feat: introduce cats-effect and io

src/main/wacc/Main.scala

@@ -6,8 +6,12 @@ import parsley.{Failure, Success}
 import scopt.OParser
 import java.io.File
 import java.io.PrintStream
+import cats.implicits._
+import cats.effect.unsafe.implicits.global
 
 import assemblyIR as asm
+import cats.effect.IO
+import cats.effect.IOApp
 
 case class CliConfig(
     file: File = new File(".")
@@ -36,30 +40,26 @@ val cliParser = {
 
 def frontend(
     contents: String
-)(using stdout: PrintStream): Either[microWacc.Program, Int] = {
-  parser.parse(contents) match {
+)(using stdout: PrintStream): IO[microWacc.Program] = {
+  IO(parser.parse(contents)).flatMap {
+    case Failure(msg) => IO.raiseError(new RuntimeException(msg))
     case Success(prog) =>
-      given errors: mutable.Builder[Error, List[Error]] = List.newBuilder
-      val (names, funcs) = renamer.rename(prog)
-      given ctx: typeChecker.TypeCheckerCtx = typeChecker.TypeCheckerCtx(names, funcs, errors)
-      val typedProg = typeChecker.check(prog)
-      if (errors.result.nonEmpty) {
-        given errorContent: String = contents
-        Right(
-          errors.result
-            .map { error =>
-              printError(error)
-              error match {
-                case _: Error.InternalError => 201
-                case _                      => 200
-              }
-            }
-            .max()
-        )
-      } else Left(typedProg)
-    case Failure(msg) =>
-      stdout.println(msg)
-      Right(100)
+    given errors: mutable.Builder[Error, List[Error]] = List.newBuilder
+    given errorContent: String = contents
+
+    val (names, funcs) = renamer.rename(prog)
+    given ctx: typeChecker.TypeCheckerCtx = typeChecker.TypeCheckerCtx(names, funcs, errors)
+
+    val typedProg = typeChecker.check(prog)
+
+    if (errors.result.isEmpty) IO.pure(typedProg)
+    else {
+    errors.result.foreach(printError)
+        IO.raiseError(new RuntimeException("Compilation failed with code: " + errors.result.view.map {
+      case _: Error.InternalError => 201
+      case _                      => 200
+    }.max))
+    }
   }
 }
 
@@ -67,26 +67,27 @@ val s = "enter an integer to echo"
 def backend(typedProg: microWacc.Program): Chain[asm.AsmLine] =
   asmGenerator.generateAsm(typedProg)
 
+
 def compile(filename: String, outFile: Option[File] = None)(using
     stdout: PrintStream = Console.out
-): Int =
-  frontend(os.read(os.Path(filename))) match {
-    case Left(typedProg) =>
-      val asmFile = outFile.getOrElse(File(filename.stripSuffix(".wacc") + ".s"))
-      val asm = backend(typedProg)
-      writer.writeTo(asm, PrintStream(asmFile))
-      0
-    case Right(exitCode) => exitCode
-  }
-
-def main(args: Array[String]): Unit =
-  OParser.parse(cliParser, args, CliConfig()) match {
-    case Some(config) =>
-      System.exit(
-        compile(
-          config.file.getAbsolutePath,
-          outFile = Some(File(".", config.file.getName.stripSuffix(".wacc") + ".s"))
+): IO[Int] =
+  for {
+  contents <- IO(os.read(os.Path(filename)))
+  typedProg <- frontend(contents)
+  _ <- IO {
+        writer.writeTo(
+          backend(typedProg),
+          PrintStream(outFile.getOrElse(File(filename.stripSuffix(".wacc") + ".s")))
         )
-      )
-    case None =>
   }
+} yield 0
+
+object Main extends IOApp.Simple {
+  override def run: IO[Unit] =
+  OParser.parse(cliParser, sys.env.getOrElse("WACC_ARGS", "").split(" "), CliConfig()).traverse_ { config =>
+    compile(
+      config.file.getAbsolutePath,
+      outFile = Some(File(".", config.file.getName.stripSuffix(".wacc") + ".s"))
+    )
+  }
+}