lstrlib, string.len

1 files changed, 36 insertions, 0 deletions

diff --git a/src/lstrlib.js b/src/lstrlib.js
new file mode 100644
index 0000000..194d6ba
--- /dev/null
+++ b/src/lstrlib.js
@@ -0,0 +1,36 @@
+"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 TS      = lua.thread_status;
+
+const str_len = function(L) {
+    lauxlib.luaL_checkstring(L, 1);
+    lapi.lua_pushinteger(L, lapi.lua_tostring(L, 1).length);
+    return 1;
+};
+
+const strlib = {
+    "len": str_len
+};
+
+const createmetatable = function(L) {
+    lapi.lua_createtable(L, 0, 1);  /* table to be metatable for strings */
+    lapi.lua_pushliteral(L, "");  /* dummy string */
+    lapi.lua_pushvalue(L, -2);  /* copy table */
+    lapi.lua_setmetatable(L, -2);  /* set table as metatable for strings */
+    lapi.lua_pop(L, 1);  /* pop dummy string */
+    lapi.lua_pushvalue(L, -2);  /* get string library */
+    lapi.lua_setfield(L, -2, "__index");  /* metatable.__index = string */
+    lapi.lua_pop(L, 1);  /* pop metatable */  
+};
+
+const luaopen_string = function(L) {
+    lauxlib.luaL_newlib(L, strlib);
+    createmetatable(L);
+    return 1;
+};
\ No newline at end of file