refactor: compile function split up into smaller functions

src/main/wacc/Main.scala

@@ -4,7 +4,7 @@ import scala.collection.mutable
 import cats.data.{Chain, NonEmptyList}
 import parsley.{Failure, Success}
 
-import java.nio.file.{Files, Path, Paths}
+import java.nio.file.{Files, Path}
 import cats.syntax.all._
 
 import cats.effect.IO
@@ -83,38 +83,75 @@ def backend(typedProg: microWacc.Program): Chain[asm.AsmLine] =
 
 // TODO: filename being String seems unnatural due to Path refactor
 // TODO: this function is doing too much should refactor
-def compile(filename: String, outputDir: Option[Path], log: Boolean): IO[Int] =
+// def compile(filename: String, outputDir: Option[Path], log: Boolean): IO[Int] =
+//   val logAction: String => IO[Unit] =
+//     if (log) logger.info(_)
+//     else (_ => IO.unit)
+//   for {
+//     contents <- IO.delay(
+//       os.read(os.Path(filename))
+//     ) // TODO: Is IO as a wrapper ok or do we require .delay - also, should it be .blocking?
+//     _ <- logAction(s"Compiling file: $filename")
+//     result <- frontend(contents)
+//     exitCode <- result.fold(
+//       code => logger.error(s"Compilation failed for $filename\nExit code: $code").as(code),
+//       typedProg =>
+//         val outDir = outputDir.getOrElse(Paths.get(filename).getParent)
+//         IO.delay(
+//           Files.createDirectories(outDir)
+//         ) // TODO: Is IO as a wrapper ok or do we require .delay - also, should it be .blocking?
+//         val outputFile = outDir.resolve(filename.stripSuffix(".wacc") + ".s")
+//         writer.writeTo(
+//           backend(typedProg),
+//           outputFile
+//         ) *> // TODO: I dont think we need IO here if we look at the implementation of writer
+//           logAction(s"Compilation succeeded: $filename").as(0)
+//     )
+//   } yield exitCode
+
+def compile(filePath: Path, outputDir: Option[Path], log: Boolean): IO[Int] = {
   val logAction: String => IO[Unit] =
     if (log) logger.info(_)
     else (_ => IO.unit)
+
+  def readSourceFile: IO[String] =
+    IO.blocking(os.read(os.Path(filePath)))
+
+  def ensureOutputDir(outDir: Path): IO[Path] =
+    IO.blocking {
+      Files.createDirectories(outDir)
+      outDir
+    }
+
+  // TODO: path, file , the names are confusing (when Path is the type but we are working with files)
+  def writeOutputFile(typedProg: microWacc.Program, outputPath: Path): IO[Unit] =
+    writer.writeTo(backend(typedProg), outputPath) *>
+      logger.info(s"Success: ${outputPath.toAbsolutePath}")
+
+  def processProgram(contents: String, outDir: Path): IO[Int] =
+    frontend(contents).flatMap {
+      case Left(code) =>
+        logger.error(s"Compilation failed for $filePath\nExit code: $code").as(code)
+
+      case Right(typedProg) =>
+        val outputFile = outDir.resolve(filePath.getFileName.toString.stripSuffix(".wacc") + ".s")
+        writeOutputFile(typedProg, outputFile).as(0)
+    }
+
   for {
-    contents <- IO.delay(
-      os.read(os.Path(filename))
-    ) // TODO: Is IO as a wrapper ok or do we require .delay - also, should it be .blocking?
-    _ <- logAction(s"Compiling file: $filename")
-    result <- frontend(contents)
-    exitCode <- result.fold(
-      code => logger.error(s"Compilation failed for $filename\nExit code: $code").as(code),
-      typedProg =>
-        val outDir = outputDir.getOrElse(Paths.get(filename).getParent)
-        IO.delay(
-          Files.createDirectories(outDir)
-        ) // TODO: Is IO as a wrapper ok or do we require .delay - also, should it be .blocking?
-        val outputFile = outDir.resolve(filename.stripSuffix(".wacc") + ".s")
-        writer.writeTo(
-          backend(typedProg),
-          outputFile
-        ) *> // TODO: I dont think we need IO here if we look at the implementation of writer
-          logAction(s"Compilation succeeded: $filename").as(0)
-    )
+    contents <- readSourceFile
+    _ <- logAction(s"Compiling file: ${filePath.toAbsolutePath}")
+    outDir <- ensureOutputDir(outputDir.getOrElse(filePath.getParent))
+    exitCode <- processProgram(contents, outDir)
   } yield exitCode
+}
 
 // TODO: this is sequential, thus should be what occurs when --greedy is passed in
 val compileCommand: Opts[IO[ExitCode]] =
   (filesOpt, logOpt, outputOpt).mapN { (files, log, outDir) =>
     files
       .traverse { file =>
-        compile(file.toAbsolutePath.toString, outDir, log)
+        compile(file.toAbsolutePath, outDir, log)
       }
       .map { exitCodes =>
         if (exitCodes.exists(_ != 0))

src/main/wacc/backend/writer.scala

@@ -36,7 +36,7 @@ object writer {
 
   /** Main function to write assembly to a file */
   def writeTo(asmList: Chain[AsmLine], outputPath: Path)(using logger: Logger[IO]): IO[Unit] =
-    bufferedWriter(outputPath).use { writer =>
-      writeLines(writer, asmList) *> logger.info(s"Success: ${outputPath.toAbsolutePath}")
+    bufferedWriter(outputPath).use {
+      writeLines(_, asmList)
     }
 }