1 files changed, 286 insertions, 109 deletions

diff --git a/src/fallback.c b/src/fallback.c
index 5718f5c1..5a0b5a5b 100644
--- a/src/fallback.c
+++ b/src/fallback.c
@@ -3,130 +3,37 @@
 ** TecCGraf - PUC-Rio
 */
  
-char *rcs_fallback="$Id: fallback.c,v 1.25 1996/04/25 14:10:00 roberto Exp $";
+char *rcs_fallback="$Id: fallback.c,v 2.9 1997/06/23 18:27:53 roberto Exp $";
 
 #include <stdio.h>
 #include <string.h>
  
-#include "mem.h"
+#include "auxlib.h"
+#include "luamem.h"
 #include "fallback.h"
 #include "opcode.h"
 #include "lua.h"
 #include "table.h"
+#include "tree.h"
+#include "hash.h"
 
 
-static void errorFB (void);
-static void indexFB (void);
-static void gettableFB (void);
-static void arithFB (void);
-static void concatFB (void);
-static void orderFB (void);
-static void GDFB (void);
-static void funcFB (void);
 
-
-/*
-** Warning: This list must be in the same order as the #define's
-*/
-struct FB  luaI_fallBacks[] = {
-{"error", {LUA_T_CFUNCTION, {errorFB}}, 1, 0},
-{"index", {LUA_T_CFUNCTION, {indexFB}}, 2, 1},
-{"gettable", {LUA_T_CFUNCTION, {gettableFB}}, 2, 1},
-{"arith", {LUA_T_CFUNCTION, {arithFB}}, 3, 1},
-{"order", {LUA_T_CFUNCTION, {orderFB}}, 3, 1},
-{"concat", {LUA_T_CFUNCTION, {concatFB}}, 2, 1},
-{"settable", {LUA_T_CFUNCTION, {gettableFB}}, 3, 0},
-{"gc", {LUA_T_CFUNCTION, {GDFB}}, 1, 0},
-{"function", {LUA_T_CFUNCTION, {funcFB}}, -1, -1},
-                                /* no fixed number of params or results */
-{"getglobal", {LUA_T_CFUNCTION, {indexFB}}, 1, 1}
-                                /* same default behavior of index FB */
-};
-
-#define N_FB  (sizeof(luaI_fallBacks)/sizeof(struct FB))
-
-void luaI_setfallback (void)
-{
-  int i;
-  char *name = lua_getstring(lua_getparam(1));
-  lua_Object func = lua_getparam(2);
-  if (name == NULL || !lua_isfunction(func))
-    lua_error("incorrect argument to function `setfallback'");
-  for (i=0; i<N_FB; i++)
-  {
-    if (strcmp(luaI_fallBacks[i].kind, name) == 0)
-    {
-      luaI_pushobject(&luaI_fallBacks[i].function);
-      luaI_fallBacks[i].function = *luaI_Address(func);
-      return;
-    }
-  }
-  /* name not found */
-  lua_error("incorrect argument to function `setfallback'");
-}
-
-
-static void errorFB (void)
-{
-  lua_Object o = lua_getparam(1);
-  if (lua_isstring(o))
-    fprintf (stderr, "lua: %s\n", lua_getstring(o));
-  else
-    fprintf(stderr, "lua: unknown error\n");
-}
- 
-
-static void indexFB (void)
-{
-  lua_pushnil();
-}
- 
-
-static void gettableFB (void)
-{
-  lua_error("indexed expression not a table");
-}
- 
-
-static void arithFB (void)
-{
-  lua_error("unexpected type at conversion to number");
-}
-
-static void concatFB (void)
-{
-  lua_error("unexpected type at conversion to string");
-}
-
-
-static void orderFB (void)
-{
-  lua_error("unexpected type at comparison");
-}
-
-static void GDFB (void) { }
-
-static void funcFB (void)
-{
-  lua_error("call expression not a function");
-}
-
-
-/*
+/* -------------------------------------------
 ** Reference routines
 */
 
 static struct ref {
-  Object o;
+  TObject o;
   enum {LOCK, HOLD, FREE, COLLECTED} status;
 } *refArray = NULL;
 static int refSize = 0;
 
-int luaI_ref (Object *object, int lock)
+int luaI_ref (TObject *object, int lock)
 {
   int i;
   int oldSize;
-  if (tag(object) == LUA_T_NIL)
+  if (ttype(object) == LUA_T_NIL)
     return -1;   /* special ref for nil */
   for (i=0; i<refSize; i++)
     if (refArray[i].status == FREE)
@@ -151,9 +58,9 @@ void lua_unref (int ref)
 }
 
 
-Object *luaI_getref (int ref)
+TObject *luaI_getref (int ref)
 {
-  static Object nul = {LUA_T_NIL, {0}};
+  static TObject nul = {LUA_T_NIL, {0}};
   if (ref == -1)
     return &nul;
   if (ref >= 0 && ref < refSize &&
@@ -164,7 +71,7 @@ Object *luaI_getref (int ref)
 }
 
 
-void luaI_travlock (int (*fn)(Object *))
+void luaI_travlock (int (*fn)(TObject *))
 {
   int i;
   for (i=0; i<refSize; i++)
@@ -181,11 +88,281 @@ void luaI_invalidaterefs (void)
       refArray[i].status = COLLECTED;
 }
 
-char *luaI_travfallbacks (int (*fn)(Object *))
+
+/* -------------------------------------------
+* Internal Methods 
+*/
+
+char *luaI_eventname[] = {  /* ORDER IM */
+  "gettable", "settable", "index", "getglobal", "setglobal", "add",
+  "sub", "mul", "div", "pow", "unm", "lt", "le", "gt", "ge",
+  "concat", "gc", "function",
+  NULL
+};
+
+
+
+static int luaI_checkevent (char *name, char *list[])
+{
+  int e = luaI_findstring(name, list);
+  if (e < 0)
+    luaL_verror("`%s' is not a valid event name", name);
+  return e;
+}
+
+
+struct IM *luaI_IMtable = NULL;
+
+static int IMtable_size = 0;
+static int last_tag = LUA_T_NIL;  /* ORDER LUA_T */
+
+
+/* events in LUA_T_LINE are all allowed, since this is used as a
+*  'placeholder' for "default" fallbacks
+*/
+static char validevents[NUM_TYPES][IM_N] = { /* ORDER LUA_T, ORDER IM */
+{1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1},  /* LUA_T_USERDATA */
+{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},  /* LUA_T_LINE */
+{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},  /* LUA_T_CMARK */
+{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},  /* LUA_T_MARK */
+{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0},  /* LUA_T_CFUNCTION */
+{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0},  /* LUA_T_FUNCTION */
+{0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},  /* LUA_T_ARRAY */
+{1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},  /* LUA_T_STRING */
+{1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1},  /* LUA_T_NUMBER */
+{1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}   /* LUA_T_NIL */
+};
+
+static int validevent (lua_Type t, int e)
+{ /* ORDER LUA_T */
+  return (t < LUA_T_NIL) ?  1 : validevents[-t][e];
+}
+
+
+static void init_entry (int tag)
 {
   int i;
-  for (i=0; i<N_FB; i++)
-    if (fn(&luaI_fallBacks[i].function))
-      return luaI_fallBacks[i].kind;
+  for (i=0; i<IM_N; i++)
+    ttype(luaI_getim(tag, i)) = LUA_T_NIL;
+}
+
+void luaI_initfallbacks (void)
+{
+  if (luaI_IMtable == NULL) {
+    int i;
+    IMtable_size = NUM_TYPES+10;
+    luaI_IMtable = newvector(IMtable_size, struct IM);
+    for (i=LUA_T_NIL; i<=LUA_T_USERDATA; i++)
+      init_entry(i);
+  }
+}
+
+int lua_newtag (void)
+{
+  --last_tag;
+  if ((-last_tag) >= IMtable_size) {
+    luaI_initfallbacks();
+    IMtable_size = growvector(&luaI_IMtable, IMtable_size,
+                              struct IM, memEM, MAX_INT);
+  }
+  init_entry(last_tag);
+  return last_tag;
+}
+
+
+static void checktag (int tag)
+{
+  if (!(last_tag <= tag && tag <= 0))
+    luaL_verror("%d is not a valid tag", tag);
+}
+
+void luaI_realtag (int tag)
+{
+  if (!(last_tag <= tag && tag < LUA_T_NIL))
+    luaL_verror("tag %d is not result of `newtag'", tag);
+}
+
+
+void luaI_settag (int tag, TObject *o)
+{
+  luaI_realtag(tag);
+  switch (ttype(o)) {
+    case LUA_T_ARRAY:
+      o->value.a->htag = tag;
+      break;
+    case LUA_T_USERDATA:
+      o->value.ts->tag = tag;
+      break;
+    default:
+      luaL_verror("cannot change the tag of a %s", luaI_typenames[-ttype(o)]);
+  }
+}
+
+
+int luaI_efectivetag (TObject *o)
+{
+  lua_Type t = ttype(o);
+  if (t == LUA_T_USERDATA) {
+    int tag = o->value.ts->tag;
+    return (tag >= 0) ? LUA_T_USERDATA : tag;
+  }
+  else if (t == LUA_T_ARRAY)
+    return o->value.a->htag;
+  else return t;
+}
+
+
+void luaI_gettagmethod (void)
+{
+  int t = (int)luaL_check_number(1);
+  int e = luaI_checkevent(luaL_check_string(2), luaI_eventname);
+  checktag(t);
+  if (validevent(t, e))
+    luaI_pushobject(luaI_getim(t,e));
+}
+
+
+void luaI_settagmethod (void)
+{
+  int t = (int)luaL_check_number(1);
+  int e = luaI_checkevent(luaL_check_string(2), luaI_eventname);
+  lua_Object func = lua_getparam(3);
+  checktag(t);
+  if (!validevent(t, e))
+    luaL_verror("cannot change internal method `%s' for tag %d",
+                luaI_eventname[e], t);
+  luaL_arg_check(lua_isnil(func) || lua_isfunction(func),
+                 3, "function expected");
+  luaI_pushobject(luaI_getim(t,e));
+  *luaI_getim(t, e) = *luaI_Address(func);
+}
+
+
+static void stderrorim (void)
+{
+  lua_Object s = lua_getparam(1);
+  if (lua_isstring(s))
+    fprintf(stderr, "lua: %s\n", lua_getstring(s));
+}
+
+static TObject errorim = {LUA_T_CFUNCTION, {stderrorim}};
+
+
+TObject *luaI_geterrorim (void)
+{
+  return &errorim;
+}
+
+void luaI_seterrormethod (void)
+{
+  lua_Object func = lua_getparam(1);
+  luaL_arg_check(lua_isnil(func) || lua_isfunction(func),
+                 1, "function expected");
+  luaI_pushobject(&errorim);
+  errorim = *luaI_Address(func);
+}
+
+char *luaI_travfallbacks (int (*fn)(TObject *))
+{
+  int e;
+  if (fn(&errorim))
+    return "error";
+  for (e=IM_GETTABLE; e<=IM_FUNCTION; e++) {  /* ORDER IM */
+    int t;
+    for (t=0; t>=last_tag; t--)
+      if (fn(luaI_getim(t,e)))
+        return luaI_eventname[e];
+  }
   return NULL;
 }
+
+
+/*
+* ===================================================================
+* compatibility with old fallback system
+*/
+#if	LUA_COMPAT2_5
+
+static void errorFB (void)
+{
+  lua_Object o = lua_getparam(1);
+  if (lua_isstring(o))
+    fprintf (stderr, "lua: %s\n", lua_getstring(o));
+  else
+    fprintf(stderr, "lua: unknown error\n");
+}
+ 
+
+static void nilFB (void) { }
+ 
+
+static void typeFB (void)
+{
+  lua_error("unexpected type");
+}
+
+
+static void fillvalids (IMS e, TObject *func)
+{
+  int t;
+  for (t=LUA_T_NIL; t<=LUA_T_USERDATA; t++)
+    if (validevent(t, e))
+      *luaI_getim(t, e) = *func;
+}
+
+
+void luaI_setfallback (void)
+{
+  static char *oldnames [] = {"error", "getglobal", "arith", "order", NULL};
+  TObject oldfunc;
+  lua_CFunction replace;
+  char *name = luaL_check_string(1);
+  lua_Object func = lua_getparam(2);
+  luaI_initfallbacks();
+  luaL_arg_check(lua_isfunction(func), 2, "function expected");
+  switch (luaI_findstring(name, oldnames)) {
+    case 0:  /* old error fallback */
+      oldfunc = errorim;
+      errorim = *luaI_Address(func);
+      replace = errorFB;
+      break;
+    case 1:  /* old getglobal fallback */
+      oldfunc = *luaI_getim(LUA_T_NIL, IM_GETGLOBAL);
+      *luaI_getim(LUA_T_NIL, IM_GETGLOBAL) = *luaI_Address(func);
+      replace = nilFB;
+      break;
+    case 2: {  /* old arith fallback */
+      int i;
+      oldfunc = *luaI_getim(LUA_T_NUMBER, IM_POW);
+      for (i=IM_ADD; i<=IM_UNM; i++)  /* ORDER IM */
+        fillvalids(i, luaI_Address(func));
+      replace = typeFB;
+      break;
+    }
+    case 3: {  /* old order fallback */
+      int i;
+      oldfunc = *luaI_getim(LUA_T_LINE, IM_LT);
+      for (i=IM_LT; i<=IM_GE; i++)  /* ORDER IM */
+        fillvalids(i, luaI_Address(func));
+      replace = typeFB;
+      break;
+    }
+    default: {
+      int e;
+      if ((e = luaI_findstring(name, luaI_eventname)) >= 0) {
+        oldfunc = *luaI_getim(LUA_T_LINE, e);
+        fillvalids(e, luaI_Address(func));
+        replace = (e == IM_GC || e == IM_INDEX) ? nilFB : typeFB;
+      }
+      else {
+        luaL_verror("`%s' is not a valid fallback name", name);
+        replace = NULL;  /* to avoid warnings */
+      }
+    }
+  }
+  if (oldfunc.ttype != LUA_T_NIL)
+    luaI_pushobject(&oldfunc);
+  else
+    lua_pushcfunction(replace);
+}
+#endif