Expanding on definitions, starting the tokenizer implementation.

modules/parser/src/main/scala/ava/parser/Keyword.scala

@@ -33,4 +33,38 @@ object Keyword:
   case object True      extends Keyword("true")
   case object Type      extends Keyword("type")
 
+  val All: List[Keyword] = List(
+    Alias,
+    Case,
+    Class,
+    Const,
+    Defn,
+    Do,
+    Else,
+    End,
+    Enum,
+    Export,
+    False,
+    Fn,
+    Given,
+    If,
+    Import,
+    Infix,
+    Lambda,
+    Let,
+    Match,
+    Mut,
+    Namespace,
+    Object,
+    Private,
+    Record,
+    Return,
+    Then,
+    True,
+    Type
+  )
+
+  def isKeyword(candidate: String): Boolean =
+    All.contains(candidate)
+
 end Keyword

modules/parser/src/main/scala/ava/parser/Name.scala

@@ -0,0 +1,15 @@
+package ava.parser
+
+sealed trait Name:
+  def value: String
+
+object Name:
+  case class UserDef(value: String) extends Name
+
+  case object AnonValue extends Name:
+    val value: String = "_"
+
+  case object AnonType extends Name:
+    val value: String = "*"
+
+end Name

modules/parser/src/main/scala/ava/parser/Operator.scala

@@ -0,0 +1,33 @@
+package ava.parser
+
+sealed abstract class Operator(val value: String)
+
+object Operator:
+
+  case object Hole        extends Operator("???")
+  case object ImportSplat extends Operator("*")
+  case object Member      extends Operator(".")
+  case object Union       extends Operator("|")
+  case object ListPrepend extends Operator(":-")
+  case object BindType    extends Operator(":")
+  case object BindValue   extends Operator(":=")
+  case object FnReturn    extends Operator("->")
+  case object BindDo      extends Operator("<-")
+  case object ClassMember extends Operator("::")
+  case object Case        extends Operator("=>")
+
+  val All: List[Operator] = List(
+    Hole,
+    ImportSplat,
+    Member,
+    Union,
+    ListPrepend,
+    BindType,
+    BindValue,
+    FnReturn,
+    BindDo,
+    ClassMember,
+    Case
+  )
+
+end Operator

modules/parser/src/main/scala/ava/parser/Token.scala

@@ -1,6 +1,52 @@
 package ava.parser
 
-case class Token(
-  value: String,
-  tokenType: TokenType
-)
+sealed trait Token
+
+object Token:
+  /** Most tokens are generic tokens. They represent some arbitrary grouping of
+    * characters that will be refined later.
+    *
+    * @param value
+    *   The token value.
+    */
+  case class Generic(value: String) extends Token
+
+  /** Comments are detected at time of tokenization, and are arbitrary strings.
+    *
+    * @param value
+    *   The comment value.
+    */
+  case class Comment(value: String) extends Token
+
+  /** The '(' character.
+    */
+  case object OpenParen extends Token
+
+  /** The ')' character.
+    */
+  case object CloseParen extends Token
+
+  /** The '.' character.
+    */
+  case object Dot extends Token
+
+  /** The ',' character.
+    */
+  case object Comma extends Token
+
+  /** The '"' character.
+    */
+  case object DoubleQuote extends Token
+
+  /** The ''' character.
+    */
+  case object SingleQuote extends Token
+
+  /** The ':' character.
+    */
+  case object Colon extends Token
+
+  /** The '#' character.
+    */
+  case object Tuple extends Token
+end Token

modules/parser/src/main/scala/ava/parser/TokenType.scala

@@ -1,18 +0,0 @@
-package ava.parser
-
-sealed trait TokenType
-
-object TokenType:
-
-  case object Keyword          extends TokenType
-  case object ReservedOperator extends TokenType
-  case object Name             extends TokenType
-  case object OpenParen        extends TokenType
-  case object CloseParen       extends TokenType
-  case object Dot              extends TokenType
-  case object Comma            extends TokenType
-  case object DoubleQuote      extends TokenType
-  case object Hole             extends TokenType
-  case object Literal          extends TokenType
-
-end TokenType

modules/parser/src/main/scala/ava/parser/Tokenizer.scala

@@ -1,6 +1,26 @@
 package ava.parser
 
 class Tokenizer(private val reader: CharacterReader):
-  def next(): Option[String] = None
+  import Tokenizer.*
+
+  private var state: State = State.Initial
+
+  def next(): Option[Token] = None
 
   def close(): Unit = reader.close()
+
+object Tokenizer:
+
+  sealed trait State
+
+  object State:
+
+    case object Initial          extends State
+    case object PotentialComment extends State
+    case object InComment        extends State
+    case object InQuote          extends State
+    case object InGeneric        extends State
+
+  end State
+
+end Tokenizer