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/* jshint esversion: 6 */
"use strict";
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 */
let str = "";
lapi.lua_getglobal(L, "tostring");
for (let i = 1; i <= n; i++) {
lapi.lua_pushvalue(L, -1); /* function to be called */
lapi.lua_pushvalue(L, i); /* value to print */
lapi.lua_call(L, 1, 1);
let s = lapi.lua_tolstring(L, -1, null);
if (s === null)
throw new Error("'tostring' must return a string to 'print");
if (i > 1) s = `\t${s}`;
str = `${str}${s}`;
lapi.lua_pop(L, 1);
}
console.log(str);
return 0;
};
const luaB_tostring = function(L) {
lauxlib.luaL_checkany(L, 1);
lauxlib.luaL_tolstring(L, 1, null);
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,
"getmetatable": luaB_getmetatable,
"setmetatable": luaB_setmetatable,
};
const luaopen_base = function(L) {
/* open lib into global table */
lapi.lua_pushglobaltable(L);
lauxlib.luaL_setfuncs(L, base_funcs, 0);
/* set global _G */
lapi.lua_pushvalue(L, -1);
lapi.lua_setfield(L, -2, "_G");
/* set global _VERSION */
lapi.lua_pushliteral(L, lua.LUA_VERSION);
lapi.lua_setfield(L, -2, "_VERSION");
return true;
};
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;
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