setmetatable, getmetatable

6 files changed, 183 insertions, 33 deletions

diff --git a/README.md b/README.md
index 3407512..19306fe 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,7 @@
     - [x] lua_getfield
     - [x] lua_getglobal
     - [x] lua_getmetatable
+    - [x] lua_setmetatable
     - [x] lua_pushglobaltable
     - [x] lua_pushliteral
     - [x] lua_rawget
@@ -124,7 +125,6 @@
     - [ ] lua_sethook
     - [ ] lua_seti
     - [ ] lua_setlocal
-    - [ ] lua_setmetatable
     - [ ] lua_setupvalue
     - [ ] lua_setuservalue
     - [ ] lua_status
@@ -142,6 +142,7 @@
     - [x] luaL_newstate
     - [x] luaL_typename
     - [x] luaL_checkany
+    - [x] luaL_checktype
     - [x] luaL_callmeta
     - [x] luaL_getmetafield
     - [x] luaL_setfuncs
@@ -167,7 +168,6 @@
     - [ ] luaL_checknumber
     - [ ] luaL_checkoption
     - [ ] luaL_checkstring
-    - [ ] luaL_checktype
     - [ ] luaL_checkudata
     - [ ] luaL_checkversion
     - [ ] luaL_dofile
@@ -204,6 +204,8 @@
 - [ ] Standard library
     - [x] tostring
     - [x] print
+    - [x] getmetatable
+    - [x] setmetatable
     - [ ] ...
 - [ ] Debug (errors)
 - [ ] DOM API binding
diff --git a/src/lapi.js b/src/lapi.js
index ece02e0..e1e548d 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -260,6 +260,33 @@ const lua_setglobal = function(L, name) {
     auxsetstr(L, L.l_G.l_registry.value.array[lua.LUA_RIDX_GLOBALS - 1], name);
 };
 
+const lua_setmetatable = function(L, objindex) {
+    assert(1 < L.top - L.ci.funcOff, "not enough elements in the stack");
+    let mt;
+    let obj = index2addr(L, objindex);
+    if (L.stack[L.top - 1].ttisnil())
+        mt = null;
+    else {
+        assert(L.stack[L.top - 1].ttistable(), "table expected");
+        mt = L.stack[L.top - 1];
+    }
+
+    switch (obj.ttnov()) {
+        case CT.LUA_TUSERDATA:
+        case CT.LUA_TTABLE: {
+            obj.metatable = mt;
+            break;
+        }
+        default: {
+            L.l_G.mt[obj.ttnov()] = mt;
+            break;
+        }
+    }
+
+    L.top--;
+    return true;
+};
+
 const lua_settable = function(L, idx) {
     assert(2 < L.top - L.ci.funcOff, "not enough elements in the stack");
 
@@ -562,4 +589,6 @@ module.exports.lua_pushglobaltable = lua_pushglobaltable;
 module.exports.lua_setfield        = lua_setfield;
 module.exports.lua_getfield        = lua_getfield;
 module.exports.lua_getglobal       = lua_getglobal;
-module.exports.lua_getmetatable    = lua_getmetatable;
\ No newline at end of file
+module.exports.lua_getmetatable    = lua_getmetatable;
+module.exports.lua_setmetatable    = lua_setmetatable;
+module.exports.lua_settop          = lua_settop;
\ No newline at end of file
diff --git a/src/lauxlib.js b/src/lauxlib.js
index 6db0aae..a1f9d64 100644
--- a/src/lauxlib.js
+++ b/src/lauxlib.js
@@ -13,7 +13,27 @@ const LUA_LOADED_TABLE = "_LOADED"
 const panic = function(L) {
     console.log(`PANIC: unprotected error in call to Lua API (...)`);
     return 0;
-}
+};
+
+const typeerror = function(L, arg, tname) {
+    let typearg;
+    if (luaL_getmetafield(L, arg, "__name") === CT.LUA_TSTRING)
+        typearg = lapi.lua_tostring(L, -1);
+    else if (lapi.lua_type(L, arg) === CT.LUA_TLIGHTUSERDATA)
+        typearg = "light userdata";
+    else
+        typearg = luaL_typename(L, arg);
+
+    throw new Error(`${tname} expected, got ${typearg}`);
+
+    // TODO:
+    // let msg = lua_pushstring(L, `${tname} expected, got ${typearg}`);
+    // return luaL_argerror(L, arg, msg);
+};
+
+const tag_error = function(L, arg, tag) {
+    typeerror(L, arg, lapi.lua_typename(L, tag));
+};
 
 const luaL_newstate = function() {
     let L = lstate.lua_newstate();
@@ -26,11 +46,20 @@ const luaL_typename = function(L, i) {
     return lapi.lua_typename(L, lapi.lua_type(L, i));
 };
 
+const luaL_argcheck = function(L, cond, arg, extramsg) {
+    if (!cond) throw new Error("bad argument"); // TODO: luaL_argerror
+};
+
 const luaL_checkany = function(L, arg) {
     if (lapi.lua_type(L, arg) === CT.LUA_TNONE)
         throw new Error("value expected"); // TODO: luaL_argerror(L, arg, "value expected");
 };
 
+const luaL_checktype = function(L, arg, t) {
+    if (lapi.lua_type(L, arg) !== t)
+        tag_error(L, arg, t);
+};
+
 const luaL_getmetafield = function(L, obj, event) {
     if (!lapi.lua_getmetatable(L, obj))
         return CT.LUA_TNIL;
@@ -157,6 +186,7 @@ const luaL_checkstack = function(L, space, msg) {
 module.exports.luaL_newstate     = luaL_newstate;
 module.exports.luaL_typename     = luaL_typename;
 module.exports.luaL_checkany     = luaL_checkany;
+module.exports.luaL_checktype    = luaL_checktype;
 module.exports.luaL_callmeta     = luaL_callmeta;
 module.exports.luaL_getmetafield = luaL_getmetafield;
 module.exports.luaL_requiref     = luaL_requiref;
@@ -164,4 +194,5 @@ module.exports.luaL_getsubtable  = luaL_getsubtable;
 module.exports.luaL_setfuncs     = luaL_setfuncs;
 module.exports.luaL_checkstack   = luaL_checkstack;
 module.exports.LUA_LOADED_TABLE  = LUA_LOADED_TABLE;
-module.exports.luaL_tolstring    = luaL_tolstring;
\ No newline at end of file
+module.exports.luaL_tolstring    = luaL_tolstring;
+module.exports.luaL_argcheck     = luaL_argcheck;
\ No newline at end of file
diff --git a/src/lbaselib.js b/src/lbaselib.js
index b046f67..12c28fe 100644
--- a/src/lbaselib.js
+++ b/src/lbaselib.js
@@ -6,6 +6,7 @@ const assert  = require('assert');
 const lua     = require('./lua.js');
 const lapi    = require('./lapi.js');
 const lauxlib = require('./lauxlib.js');
+const CT      = lua.constant_types;
 
 const luaB_print = function(L) {
     let n = lapi.lua_gettop(L); /* number of arguments */
@@ -35,9 +36,32 @@ const luaB_tostring = function(L) {
     return true;
 };
 
+const luaB_getmetatable = function(L) {
+    lauxlib.luaL_checkany(L, 1);
+    if (!lapi.lua_getmetatable(L, 1)) {
+        lapi.lua_pushnil(L);
+        return true;  /* no metatable */
+    }
+    lauxlib.luaL_getmetafield(L, 1, "__metatable");
+    return true;  /* returns either __metatable field (if present) or metatable */
+};
+
+const luaB_setmetatable = function(L) {
+    let t = lapi.lua_type(L, 2);
+    lauxlib.luaL_checktype(L, 1, CT.LUA_TTABLE);
+    lauxlib.luaL_argcheck(L, t === CT.LUA_TNIL || t === CT.LUA_TTABLE, 2, "nil or table expected");
+    if (lauxlib.luaL_getmetafield(L, 1, "__metatable") !== CT.LUA_TNIL)
+        throw new Error("cannot change a protected metatable");
+    lapi.lua_settop(L, 2);
+    lapi.lua_setmetatable(L, 1);
+    return true;
+};
+
 const base_funcs = {
-    "print":    luaB_print,
-    "tostring": luaB_tostring,
+    "print":        luaB_print,
+    "tostring":     luaB_tostring,
+    "getmetatable": luaB_getmetatable,
+    "setmetatable": luaB_setmetatable,
 };
 
 const luaopen_base = function(L) {
@@ -53,6 +77,8 @@ const luaopen_base = function(L) {
     return true;
 };
 
-module.exports.luaB_tostring = luaB_tostring;
-module.exports.luaB_print    = luaB_print;
-module.exports.luaopen_base  = luaopen_base;
+module.exports.luaB_tostring     = luaB_tostring;
+module.exports.luaB_print        = luaB_print;
+module.exports.luaB_getmetatable = luaB_getmetatable;
+module.exports.luaB_setmetatable = luaB_setmetatable;
+module.exports.luaopen_base      = luaopen_base;
diff --git a/tests/lapi.js b/tests/lapi.js
index 561b774..30366d5 100644
--- a/tests/lapi.js
+++ b/tests/lapi.js
@@ -490,27 +490,4 @@ test('lua_settable, lua_gettable', function (t) {
         "value",
         "Correct element(s) on the stack"
     );
-});
-
-
-test('print', function (t) {
-    let luaCode = `
-        print("hello", "world", 123)
-    `, L;
-    
-    t.plan(1);
-
-    t.doesNotThrow(function () {
-
-        let bc = toByteCode(luaCode).dataView;
-
-        L = lauxlib.luaL_newstate();
-
-        linit.luaL_openlibs(L);
-
-        lapi.lua_load(L, bc, "test-lua_load")
-
-        lapi.lua_call(L, 0, 1);
-
-    }, "JS Lua program ran without error");
 });
\ No newline at end of file
diff --git a/tests/lbaselib.js b/tests/lbaselib.js
new file mode 100644
index 0000000..3ddec2d
--- /dev/null
+++ b/tests/lbaselib.js
@@ -0,0 +1,85 @@
+/*jshint esversion: 6 */
+"use strict";
+
+const test       = require('tape');
+const beautify   = require('js-beautify').js_beautify;
+
+const tests      = require("./tests.js");
+const getState   = tests.getState;
+const toByteCode = tests.toByteCode;
+
+const VM         = require("../src/lvm.js");
+const ldo        = require("../src/ldo.js");
+const lapi       = require("../src/lapi.js");
+const lauxlib    = require("../src/lauxlib.js");
+const lua        = require('../src/lua.js');
+const linit      = require('../src/linit.js');
+const CT         = lua.constant_types;
+
+
+test('print', function (t) {
+    let luaCode = `
+        print("hello", "world", 123)
+    `, L;
+    
+    t.plan(1);
+
+    t.doesNotThrow(function () {
+
+        let bc = toByteCode(luaCode).dataView;
+
+        L = lauxlib.luaL_newstate();
+
+        linit.luaL_openlibs(L);
+
+        lapi.lua_load(L, bc, "test-print");
+
+        lapi.lua_call(L, 0, 1);
+
+    }, "JS Lua program ran without error");
+});
+
+
+test('setmetatable, getmetatable', function (t) {
+    let luaCode = `
+        local mt = {
+            __index = function ()
+                print("hello")
+                return "hello"
+            end
+        }
+
+        local t = {}
+
+        setmetatable(t, mt);
+
+        return t[1], getmetatable(t)
+    `, L;
+    
+    t.plan(3);
+
+    t.doesNotThrow(function () {
+
+        let bc = toByteCode(luaCode).dataView;
+
+        L = lauxlib.luaL_newstate();
+
+        linit.luaL_openlibs(L);
+
+        lapi.lua_load(L, bc, "test-setmetatable-getmetatable");
+
+        lapi.lua_call(L, 0, -1);
+
+    }, "JS Lua program ran without error");
+
+    t.strictEqual(
+        lapi.lua_tostring(L, -2),
+        "hello",
+        "Correct element(s) on the stack"
+    );
+
+    t.ok(
+        lapi.lua_istable(L, -1),
+        "Correct element(s) on the stack"
+    );
+});
\ No newline at end of file