From dbbbb1a029fa3d6ad346426bee3310191e0dd285 Mon Sep 17 00:00:00 2001
From: Benoit Giannangeli <benoit.giannangeli@boursorama.fr>
Date: Wed, 15 Mar 2017 08:14:30 +0100
Subject: utf8.char

---
 README.md         |  6 ++++++
 src/lutf8lib.js   | 28 +++++++++++++++++++++++++++-
 tests/lutf8lib.js | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 21f92fe..573288e 100644
--- a/README.md
+++ b/README.md
@@ -234,6 +234,12 @@
     - [ ] io
     - [ ] Debug
     - [ ] utf8
+        - [x] utf8.char
+        - [x] utf8.codepoint
+        - [x] utf8.offset
+        - [ ] utf8.charpattern
+        - [ ] utf8.codes
+        - [ ] utf8.len
 - [ ] Run [Lua test suite](https://github.com/lua/tests)
 - [ ] DOM API binding
 
diff --git a/src/lutf8lib.js b/src/lutf8lib.js
index f2c7f6b..6ebbec8 100644
--- a/src/lutf8lib.js
+++ b/src/lutf8lib.js
@@ -50,6 +50,31 @@ const utf8_decode = function(s, val) {
     };
 };
 
+const pushutfchar = function(L, arg) {
+    let code = lauxlib.luaL_checkinteger(L, arg);
+    lauxlib.luaL_argcheck(L, 0 <= code && code <= MAXUNICODE, arg, "value out of range");
+    lapi.lua_pushstring(L, `${String.fromCharCode(code)}`);
+};
+
+/*
+** utfchar(n1, n2, ...)  -> char(n1)..char(n2)...
+*/
+const utfchar = function(L) {
+    let n = lapi.lua_gettop(L);  /* number of arguments */
+    if (n === 1)  /* optimize common case of single char */
+        pushutfchar(L, 1);
+    else {
+        let b = new lauxlib.luaL_Buffer();
+        lauxlib.luaL_buffinit(L, b);
+        for (let i = 1; i <= n; i++) {
+            pushutfchar(L, i);
+            lauxlib.luaL_addvalue(b);
+        }
+        lauxlib.luaL_pushresult(b);
+    }
+    return 1;
+};
+
 /*
 ** offset(s, n, [i])  -> index where n-th character counting from
 **   position 'i' starts; 0 means character at 'i'.
@@ -128,8 +153,9 @@ const codepoint = function(L) {
 };
 
 const funcs = {
+    "char":      utfchar,
     "codepoint": codepoint,
-    "offset":    byteoffset
+    "offset":    byteoffset,
 };
 
 /* pattern to match a single UTF-8 character */
diff --git a/tests/lutf8lib.js b/tests/lutf8lib.js
index edfae56..7033a57 100644
--- a/tests/lutf8lib.js
+++ b/tests/lutf8lib.js
@@ -80,4 +80,36 @@ test('utf8.codepoint', function (t) {
         "Correct element(s) on the stack"
     );
 
+});
+
+
+test('utf8.char', function (t) {
+    let luaCode = `
+        return utf8.char(40, 32, 865, 176, 32, 860, 662, 32, 865, 176, 32, 41)
+    `, L;
+    
+    t.plan(3);
+
+    t.doesNotThrow(function () {
+
+        L = lauxlib.luaL_newstate();
+
+        linit.luaL_openlibs(L);
+
+        lauxlib.luaL_loadstring(L, luaCode);
+
+    }, "Lua program loaded without error");
+
+    t.doesNotThrow(function () {
+
+        lapi.lua_call(L, 0, -1);
+
+    }, "Lua program ran without error");
+
+    t.strictEqual(
+        lapi.lua_tostring(L, -1),
+        "( ͡° ͜ʖ ͡° )",
+        "Correct element(s) on the stack"
+    );
+
 });
\ No newline at end of file
-- 
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