Updated spec.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/yuescript/yue_compiler.cpp b/src/yuescript/yue_compiler.cpp
index 4dd3583..75f4787 100644
--- a/src/yuescript/yue_compiler.cpp
+++ b/src/yuescript/yue_compiler.cpp
@@ -1360,10 +1360,10 @@ private:
                 std::ostringstream buf;
                 for (auto it = uname->m_begin.m_it; it != uname->m_end.m_it; ++it) {
                         auto ch = *it;
-                        if (ch > 255) {
-                                buf << "_u"sv << std::hex << static_cast<int>(ch);
-                        } else {
+                        if (ch <= 0x7F && ((ch == '_') || ((ch | 0x20) >= 'a' && (ch | 0x20) <= 'z') || (ch >= '0' && ch <= '9'))) {
                                 buf << static_cast<char>(ch);
+                        } else {
+                                buf << "_u"sv << std::hex << static_cast<uint32_t>(ch);
                         }
                 }
                 return buf.str();