init + lexer

tokentype.go

@@ -0,0 +1,71 @@
+package main
+
+import "fmt"
+
+//go:generate stringer -type tokenType -linecomment -trimprefix tokenType
+type tokenType int
+
+const (
+	// single char tokens
+
+	tokenTypeLeftParen tokenType = iota
+	tokenTypeRightParen
+	tokenTypeLeftBrace
+	tokenTypeRightBrace
+	tokenTypeComma
+	tokenTypeDot
+	tokenTypeMinus
+	tokenTypePlus
+	tokenTypeSemicolon
+	tokenTypeSlash
+	tokenTypeStar
+
+	// 1-2 char token
+
+	tokenTypeBang
+	tokenTypeBangEq
+	tokenTypeEqual
+	tokenTypeEqualEqual
+	tokenTypeGreater
+	tokenTypeGreaterEq
+	tokenTypeLess
+	tokenTypeLessEq
+
+	// literals
+
+	tokenTypeIdentifier
+	tokenTypeString
+	tokenTypeNumber
+
+	// keywords
+
+	tokenTypeAnd
+	tokenTypeClass
+	tokenTypeElse
+	tokenTypeFalse
+	tokenTypeFun
+	tokenTypeFor
+	tokenTypeIf
+	tokenTypeNil
+	tokenTypeOr
+	tokenTypePrint
+	tokenTypeReturn
+	tokenTypeSuper
+	tokenTypeThis
+	tokenTypeTrue
+	tokenTypeVar
+	tokenTypeWhile
+
+	tokenTypeEOF
+)
+
+type token struct {
+	Type    tokenType
+	Lexeme  string
+	Literal any
+	Line    int
+}
+
+func (t token) String() string {
+	return fmt.Sprintf("%s %s %+v", t.Type, t.Lexeme, t.Literal)
+}