diff --git a/src/nasal_lexer.cpp b/src/nasal_lexer.cpp
index facfe13..c745cef 100644
--- a/src/nasal_lexer.cpp
+++ b/src/nasal_lexer.cpp
@@ -11,11 +11,11 @@ bool lexer::skip(char c) {
 }
 
 bool lexer::is_id(char c) {
-    return (c=='_') || ('a'<=c && c<='z') || ('A'<=c && c<='Z') || (c<0);   
+    return (c=='_') || std::isalpha(c) || (c<0);   
 }
 
 bool lexer::is_hex(char c) {
-    return ('0'<=c && c<='9') || ('a'<=c && c<='f') || ('A'<=c && c<='F');
+    return std::isdigit(c) || ('a'<=c && c<='f') || ('A'<=c && c<='F');
 }
 
 bool lexer::is_oct(char c) {
@@ -23,7 +23,7 @@ bool lexer::is_oct(char c) {
 }
 
 bool lexer::is_dec(char c) {
-    return '0'<=c && c<='9';
+    return std::isdigit(c);
 }
 
 bool lexer::is_str(char c) {
diff --git a/test/httptest.nas b/test/httptest.nas
index 2fac7f8..be0f6bb 100644
--- a/test/httptest.nas
+++ b/test/httptest.nas
@@ -48,28 +48,31 @@ http.establish("127.0.0.1",8080);
 
 var highlight_style="
 <style>
-    body{
+    body {
         background: #303030;
     }
-    pre{
+    pre {
         background: #303030;
         font-family: 'Courier New', Courier, monospace;
         font-size: small;
         color: #d4d4d4;
     }
-    code{
+    code {
         color: white;
         font-family: 'Courier New', Courier, monospace;
         font-size: small;
         text-align: left;
     }
-    code.key{color: #f895e7;}
-    code.id{color: #8abef0;}
-    code.opr{color: #f895e7;}
-    code.brace{color: #eafd70;}
-    code.str{color: #a5ffd0;}
-    code.num{color: #ff9a41;}
-    code.note{color: #808080;}
+    code.key {
+        color: #f895e7;
+        font-weight: bold;
+    }
+    code.id {color: #8abef0;}
+    code.opr {color: #f895e7;}
+    code.brace {color: #eafd70;}
+    code.str {color: #a5ffd0;}
+    code.num {color: #ff9a41;}
+    code.note {color: #808080;}
 </style>";
 
 var html_read_file=func(filename){