public LinkedFile ReadLinkedFile(string fullIdentifier)
        {
            var builtin = builtins?.GetBuiltinIfExists(fullIdentifier);

            if (builtin != null)
            {
                return(builtin);
            }

            var fullPath = fullIdentifier;
            var fileText = File.ReadAllText(fullPath);

            return(new ParsedFile(fullPath, fileText, Path.GetExtension(fullPath) == ".lsyslib", builtins.AllBuiltins()));
        }
        public LinkedFile ReadLinkedFile(string fullIdentifier)
        {
            var builtin = builtins?.GetBuiltinIfExists(fullIdentifier);

            if (builtin != null)
            {
                return(builtin);
            }
            if (!fileContents.ContainsKey(fullIdentifier))
            {
                return(null);
            }
            var fileText = fileContents[fullIdentifier];

            return(new ParsedFile(fullIdentifier, fileText, Path.GetExtension(fullIdentifier) == ".lsyslib", builtins.AllBuiltins()));
        }