Improve identifier parsing checks

parser/src/parsing/common.rs

@@ -17,7 +17,10 @@ pub fn parse_identifier(input: &str) -> IResult<&str, &str> {
     let (_, first) = peek(anychar)(input)?;
     if first.is_alphabetic() || first == '_' {
         take_while(|c: char| {
-            is_alphanumeric(c as u8) || c == '_'
+            match c {
+                'a'..='z' | 'A'..='Z' | '_' | '0'..='9' => true,
+                _ => false
+            }
         })(input)
     } else {
         Err(nom::Err::Error(make_error(