Lua Power Patches

Lua power patches are patches for the Lua interpreter that modify its behavior in some way. Here are some patches that I've written.

This patch allows you to retrieve the source (as in which dynamic module a function is defined in) of a C function with the debug library instead of always using '=[C]'.

c-func-source.patch

diff -Naur lua-5.1.4/src/Makefile my-lua-changes/src/Makefile
--- lua-5.1.4/src/Makefile	2008-01-19 13:37:58.000000000 -0600
+++ my-lua-changes/src/Makefile	2009-05-06 11:25:10.310376320 -0500
@@ -96,7 +96,7 @@
 	$(MAKE) all MYCFLAGS=
 
 linux:
-	$(MAKE) all MYCFLAGS=-DLUA_USE_LINUX MYLIBS="-Wl,-E -ldl -lreadline -lhistory -lncurses"
+	$(MAKE) all MYCFLAGS="-DLUA_USE_LINUX -DHAS_DLADDR=1" MYLIBS="-Wl,-E -ldl -lreadline -lhistory -lncurses"
 
 macosx:
 	$(MAKE) all MYCFLAGS=-DLUA_USE_LINUX MYLIBS="-lreadline"
diff -Naur lua-5.1.4/src/ldebug.c my-lua-changes/src/ldebug.c
--- lua-5.1.4/src/ldebug.c	2008-05-08 11:56:26.000000000 -0500
+++ my-lua-changes/src/ldebug.c	2009-05-06 11:30:46.990003983 -0500
@@ -28,6 +28,11 @@
 #include "ltm.h"
 #include "lvm.h"
 
+#if HAS_DLADDR
+#  define __USE_GNU
+#  define _GNU_SOURCE
+#  include <dlfcn.h>
+#endif
 
 
 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
@@ -149,7 +154,16 @@
 
 static void funcinfo (lua_Debug *ar, Closure *cl) {
   if (cl->c.isC) {
+#if HAS_DLADDR
+      Dl_info info;
+      if(dladdr(cl->c.f, &info)) {
+          ar->source = info.dli_fname;
+      } else {
+          ar->source = "=[C]";
+      }
+#else
     ar->source = "=[C]";
+#endif
     ar->linedefined = -1;
     ar->lastlinedefined = -1;
     ar->what = "C";
@@ -543,7 +557,20 @@
 
 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
   Instruction i;
-  if ((isLua(ci) && ci->tailcalls > 0) || !isLua(ci - 1))
+  if(!isLua(ci - 1)) {
+#if HAS_DLADDR
+      Dl_info info;
+      if(dladdr(ci_func(ci)->c.f, &info)) {
+          *name = info.dli_sname;
+          return "cfunction"; /* for now */
+      } else {
+          return NULL;
+      }
+#else
+      return NULL;
+#endif
+  }
+  if (isLua(ci) && ci->tailcalls > 0)
     return NULL;  /* calling function is not Lua (or is unknown) */
   ci--;  /* calling function */
   i = ci_func(ci)->l.p->code[currentpc(L, ci)];

This patch allows you to insert underscores arbitrarily into numbers, like you can in Perl. This allows you to type 1_000_000 for 1 million.

perl-numbers.patch

diff -Naur lua-5.1.4/src/llex.c my-lua-changes/src/llex.c
--- lua-5.1.4/src/llex.c	2007-12-27 07:02:25.000000000 -0600
+++ my-lua-changes/src/llex.c	2009-04-06 12:37:07.496444467 -0500
@@ -190,10 +190,14 @@
 
 /* LUA_NUMBER */
 static void read_numeral (LexState *ls, SemInfo *seminfo) {
-  lua_assert(isdigit(ls->current));
+  lua_assert(isdigit(ls->current) || ls->current == '_');
   do {
-    save_and_next(ls);
-  } while (isdigit(ls->current) || ls->current == '.');
+    if(ls->current == '_') {
+      next(ls);
+    } else {
+      save_and_next(ls);
+    }
+  } while (isdigit(ls->current) || ls->current == '.' || ls->current == '_');
   if (check_next(ls, "Ee"))  /* `E'? */
     check_next(ls, "+-");  /* optional exponent sign */
   while (isalnum(ls->current) || ls->current == '_')