Add the error code to the diagnostic

docs/examples/hello_world.srn

@@ -1,5 +1,5 @@
 (def main
-  (fn () 4))
+  (fn () 4)))
 
 (def main1 (fn (v y n) 3))
 ht

include/serene/errors/constants.h

@@ -25,6 +25,7 @@
 #ifndef SERENE_ERRORS_CONSTANTS_H
 #define SERENE_ERRORS_CONSTANTS_H
 
+#include <llvm/Support/FormatVariadic.h>
 #include <map>
 #include <string>
 
@@ -32,7 +33,7 @@ namespace serene {
 namespace errors {
 
 enum ErrID {
-  E0000,
+  E0000 = 0,
   E0001,
   E0002,
   E0003,
@@ -56,6 +57,8 @@ struct ErrorVariant {
 
   ErrorVariant(ErrID id, std::string desc, std::string longDesc)
       : id(id), description(desc), longDescription(longDesc){};
+
+  std::string getErrId() { return llvm::formatv("E{0:d}", id); };
 };
 
 static ErrorVariant

src/serene/diagnostics.cpp

@@ -84,18 +84,22 @@ void Diagnostic::print(llvm::raw_ostream &os, llvm::StringRef prefix) {
   llvm::WithColor s(os, llvm::raw_ostream::SAVEDCOLOR, true, false, mode);
 
   s << "[";
+  if (err) {
+    writeColorByType(os, err->getErrId());
+  }
+  s << "] ";
   writeColorByType(os, getPrefix(prefix));
-  s << "]: ";
+  s << ": ";
 
   if (err) {
-    s << err->description << "\n";
+    s << err->description << '\n';
   }
 
   if (message != "") {
     s.changeColor(llvm::raw_ostream::Colors::YELLOW);
-    s << "With message: ";
+    s << "With message";
     s.resetColor();
-    s << message << "\n";
+    s << ": " << message << "\n";
   }
 
   s << "In ns '";

src/serene/reader/reader.cpp

@@ -222,7 +222,14 @@ exprs::Node Reader::readSymbol() {
   if (!this->isValidForIdentifier(*c) || isEndOfBuffer(c) || isspace(*c)) {
     advance();
     loc = LocationRange(getCurrentLocation());
-    ctx.diagEngine->emitSyntaxError(loc, errors::InvalidCharacterForSymbol);
+    std::string msg;
+
+    if (*c == ')') {
+      msg = "An extra ')' is detected.";
+    }
+
+    ctx.diagEngine->emitSyntaxError(loc, errors::InvalidCharacterForSymbol,
+                                    msg);
     exit(1);
   }