Find keywords

Use runes/chars for characters

scanner.go

@@ -31,76 +31,76 @@ func (s *Scanner) ScanTokens() []Token {
 func (s *Scanner) scanToken() {
 	c := s.advance()
 	switch c {
-	case "(":
+	case '(':
 		s.addToken(LeftBrace)
 		break
-	case ")":
+	case ')':
 		s.addToken(RightBrace)
 		break
-	case "{":
+	case '{':
 		s.addToken(LeftBrace)
 		break
-	case "}":
+	case '}':
 		s.addToken(RightBrace)
 		break
-	case ",":
+	case ',':
 		s.addToken(Comma)
 		break
-	case ".":
+	case '.':
 		s.addToken(Dot)
 		break
-	case "-":
+	case '-':
 		s.addToken(Minus)
 		break
-	case "+":
+	case '+':
 		s.addToken(Plus)
 		break
-	case ";":
+	case ';':
 		s.addToken(Semicolon)
 		break
-	case "*":
+	case '*':
 		s.addToken(Star)
 		break
-	case "!":
-		if s.match("=") {
+	case '!':
+		if s.match('=') {
 			s.addToken(BangEqual)
 		} else {
 			s.addToken(Bang)
 		}
 		break
-	case "=":
-		if s.match("=") {
+	case '=':
+		if s.match('=') {
 			s.addToken(EqualEqual)
 		} else {
 			s.addToken(Equal)
 		}
 		break
-	case "<":
-		if s.match("=") {
+	case '<':
+		if s.match('=') {
 			s.addToken(LessEqual)
 		} else {
 			s.addToken(Less)
 		}
 		break
-	case ">":
-		if s.match("=") {
+	case '>':
+		if s.match('=') {
 			s.addToken(GreaterEqual)
 		} else {
 			s.addToken(Greater)
 		}
 		break
-	case "/":
-		if s.match("/") {
-			for s.peek() != "\n" && !s.isAtEnd() {
+	case '/':
+		if s.match('/') {
+			for s.peek() != '\n' && !s.isAtEnd() {
 				s.advance()
 			}
 		} else {
 			s.addToken(Slash)
 		}
 		break
-	case "\"":
-		for s.peek() != "\"" && !s.isAtEnd() {
-			if s.peek() == "\n" {
+	case '"':
+		for s.peek() != '"' && !s.isAtEnd() {
+			if s.peek() == '\n' {
 				s.line += 1
 			}
 			s.advance()
@@ -115,12 +115,11 @@ func (s *Scanner) scanToken() {
 		s.addTokenWithLiteral(String, s.source[s.start+1:s.current-1]) // +- to remove ""
 
 		break
-	case " ":
-	case "\t":
-	case "\r":
-		// ignore whitespace
+	case ' ':
+	case '\t':
+	case '\r':
 		break
-	case "\n":
+	case '\n':
 		s.line += 1
 		break
 	default:
@@ -128,10 +127,8 @@ func (s *Scanner) scanToken() {
 			for s.isDigit(s.peek()) {
 				s.advance()
 			}
-
-			if s.peek() == "." && s.isDigit(s.peekAfter()) {
+			if s.peek() == '.' && s.isDigit(s.peekAfter()) {
 				s.advance() // eated .
-
 				for s.isDigit(s.peek()) {
 					s.advance()
 				}
@@ -143,6 +140,19 @@ func (s *Scanner) scanToken() {
 			}
 
 			s.addTokenWithLiteral(Number, fmt.Sprintf("%f", number)) // convert back to string, lol
+		} else if s.isAlpha(c) {
+			for s.isAlpha(s.peek()) {
+				s.advance()
+			}
+
+			keyword := s.source[s.start:s.current]
+
+			val, ok := Tokens[keyword]
+			if !ok {
+				val = Identifier
+			}
+
+			s.addToken(val)
 		} else {
 			fuck(s.line, "Unexpected Character")
 		}
@@ -150,45 +160,51 @@ func (s *Scanner) scanToken() {
 	}
 }
 
-func (s *Scanner) advance() string {
-	c := string(s.source[s.current])
+func (s *Scanner) advance() rune {
+	c := rune(s.source[s.current])
 	s.current += 1
 	return c
 }
 
-func (s *Scanner) peek() string {
+func (s *Scanner) peek() rune {
 	if s.isAtEnd() {
-		return ""
+		return '0'
 	}
-	return string(s.source[s.current])
+	return rune(s.source[s.current])
 }
 
-func (s *Scanner) peekAfter() string {
+func (s *Scanner) peekAfter() rune {
 	if s.current+1 >= len(s.source) {
-		return ""
+		return '0'
 	}
-	return string(s.source[s.current+1])
+	return rune(s.source[s.current+1])
 }
 
-func (s *Scanner) match(expected string) bool {
+func (s *Scanner) match(c rune) bool {
 	if s.isAtEnd() {
 		return false
 	}
-	if string(s.source[s.current]) != expected {
+	if rune(s.source[s.current]) != c {
 		return false
 	}
 	s.current += 1
 	return true
 }
 
-func (s *Scanner) isDigit(val string) bool {
-	// Lazy way of doing thia, Atoi could work, but unsure if it has any funkiness to it.....
-	for _, number := range "0123456789" {
-		if val == string(number) {
-			return true
+func (s *Scanner) isDigit(c rune) bool {
+	return c >= '0' && c <= '9'
 }
+
+func (s *Scanner) isAlpha(c rune) bool {
+	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_'
 }
-	return false
+
+func (s *Scanner) isAlphaNumeric(c rune) bool {
+	return s.isAlpha(c) || s.isDigit(c)
+}
+
+func (s *Scanner) isAtEnd() bool {
+	return s.current >= len(s.source)
 }
 
 func (s *Scanner) addToken(token int) {
@@ -198,8 +214,6 @@ func (s *Scanner) addToken(token int) {
 		Literal: "",
 		Line:    s.line,
 	})
-	//fmt.Printf("[%d %d %d] ", s.line, s.current, s.start)
-	//fmt.Println(s.tokens[len(s.tokens)-1])
 }
 
 func (s *Scanner) addTokenWithLiteral(token int, value string) {
@@ -211,10 +225,6 @@ func (s *Scanner) addTokenWithLiteral(token int, value string) {
 	})
 }
 
-func (s *Scanner) isAtEnd() bool {
-	return s.current >= len(s.source)
-}
-
 func NewScanner(source string) *Scanner {
 	return &Scanner{
 		source:  source,

scripts/function.lox

@@ -0,0 +1,12 @@
+fun main() {
+    example("world")
+}
+
+fun example(name) {
+    print "Hello, "
+    print name
+    print "!\n"
+}
+
+// Start program
+main()

tokens.go

@@ -41,7 +41,7 @@ const (
 	Fun
 	For
 	If
-	Nah
+	Null
 	Or
 	Print
 	Return
@@ -54,6 +54,25 @@ const (
 	EOF
 )
 
+var Tokens = map[string]int{
+	"and":    And,
+	"class":  Class,
+	"else":   Else,
+	"false":  False,
+	"fun":    Fun,
+	"for":    For,
+	"if":     If,
+	"null":   Null,
+	"or":     Or,
+	"print":  Print,
+	"return": Return,
+	"super":  Super,
+	"this":   This,
+	"true":   True,
+	"var":    Var,
+	"while":  While,
+}
+
 type Token struct {
 	Type    int
 	Lexeme  string