feat: better error messages

pkg/saccharine/token/token.go

@@ -4,26 +4,19 @@ package token
 type Type int
 
 const (
-	// Denotes the '(' token.
-	OpenParen Type = iota
-	// Denotes the ')' token.
-	CloseParen
-	// Denotes an alpha-numeric variable.
-	Atom
-	// Denotes the '/' token.
-	Slash
-	// Denotes the '.' token.
-	Dot
+	OpenParen  Type = iota // Denotes the '(' token.
+	CloseParen             // Denotes the ')' token.
+	Atom                   // Denotes an alpha-numeric variable.
+	Slash                  // Denotes the '/' token.
+	Dot                    // Denotes the '.' token.
+	Newline                // Denotes a new-line.
 )
 
 // A representation of a token in source code.
 type Token struct {
-	// Where the token begins in the source text.
-	Index int
-	// What type the token is.
-	Type Type
-	// The value of the token.
-	Value string
+	Index int    // Where the token begins in the source text.
+	Type  Type   // What type the token is.
+	Value string // The value of the token.
 }
 
 func NewOpenParen(index int) *Token {
@@ -46,6 +39,10 @@ func NewAtom(name string, index int) *Token {
 	return &Token{Type: Atom, Index: index, Value: name}
 }
 
+func NewNewline(index int) *Token {
+	return &Token{Type: Newline, Index: index, Value: "\\n"}
+}
+
 func Name(typ Type) string {
 	switch typ {
 	case OpenParen:
@@ -58,6 +55,8 @@ func Name(typ Type) string {
 		return "."
 	case Atom:
 		return "ATOM"
+	case Newline:
+		return "\\n"
 	default:
 		return "?"
 	}