token and begin lexer

cmd/main.go

@@ -0,0 +1 @@
+package main

lexer/lexer.go

@@ -0,0 +1,54 @@
+package lexer
+
+import "robaertschi.xyz/robaertschi/thorgot/token"
+
+type Lexer struct {
+	input   string
+	ch      byte
+	pos     int
+	readPos int
+
+	// Loc
+	col  int
+	line int
+}
+
+func New(input string) Lexer {
+	lexer := Lexer{input: input}
+
+	lexer.readChar()
+
+	return lexer
+}
+
+func (l *Lexer) readChar() {
+	if l.readPos >= len(l.input) {
+		l.ch = 0
+	} else {
+		l.ch = l.input[l.readPos]
+	}
+
+	if l.ch == '\n' {
+		l.col = 0
+		l.line += 1
+	}
+
+	l.pos = l.readPos
+	l.readPos += 1
+	l.col += 1
+}
+
+func (l *Lexer) makeToken(t token.TokenType, literal string) token.Token {
+	return token.Token{Token: t, Literal: literal, Loc: token.Loc{Line: l.line, Col: l.col}}
+}
+
+func (l *Lexer) NextToken() token.Token {
+	var token token.Token
+
+	switch l.ch {
+	case 0:
+
+	}
+
+	return token
+}

token/token.go

@@ -0,0 +1,46 @@
+package token
+
+type TokenType string
+
+type Loc struct {
+	Line int
+	Col  int
+}
+
+type Token struct {
+	Token   TokenType
+	Literal string
+	Loc     Loc
+}
+
+const (
+	Illegal TokenType = "Illegal"
+	Eof               = "Eof"
+
+	EndLine = "EndLine"
+
+	Semicolon = "Semicolon" // ;
+	Colon     = "Colon"     // :
+	Equal     = "Equal"     // =
+	LBrace    = "LBrace"    // {
+	RBrace    = "RBrace"    // }
+	LParen    = "LParen"    // (
+	RParen    = "RParen"    // )
+
+	Identifier = "Identifier"
+
+	// Keywords
+	Fn = "Fn" // fn
+)
+
+var stringToToken = map[string]TokenType{
+	"fn": Fn,
+}
+
+func LookupKeyword(literal string) TokenType {
+	if token, ok := stringToToken[literal]; ok {
+		return token
+	}
+
+	return Identifier
+}