Add: string.char

src/Lua/Standard/OpenLibExtensions.cs

@@ -78,6 +78,7 @@ public static class OpenLibExtensions
 
     static readonly LuaFunction[] stringFunctions = [
         ByteFunction.Instance,
+        CharFunction.Instance,
         LenFunction.Instance,
         LowerFunction.Instance,
         RepFunction.Instance,

src/Lua/Standard/Text/CharFunction.cs

@@ -0,0 +1,30 @@
+
+using Lua.Internal;
+
+namespace Lua.Standard.Text;
+
+public sealed class CharFunction : LuaFunction
+{
+    public override string Name => "char";
+    public static readonly CharFunction Instance = new();
+
+    protected override ValueTask<int> InvokeAsyncCore(LuaFunctionExecutionContext context, Memory<LuaValue> buffer, CancellationToken cancellationToken)
+    {
+        if (context.ArgumentCount == 0)
+        {
+            buffer.Span[0] = "";
+            return new(1);
+        }
+
+        var strBuffer = new PooledArray<char>(context.ArgumentCount);
+        for (int i = 0; i < context.ArgumentCount; i++)
+        {
+            var arg = context.GetArgument<double>(i);
+            LuaRuntimeException.ThrowBadArgumentIfNumberIsNotInteger(context.State, this, i + 1, arg);
+            strBuffer[i] = (char)arg;
+        }
+
+        buffer.Span[0] = strBuffer.AsSpan().ToString();
+        return new(1);
+    }
+}