, -2);
     lua_pushstring(L, path);
-    lua_pushstring(L, pdlua_datadir);
-    if (lua_pcall(L, 2, 0, 0) != 0)
+    if (lua_pcall(L, 1, 0, 0) != 0)
     {
         pd_error(NULL, "lua: internal error in `pd._setrequirepath': %s", lua_tostring(L, -1));
         lua_pop(L, 1);
@@ -2579,6 +2601,12 @@ void pdlua_setup(void)
     if (fd >= 0)
     { /* pd.lua was opened */
         reader.fd = fd;
+        // We need to set up Lua's package.path here so that pdx.lua can be
+        // found (and possibly other pre-loaded extension modules in the
+        // future). Note that we can't just use pdlua_setrequirepath() here
+        // because it calls pd._setrequirepath in pd.lua which isn't loaded
+        // yet at this point.
+        pdlua_packagepath(__L(), pdlua_datadir);
 #if LUA_VERSION_NUM	< 502
         result = lua_load(__L(), pdlua_reader, &reader, "pd.lua");
 #else // 5.2 style

pdlua/tutorial/examples/luatab.pd_lua

@@ -1,15 +1,10 @@
 local luatab = pd.Class:new():register("luatab")
 
--- our own pdlua extension, needed for the reload functionality
-local pdx = require 'pdx'
-
 function luatab:initialize(sel, atoms)
    -- single inlet for the frequency, bang goes to the single outlet when we
    -- finished generating a new waveform
    self.inlets = 1
    self.outlets = 1
-   -- enable the reload callback
-   pdx.reload(self)
    -- the name of the array/table should be in the 1st creation argument
    if type(atoms[1]) == "string" then
       self.tabname = atoms[1]

pdlua/tutorial/examples/pdx.lua

@@ -3,10 +3,8 @@
 pdx.lua: useful extensions to pd.lua
 Copyright (C) 2020 Albert Gräf <[email protected]>
 
-To use this in your pd-lua scripts: local pdx = require 'pdx'
-
 Currently there's only the pdx.reload() function, which implements a kind of
-remote reload functionality based on dofile and receivers, as explained in the
+live coding functionality based on dofile and receivers, as explained in the
 pd-lua tutorial. More may be added in the future.
 
 This program is free software; you can redistribute it and/or
@@ -30,6 +28,13 @@ local pdx = {}
 Reload functionality. Call pdx.reload() on your object to enable, and
 pdx.unreload() to disable this functionality again.
 
+NOTE: As of pd-lua 0.12.8, this module is now pre-loaded, and pdx.reload()
+gets called automatically before running the initialize method of any object,
+so calling pdx.reload() explicitly is no longer needed. (Old code importing
+the module and doing the call will continue to work, though.) Instead, you
+will now have to call pdx.unreload() in your initialize method if you want to
+*disable* this feature for some reason.
+
 pdx.reload installs a "pdluax" receiver which reloads the object's script file
 when it receives the "reload" message without any arguments, or a "reload
 class" message with a matching class name.