feat: tokenizer accepts braces, line terminator, and equal sign

pkg/saccharine/stringify.go

@@ -1,31 +1,39 @@
 package saccharine
 
 import (
+	"fmt"
 	"strings"
 
 	"git.maximhutz.com/max/lambda/pkg/saccharine/ast"
 )
 
-type stringifyVisitor struct{}
-
-func (v stringifyVisitor) VisitAtom(n *ast.Atom) string {
+func stringifyAtom(n *ast.Atom) string {
 	return n.Name
 }
 
-func (v stringifyVisitor) VisitAbstraction(n *ast.Abstraction) string {
-	return "\\" + strings.Join(n.Parameters, " ") + "." + ast.Visit(v, n.Body)
+func stringifyAbstraction(n *ast.Abstraction) string {
+	return "\\" + strings.Join(n.Parameters, " ") + "." + Stringify(n.Body)
 }
 
-func (v stringifyVisitor) VisitApplication(n *ast.Application) string {
-	arguments := []string{ast.Visit(v, n.Abstraction)}
+func stringifyApplication(n *ast.Application) string {
+	arguments := []string{Stringify(n.Abstraction)}
 
 	for _, argument := range n.Arguments {
-		arguments = append(arguments, ast.Visit(v, argument))
+		arguments = append(arguments, Stringify(argument))
 	}
 
 	return "(" + strings.Join(arguments, " ") + ")"
 }
 
 func Stringify(n ast.Expression) string {
-	return ast.Visit(&stringifyVisitor{}, n)
+	switch n := n.(type) {
+	case *ast.Atom:
+		return stringifyAtom(n)
+	case *ast.Abstraction:
+		return stringifyAbstraction(n)
+	case *ast.Application:
+		return stringifyApplication(n)
+	default:
+		panic(fmt.Errorf("unknown expression type: %v", n))
+	}
 }