diff --git a/lexer/lexer.go b/lexer/lexer.go
index ecd1d3e..5ac643d 100644
--- a/lexer/lexer.go
+++ b/lexer/lexer.go
@@ -9,7 +9,7 @@ type Lexer struct {
 	current_char  byte
 }
 
-func new(input string) *Lexer {
+func New(input string) *Lexer {
 	l := &Lexer{input: input}
 	l.read_char()
 	return l
@@ -67,7 +67,7 @@ func is_digit(ch byte) bool {
 	return '0' <= ch && ch <= '9'
 }
 
-func (lexer *Lexer) next_token() token.Token {
+func (lexer *Lexer) NextToken() token.Token {
 	var tok token.Token
 	lexer.skip_whitespace()
 
diff --git a/lexer/lexer_test.go b/lexer/lexer_test.go
index 7a41817..2e6f8d5 100644
--- a/lexer/lexer_test.go
+++ b/lexer/lexer_test.go
@@ -114,9 +114,9 @@ func TestNextToken(t *testing.T) {
 		{token.EOF, ""},
 	}
 
-	l := new(input)
+	l := New(input)
 	for i, tt := range tests {
-		tok := l.next_token()
+		tok := l.NextToken()
 		if tok.Type != tt.expectedType {
 			t.Fatalf("test[%d] - tokentype wrong. expected=%q, got=%q", i, tt.expectedType, tok.Type)
 		}
diff --git a/repl/repl.go b/repl/repl.go
index 0099bab..1c36ba7 100644
--- a/repl/repl.go
+++ b/repl/repl.go
@@ -1,31 +1,31 @@
-package repl
-
-import (
-	"bufio"
-	"fmt"
-	"io"
-
-	"monkey/lexer"
-	"monkey/token"
-)
-
-const PROMPT = ">> "
-
-func Start(in io.Reader, out io.Writer){
-	scanner := bufio.NewScanner(in)
-
-	for {
-		fmt.Fprintf(out, PROMPT)
-		scanned := scanner.Scan()
-		if !scanned{
-			return
-		}
-
-		line := scanner.Text()
-		l := lexer.new(line)
-
-		for tok := l.next_token(); tok.Type != token.EOF; tok = l.next_token(){
-			fmt.Fprintf(out, "%+v\n", tok)
-		}
-	}
-}
+package repl
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+
+	"monkey/lexer"
+	"monkey/token"
+)
+
+const PROMPT = ">> "
+
+func Start(in io.Reader, out io.Writer) {
+	scanner := bufio.NewScanner(in)
+
+	for {
+		fmt.Fprintf(out, PROMPT)
+		scanned := scanner.Scan()
+		if !scanned {
+			return
+		}
+
+		line := scanner.Text()
+		l := lexer.New(line)
+
+		for tok := l.NextToken(); tok.Type != token.EOF; tok = l.NextToken() {
+			fmt.Fprintf(out, "%+v\n", tok)
+		}
+	}
+}