first codegen prototype

include/parser/lexer.hpp

@@ -47,13 +47,13 @@ inline bool operator!=(char c, TokenType t)
 
 struct Token
 {
-    TokenType token;
-    long int_number;
+    TokenType token = TokenType::Unknown;
+    long int_number = 0;
     // null-terminated
     StringView string;
-    long line_number;
-    long offset_start;
-    long offset_end;
+    long line_number = 0;
+    long offset_start = 0;
+    long offset_end = 0;
 public:
     Token(TokenType t) : token(t) {}
     Token(TokenType t, long lnumber, long soffset, long eoffset)