From 1ec5781848e24ec3757c23c80fa324ae378b63d9 Mon Sep 17 00:00:00 2001
From: Akos <akos@Akoss-MacBook-Air.local>
Date: Sun, 6 Oct 2024 11:00:08 +0200
Subject: [PATCH 1/2] Add additional tokens

---
 lexer/lexer.go      | 12 ++++++++++++
 lexer/lexer_test.go | 16 +++++++++++++++-
 token/token.go      | 11 +++++++++--
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/lexer/lexer.go b/lexer/lexer.go
index 1342ac9..5f31b05 100644
--- a/lexer/lexer.go
+++ b/lexer/lexer.go
@@ -20,10 +20,22 @@ func (l *Lexer) NextToken() token.Token {
 		tok = newToken(token.COMMA, l.ch)
 	case '+':
 		tok = newToken(token.PLUS, l.ch)
+	case '-':
+		tok = newToken(token.MINUS, l.ch)
+	case '*':
+		tok = newToken(token.ASTERISK, l.ch)
+	case '/':
+		tok = newToken(token.SLASH, l.ch)
+	case '<':
+		tok = newToken(token.LT, l.ch)
+	case '>':
+		tok = newToken(token.GT, l.ch)
 	case '{':
 		tok = newToken(token.LBRACE, l.ch)
 	case '}':
 		tok = newToken(token.RBRACE, l.ch)
+	case '!':
+		tok = newToken(token.BANG, l.ch)
 	case 0:
 		tok.Literal = ""
 		tok.Type = token.EOF
diff --git a/lexer/lexer_test.go b/lexer/lexer_test.go
index 209ce1e..23d3774 100644
--- a/lexer/lexer_test.go
+++ b/lexer/lexer_test.go
@@ -14,7 +14,9 @@ let add = fn(x, y) {
 x + y;
 };
 
-let result = add(five, ten);`
+let result = add(five, ten);
+!-/*5;
+5 < 10 > 5;`
 
 	tests := []struct {
 		expectedType    token.TokenType
@@ -56,6 +58,18 @@ let result = add(five, ten);`
 		{token.IDENT, "ten"},
 		{token.RPAREN, ")"},
 		{token.SEMICOLON, ";"},
+		{token.BANG, "!"},
+		{token.MINUS, "-"},
+		{token.SLASH, "/"},
+		{token.ASTERISK, "*"},
+		{token.INT, "5"},
+		{token.SEMICOLON, ";"},
+		{token.INT, "5"},
+		{token.LT, "<"},
+		{token.INT, "10"},
+		{token.GT, ">"},
+		{token.INT, "5"},
+		{token.SEMICOLON, ";"},
 		{token.EOF, ""},
 	}
 
diff --git a/token/token.go b/token/token.go
index 218eee2..36e5de1 100644
--- a/token/token.go
+++ b/token/token.go
@@ -28,8 +28,15 @@ const (
 	INT   = "INT"   // 123456
 
 	// Operators
-	ASSIGN = "="
-	PLUS   = "+"
+	ASSIGN   = "="
+	PLUS     = "+"
+	MINUS    = "-"
+	BANG     = "!"
+	ASTERISK = "*"
+	SLASH    = "/"
+
+	LT = "<"
+	GT = ">"
 
 	// Delimeters
 	COMMA     = ","

From b591493ea042db63fa64a4baa706522f267cda7a Mon Sep 17 00:00:00 2001
From: Akos <akos@Akoss-MacBook-Air.local>
Date: Sun, 6 Oct 2024 11:12:13 +0200
Subject: [PATCH 2/2] Add more keywords

---
 lexer/lexer_test.go | 25 ++++++++++++++++++++++++-
 token/token.go      | 14 ++++++++++++--
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/lexer/lexer_test.go b/lexer/lexer_test.go
index 23d3774..73783d6 100644
--- a/lexer/lexer_test.go
+++ b/lexer/lexer_test.go
@@ -16,7 +16,13 @@ x + y;
 
 let result = add(five, ten);
 !-/*5;
-5 < 10 > 5;`
+5 < 10 > 5;
+
+if (5 > 10) {
+	return false;
+} else {
+	return true;
+}`
 
 	tests := []struct {
 		expectedType    token.TokenType
@@ -70,6 +76,23 @@ let result = add(five, ten);
 		{token.GT, ">"},
 		{token.INT, "5"},
 		{token.SEMICOLON, ";"},
+		{token.IF, "if"},
+		{token.LPAREN, "("},
+		{token.INT, "5"},
+		{token.GT, ">"},
+		{token.INT, "10"},
+		{token.RPAREN, ")"},
+		{token.LBRACE, "{"},
+		{token.RETURN, "return"},
+		{token.FALSE, "false"},
+		{token.SEMICOLON, ";"},
+		{token.RBRACE, "}"},
+		{token.ELSE, "else"},
+		{token.LBRACE, "{"},
+		{token.RETURN, "return"},
+		{token.TRUE, "true"},
+		{token.SEMICOLON, ";"},
+		{token.RBRACE, "}"},
 		{token.EOF, ""},
 	}
 
diff --git a/token/token.go b/token/token.go
index 36e5de1..be34320 100644
--- a/token/token.go
+++ b/token/token.go
@@ -8,8 +8,13 @@ type Token struct {
 }
 
 var keywords = map[string]TokenType{
-	"fn":  FUNCTION,
-	"let": LET,
+	"fn":     FUNCTION,
+	"let":    LET,
+	"true":   TRUE,
+	"false":  FALSE,
+	"if":     IF,
+	"else":   ELSE,
+	"return": RETURN,
 }
 
 func LookupIdent(ident string) TokenType {
@@ -50,4 +55,9 @@ const (
 	// Keywords
 	FUNCTION = "FUNCTION"
 	LET      = "LET"
+	TRUE     = "TRUE"
+	FALSE    = "FALSE"
+	IF       = "IF"
+	ELSE     = "ELSE"
+	RETURN   = "RETURN"
 )