From 0ef2794f2a753e3a76545487a3ce925551ed64e2 Mon Sep 17 00:00:00 2001
From: Bruce Hill <bitbucket@bruce-hill.com>
Date: Fri, 9 Feb 2018 18:01:01 -0800
Subject: [PATCH] Fixed #, switched over to __instance_positions, deleted
 :new().

---
 limmutable.c | 113 +++++++++++++++++++++++++++++++++++++--------------
 test.lua     |   4 ++
 2 files changed, 86 insertions(+), 31 deletions(-)

diff --git a/limmutable.c b/limmutable.c
index ed3caa4..19d4e80 100644
--- a/limmutable.c
+++ b/limmutable.c
@@ -173,9 +173,11 @@ static int Lcreate_instance(lua_State *L)
 
 static int Llen(lua_State *L)
 {
-    lua_pushvalue(L, 1);
-    luaL_getmetatable(L, MYTYPE);
-    lua_getfield(L, -1, "fields");
+    lua_getmetatable(L, 1);
+    // Stack: [mt]
+    lua_getfield(L, -1, "__fields");
+    // Stack: [mt, fields]
+    lua_len(L, -1);
     return 1;
 }
 
@@ -183,31 +185,28 @@ static int Lindex(lua_State *L)
 {
     lua_getmetatable(L, 1);
     // Stack: [mt]
-    lua_getfield(L, -1, "__fields");
-    // Stack: [mt, fields]
-    
-    lua_pushnil(L);
-    while (lua_next(L, -2) != 0) {
-        // Stack: [mt, fields, i, field]
-        if (lua_rawequal(L, -1, 2)) {
-            lua_pop(L, 1);
-            // All the slowness is concentrated here
-            // Stack: [mt, fields, i]
-            lua_getfield(L, -3, "__instances");
-            // Stack: [mt, fields, i, buckets]
-            lua_rawgeti(L, -1, *((lua_Integer*)lua_touserdata(L, 1)));
-            // Stack: [mt, fields, i, buckets, bucket]
-            lua_pushvalue(L, 1);
-            // Stack: [mt, fields, i, buckets, bucket, inst_udata]
-            lua_rawget(L, -2);
-            // Stack: [mt, fields, i, buckets, bucket, inst_table]
-            lua_rawgeti(L, -1, lua_tonumber(L, -4));
-            // Stack: [mt, fields, i, buckets, bucket, inst_table, result]
-            return 1;
-        }
-        lua_pop(L, 1);
+    lua_getfield(L, -1, "__field_positions");
+    // Stack: [mt, field_positions]
+    lua_pushvalue(L, 2);
+    // Stack: [mt, field_positions, k]
+    lua_rawget(L, -2);
+    // Stack: [mt, field_positions, i]
+    if (! lua_isnil(L, -1)) {
+        // Stack: [mt, field_positions, i]
+        lua_getfield(L, -3, "__instances");
+        // Stack: [mt, field_positions, i, buckets]
+        lua_rawgeti(L, -1, *((lua_Integer*)lua_touserdata(L, 1)));
+        // Stack: [mt, field_positions, i, buckets, bucket]
+        lua_pushvalue(L, 1);
+        // Stack: [mt, field_positions, i, buckets, bucket, inst_udata]
+        lua_rawget(L, -2);
+        // Stack: [mt, field_positions, i, buckets, bucket, inst_table]
+        lua_rawgeti(L, -1, lua_tointeger(L, -4));
+        return 1;
     }
-    lua_pop(L, 1);
+    // Fall back to class:
+    // Stack: [mt, field_positions, i]
+    lua_pop(L, 2);
     // Stack: [mt]
     lua_pushvalue(L, 2);
     // Stack: [mt, key]
@@ -292,9 +291,11 @@ static int Lnexti(lua_State *L)
         return 0;
     }
     // Stack: [mt, buckets, bucket, inst_table, fields, i2, next_fieldname]
-    lua_rawgeti(L, -4, lua_tonumber(L, -2));
-    // Stack: [mt, buckets, bucket, inst_table, fields, i2, next_fieldname, value]
-    return 3;
+    lua_pop(L, 1);
+    // Stack: [mt, buckets, bucket, inst_table, fields, i2]
+    lua_rawgeti(L, -3, lua_tonumber(L, -1));
+    // Stack: [mt, buckets, bucket, inst_table, fields, i2, value]
+    return 2;
 }
 
 static int Lipairs(lua_State *L)
@@ -308,12 +309,48 @@ static int Lipairs(lua_State *L)
     return 3;
 }
 
+static int Lnext(lua_State *L)
+{
+    lua_getmetatable(L, 1);
+    // Stack: [mt]
+    lua_getfield(L, -1, "__instances");
+    // Stack: [mt, buckets]
+    lua_rawgeti(L, -1, *((lua_Integer*)lua_touserdata(L, 1)));
+    // Stack: [mt, buckets, bucket]
+    lua_pushvalue(L, 1);
+    // Stack: [mt, buckets, bucket, inst_udata]
+    lua_rawget(L, -2);
+    // Stack: [mt, buckets, bucket, inst_table]
+    lua_getfield(L, -4, "__field_positions");
+    // Stack: [mt, buckets, bucket, inst_table, fields]
+    lua_pushvalue(L, 2);
+    // Stack: [mt, buckets, bucket, inst_table, fields, k]
+    if (lua_next(L, -2) == 0) {
+        return 0;
+    }
+    // Stack: [mt, buckets, bucket, inst_table, fields, k2, next_i]
+    lua_rawgeti(L, -4, lua_tonumber(L, -1));
+    // Stack: [mt, buckets, bucket, inst_table, fields, k2, next_i, value]
+    return 3;
+}
+
+static int Lpairs(lua_State *L)
+{
+    lua_pushcfunction(L, Lnext);
+    // Stack: [Lnexti]
+    lua_pushvalue(L, 1);
+    // Stack: [Lnexti, inst_udata]
+    lua_pushnil(L);
+    // Stack: [Lnexti, inst_udata, nil]
+    return 3;
+}
+
 static const luaL_Reg R[] =
 {
     { "__len", Llen},
     { "__index", Lindex},
     { "__ipairs", Lipairs},
-    { "new", Lcreate_instance},
+    { "__pairs", Lpairs},
     { NULL, NULL}
 };
 
@@ -355,6 +392,20 @@ static int Lmake_class(lua_State *L)
     // Stack: [CLS, __fields]
     lua_setfield(L, -2, "__fields");
     // Stack: [CLS]
+    
+    size_t n = lua_objlen(L, 1);
+    lua_createtable(L, 0, n);
+    // Stack: [CLS, __field_positions]
+    lua_pushnil(L);
+    while (lua_next(L, 1) != 0) {
+        // Stack: [CLS, __field_positions, i, fieldname]
+        lua_pushvalue(L, -2);
+        // Stack: [CLS, __field_positions, i, fieldname, i]
+        lua_settable(L, -4);
+        // Stack: [CLS, __field_positions, i]
+    }
+    lua_setfield(L, -2, "__field_positions");
+    // Stack: [CLS]
 
     // If methods were passed in, copy them over
     if (n_args > 1) {
diff --git a/test.lua b/test.lua
index b577bcc..50bc08e 100644
--- a/test.lua
+++ b/test.lua
@@ -62,6 +62,10 @@ test("Instantiating class", function()
     v = assert(Vec(1,3))
 end)
 
+test("Testing # operator", function()
+    assert(#v == 2)
+end)
+
 test("Testing method", function()
     assert(v:len2() == 10)
 end)