Misc changes.

limmutable.c

@@ -48,59 +48,6 @@ typedef struct {
     size_t len;
 } immutable_info_t;
 
-static int Lhash(lua_State *L)
-{
-    lua_Integer hash = 0x9a937c4d; // Seed
-    lua_Integer n = luaL_checkinteger(L, 1);
-    for (lua_Integer i=2; i <= lua_gettop(L); i++) {
-        lua_Integer item_hash;
-        int type = i > n ? LUA_TNIL : lua_type(L, i);
-        switch (type) {
-            case LUA_TNIL: case LUA_TNONE:
-                // Arbitrarily chosen value
-                item_hash = 0x97167da9;
-                break;
-            case LUA_TNUMBER:
-                {
-                    // Cast float bits to integer
-                    lua_Number num = lua_tonumber(L, i);
-                    item_hash = *((lua_Integer*)&num);
-                    if (item_hash == 0) {
-                        item_hash = 0x2887c992;
-                    }
-                    break;
-                }
-            case LUA_TBOOLEAN:
-                // Arbitrarily chosen values
-                item_hash = lua_toboolean(L, i)? 0x82684f71 : 0x88d66f2a;
-                break;
-            case LUA_TTABLE:
-            case LUA_TFUNCTION:
-            case LUA_TUSERDATA:
-            case LUA_TTHREAD:
-            case LUA_TLIGHTUSERDATA:
-                item_hash = (1000003 * type) ^ (lua_Integer)lua_topointer(L, i);
-                break;
-            case LUA_TSTRING:
-                {
-                    // Algorithm taken from Lua 5.3's implementation
-                    size_t len;
-                    const char *str = lua_tolstring(L, i, &len);
-                    item_hash = len ^ 0xd2e9e9ac; // Arbitrary seed
-                    size_t step = (len >> LUAI_HASHLIMIT) + 1;
-                    for (; len >= step; len -= step)
-                        item_hash ^= ((item_hash<<5) + (item_hash>>2) + (unsigned char)(str[len - 1]));
-                    break;
-                }
-            default:
-                item_hash = 0;
-        }
-        hash = (1000003 * hash) ^ item_hash;
-    }
-    lua_pushinteger(L, hash);
-    return 1;
-}
-
 static int Lcreate_instance(lua_State *L)
 {
     size_t n_args = lua_gettop(L)-1;
@@ -166,9 +113,7 @@ static int Lcreate_instance(lua_State *L)
     // Find bucket
     lua_rawgeti(L, -1, hash);
     // Stack: [buckets, bucket]
-    int created_bucket = 0;
     if (lua_isnil(L, -1)) {
-        created_bucket = 1;
         // Make a new bucket
         // Stack: [buckets, nil]
         lua_pop(L, 1);
@@ -184,36 +129,33 @@ static int Lcreate_instance(lua_State *L)
         // Stack: [buckets, bucket, bucket]
         lua_rawseti(L, -3, hash);
         // Stack: [buckets, bucket]
-    }
+    } else {
-    // Stack: [buckets, bucket]
+        // Stack: [buckets, bucket]
-    if (! created_bucket) {
         // scan bucket
         lua_pushnil(L);
         while (lua_next(L, -2) != 0) { // for hash_collider_inst, hash_collider in pairs(bucket) do
             // Stack: [buckets, bucket, hash_collider_inst, hash_collider]
-            int bucket_item_matches = 1;
             // Shallow equality check:
             lua_pushnil(L);
             while (lua_next(L, -2) != 0) { // for i, collider_value in pairs(hash_collider) do
                 // Stack: [buckets, bucket, hash_collider_inst, hash_collider, i, value]
                 if (!lua_rawequal(L, -1, 1+lua_tonumber(L, -2))) { // If the i'th entry doesn't match the i'th arg
-                    bucket_item_matches = 0;
                     // Stack: [buckets, bucket, hash_collider_inst, hash_collider, i, value]
                     lua_pop(L, 3);
                     // Stack: [buckets, bucket, hash_collider_inst]
-                    break; // go to next item in the bucket
+                    goto next_bucket_item;
                 } else {
                     // Stack: [buckets, bucket, hash_collider_inst, hash_collider, i, value]
                     lua_pop(L, 1);
                     // Stack: [buckets, bucket, hash_collider_inst, hash_collider, i]
                 }
             }
-            if (bucket_item_matches) {
+            // bucket item matches
-                // Stack: [buckets, bucket, hash_collider_inst, hash_collider]
+            // Stack: [buckets, bucket, hash_collider_inst, hash_collider]
-                lua_pop(L, 1);
+            lua_pop(L, 1);
-                // Found matching pre-existing instance
+            return 1;
-                return 1;
+
-            }
+            next_bucket_item: ;
         }
     }
 
@@ -258,7 +200,7 @@ static int Lcreate_instance(lua_State *L)
     // Stack [buckets, bucket, inst_userdata, inst_userdata, inst_table]
     lua_settable(L, -4); // buckets[inst_userdata] = inst_table
     // Stack [buckets, bucket, inst_userdata]
-    lua_gc(L, LUA_GCSTEP, 1);
+    lua_gc(L, LUA_GCSTEP, 3);
     return 1;
 }
 
@@ -344,6 +286,9 @@ static int Lindex(lua_State *L)
     lua_getfield(L, -1, "__indices");
     // Stack: [mt, indices]
     if (lua_isnil(L, -1)) {
+        if (! lua_isinteger(L, 2)) {
+            goto class_fallback;
+        }
         lua_pop(L, 1);
         // Stack: [mt]
         lua_getfield(L, -1, "__instances");
@@ -359,6 +304,9 @@ static int Lindex(lua_State *L)
         // Stack: [mt, buckets, bucket, inst_table]
         int i = luaL_checkinteger(L, 2);
         lua_rawgeti(L, -1, i);
+        if (lua_isnil(L, -1)) {
+            goto class_fallback;
+        }
         return 1;
     }
 
@@ -375,32 +323,30 @@ static int Lindex(lua_State *L)
             lua_pushvalue(L, 2);
         }
     }
-    if (! lua_isnil(L, -1)) { // Found the field name
+    if (lua_isnil(L, -1)) { // Didn't find the field name
-        // Stack: [mt, indices, i]
+        goto class_fallback;
-        lua_getfield(L, -3, "__instances");
-        // Stack: [mt, indices, i, buckets]
-        lua_rawgeti(L, -1, info->hash);
-        // Stack: [mt, indices, i, buckets, bucket]
-        if (lua_isnil(L, -1)) {
-            luaL_error(L, "Failed to find hash bucket for hash: %p", (void*)info->hash);
-        }
-        lua_pushvalue(L, 1);
-        // Stack: [mt, indices, i, buckets, bucket, inst_udata]
-        lua_rawget(L, -2);
-        // Stack: [mt, indices, i, buckets, bucket, inst_table]
-        int i = luaL_checkinteger(L, -4);
-        lua_rawgeti(L, -1, i);
-        return 1;
-    } else {
-        // Fall back to class:
-        // Stack: [mt, indices, nil]
-        lua_pop(L, 2);
-        // Stack: [mt]
-        lua_pushvalue(L, 2);
-        // Stack: [mt, key]
-        lua_gettable(L, -2);
-        return 1;
     }
+    // Stack: [mt, indices, i]
+    lua_getfield(L, -3, "__instances");
+    // Stack: [mt, indices, i, buckets]
+    lua_rawgeti(L, -1, info->hash);
+    // Stack: [mt, indices, i, buckets, bucket]
+    if (lua_isnil(L, -1)) {
+        luaL_error(L, "Failed to find hash bucket for hash: %p", (void*)info->hash);
+    }
+    lua_pushvalue(L, 1);
+    // Stack: [mt, indices, i, buckets, bucket, inst_udata]
+    lua_rawget(L, -2);
+    // Stack: [mt, indices, i, buckets, bucket, inst_table]
+    int i = luaL_checkinteger(L, -4);
+    lua_rawgeti(L, -1, i);
+    return 1;
+
+    // Fall back to class:
+  class_fallback:
+    lua_pushvalue(L, 2);
+    lua_gettable(L, 3);
+    return 1;
 }
 
 static int Ltostring(lua_State *L)
@@ -446,15 +392,12 @@ static int Ltostring(lua_State *L)
         lua_pop(L, 1);
         // Stack: [mt, buckets, bucket, inst_table, tostring]
         immutable_info_t *info = (immutable_info_t*)lua_touserdata(L, 1);
-        int n = info->len;
+        int n = info->len, i = 1;
-        int needs_comma = 0;
+        goto first_list_item;
-        for (int i = 1; i <= n; i++) {
+        while (++i <= n) {
             // Stack: [mt, buckets, bucket, inst_table, tostring, ???]
-            if (needs_comma) {
+            luaL_addstring(&b, ", ");
-                luaL_addstring(&b, ", ");
+          first_list_item:
-            } else {
-                needs_comma = 1;
-            }
             lua_pushvalue(L, tostring_index);
             // Stack: [mt, buckets, bucket, inst_table, tostring, ???, tostring]
             lua_rawgeti(L, inst_table_index, i);
@@ -465,16 +408,13 @@ static int Ltostring(lua_State *L)
             // Stack: [mt, buckets, bucket, inst_table, tostring, ???]
         }
     } else {
-        int num_fields = lua_objlen(L, -1);
         int fields_index = lua_gettop(L);
-        int needs_comma = 0;
+        int i = 1, num_fields = lua_objlen(L, -1);
-        for (int i = 1; i <= num_fields; i++) {
+        goto first_table_item;
+        while (++i <= num_fields) {
             // Stack: [mt, buckets, bucket, inst_table, tostring, fields, ???]
-            if (needs_comma) {
+            luaL_addstring(&b, ", ");
-                luaL_addstring(&b, ", ");
+          first_table_item:
-            } else {
-                needs_comma = 1;
-            }
             lua_pushvalue(L, tostring_index);
             // Stack: [mt, buckets, bucket, inst_table, tostring, fields, ???, tostring]
             lua_rawgeti(L, fields_index, i);
@@ -618,6 +558,25 @@ static int Lpairs(lua_State *L)
     return 3;
 }
 
+static int Ltable(lua_State *L)
+{
+    lua_getmetatable(L, 1);
+    // Stack: [mt]
+    lua_getfield(L, -1, "__instances");
+    // Stack: [mt, buckets]
+    immutable_info_t *info = (immutable_info_t *)lua_touserdata(L, 1);
+    lua_rawgeti(L, -1, info->hash);
+    // Stack: [mt, buckets, bucket]
+    if (lua_isnil(L, -1)) {
+        luaL_error(L, "Failed to find hash bucket for hash: %p", (void*)info->hash);
+    }
+    lua_pushvalue(L, 1);
+    // Stack: [mt, buckets, bucket, inst_udata]
+    lua_rawget(L, -2);
+    // Stack: [mt, buckets, bucket, inst_table]
+    return 1;
+}
+
 static const luaL_Reg Rinstance_metamethods[] =
 {
     { "__len", Llen},
@@ -627,6 +586,7 @@ static const luaL_Reg Rinstance_metamethods[] =
     { "__pairs", Lpairs},
     { "from_table", Lfrom_table},
     { "is_instance", Lis_instance},
+    { "table", Ltable},
     { NULL, NULL}
 };
 
@@ -753,7 +713,5 @@ LUALIB_API int luaopen_immutable(lua_State *L)
     lua_settable(L, LUA_REGISTRYINDEX);
 
     lua_pushcfunction(L, Lmake_class);
-    lua_pushcfunction(L, Lhash);
-    lua_setglobal(L, "extract_hash");
     return 1;
 }

tests.lua

@@ -252,6 +252,17 @@ test("Testing giant immutable table", function()
     pcall(function() T:from_table(values) end)
 end)
 
+test("Testing tuple iteration", function()
+    local T = immutable(nil)
+    local t = T(1,4,9,16)
+    local checks = {1,4,9,16}
+    for i,v in ipairs(t) do
+        assert(checks[i] == v)
+        checks[i] = nil
+    end
+    assert(next(checks) == nil)
+end)
+
 if num_errors == 0 then
     print(green.."All tests passed!"..reset)
 else