write to things

scratchpad/src/main/scala/com/htmlism/scratchpad/Enum.scala

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+package com.htmlism.scratchpad
+
+trait Enum[A] {}

scratchpad/src/main/scala/com/htmlism/scratchpad/Loadable.scala

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+package com.htmlism.scratchpad
+
+trait Loadable[A]:
+  def show(x: A): String
+
+object Loadable:
+  given intLoadable: Loadable[Int] with
+    def show(x: Int): String =
+      x.toString

scratchpad/src/main/scala/com/htmlism/scratchpad/Register.scala

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+package com.htmlism.scratchpad
+
+sealed trait Register[A]:
+  def self: String
+
+object Register:
+  given registerA: Register[A] with
+    def self: String = "A"
+
+  given registerX: Register[X] with
+    def self: String = "X"
+
+  given registerY: Register[Y] with
+    def self: String = "Y"
+
+  class A
+  class X
+  class Y

scratchpad/src/main/scala/com/htmlism/scratchpad/addresses.scala

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+package com.htmlism.scratchpad
+
+object Address:
+  def zero(n: Int): ZeroPageAddress =
+    ZeroPageAddress(n % 256)
+
+  def absolute(n: Int): GlobalAddress =
+    GlobalAddress(n % (256 * 256))
+
+case class ZeroPageAddress(n: Int)
+
+case class GlobalAddress(n: Int)
+
+sealed trait ReadAddress:
+  def addr: ZeroPageAddress
+
+sealed trait WriteAddress:
+  def addr: ZeroPageAddress
+
+case class Volatile(addr: ZeroPageAddress) extends ReadAddress
+
+case class ReadWriteAddress(addr: ZeroPageAddress) extends ReadAddress with WriteAddress
+
+case class WriteOnlyAddress(addr: ZeroPageAddress) extends WriteAddress

scratchpad/src/main/scala/com/htmlism/scratchpad/syntax/package.scala

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+package com.htmlism.scratchpad
+
+package object syntax:
+  implicit class WriteRegisterOps(reg: WriteAddress):
+    def write[A: Loadable](x: A): PartiallyAppliedWrite[A] =
+      new PartiallyAppliedWrite(reg, x)
+
+  class PartiallyAppliedWrite[A: Loadable](reg: WriteAddress, x: A):
+    def apply[B: Register]: String =
+      reg.addr.n.toString + summon[Loadable[A]].show(x) + summon[Register[B]].self

scratchpad/src/test/scala/com/htmlism/scratchpad/FeatureSpec.scala

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+package com.htmlism.scratchpad
+
+import org.scalatest.funsuite.AnyFunSuite
+import org.scalatest.matchers.should._
+
+import com.htmlism.scratchpad.syntax._
+
+class FeatureSpec extends AnyFunSuite with Matchers:
+  test("zero page address as write only supports writing") {
+    WriteOnlyAddress(Address.zero(0x01))
+      .write(2)[Register.A] shouldBe "12A"
+  }
+
+  test("zero page address as read/write supports writing") {
+    ReadWriteAddress(Address.zero(0x01))
+      .write(2)[Register.A] shouldBe "12A"
+  }
+
+  test("writing to an address can use A, X, and Y registers for bouncing ") {
+    ReadWriteAddress(Address.zero(0x01))
+      .write(2)[Register.A] shouldBe "12A"
+
+    ReadWriteAddress(Address.zero(0x01))
+      .write(2)[Register.X] shouldBe "12X"
+
+    ReadWriteAddress(Address.zero(0x01))
+      .write(2)[Register.Y] shouldBe "12Y"
+  }