public static bool ResolveToFunctionIndex(this CompilerIO self, Slice slice, out int index)
        {
            var source = self.parser.tokenizer.source;

            for (var i = 0; i < self.chunk.functions.count; i++)
            {
                var f = self.chunk.functions.buffer[i];
                if (
                    CompilerHelper.IsFunctionVisible(self.chunk, i, self.functionsStartIndex) &&
                    CompilerHelper.AreEqual(source, slice, f.name)
                    )
                {
                    index = i;
                    return(true);
                }
            }

            index = 0;
            return(false);
        }