feat: introduce cats-effect and io

project.scala

@@ -5,23 +5,18 @@
 //> using dep com.github.j-mie6::parsley::5.0.0-M10
 //> using dep com.github.j-mie6::parsley-cats::1.5.0
 //> using dep com.lihaoyi::os-lib::0.11.4
+//> using dep org.typelevel::cats-core::2.13.0
+//> using dep org.typelevel::cats-effect::3.5.7
+//> using dep com.monovore::decline::2.5.0
+//> using dep com.monovore::decline-effect::2.5.0
 //> using dep com.github.scopt::scopt::4.1.0
 //> using test.dep org.scalatest::scalatest::3.2.19
 
-// these are all sensible defaults to catch annoying issues
+// sensible defaults for warnings and compiler checks
 //> using options -deprecation -unchecked -feature
 //> using options -Wimplausible-patterns -Wunused:all
 //> using options -Yexplicit-nulls -Wsafe-init -Xkind-projector:underscores
 
-// these will help ensure you have access to the latest parsley releases
+// repositories for pre-release versions if needed
-// even before they land on maven proper, or snapshot versions, if necessary.
+//> using repositories sonatype-s01:releases
-// just in case they cause problems, however, keep them turned off unless you
+//> using repositories sonatype-s01:snapshots
-// specifically need them.
-// using repositories sonatype-s01:releases
-// using repositories sonatype-s01:snapshots
-
-// these are flags used by Scala native: if you aren't using scala-native, then they do nothing
-// lto-thin has decent linking times, and release-fast does not too much optimisation.
-// using nativeLto thin
-// using nativeGc commix
-// using nativeMode release-fast

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(".")
@@ -36,57 +40,54 @@ val cliParser = {
 
 def frontend(
     contents: String
-)(using stdout: PrintStream): Either[microWacc.Program, Int] = {
+)(using stdout: PrintStream): IO[microWacc.Program] = {
-  parser.parse(contents) match {
+  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
+    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.nonEmpty) {
+
-        given errorContent: String = contents
+    if (errors.result.isEmpty) IO.pure(typedProg)
-        Right(
+    else {
-          errors.result
+    errors.result.foreach(printError)
-            .map { error =>
+        IO.raiseError(new RuntimeException("Compilation failed with code: " + errors.result.view.map {
-              printError(error)
-              error match {
       case _: Error.InternalError => 201
       case _                      => 200
+    }.max))
     }
   }
-            .max()
-        )
-      } else Left(typedProg)
-    case Failure(msg) =>
-      stdout.println(msg)
-      Right(100)
-  }
 }
 
 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 =
+): IO[Int] =
-  frontend(os.read(os.Path(filename))) match {
+  for {
-    case Left(typedProg) =>
+  contents <- IO(os.read(os.Path(filename)))
-      val asmFile = outFile.getOrElse(File(filename.stripSuffix(".wacc") + ".s"))
+  typedProg <- frontend(contents)
-      val asm = backend(typedProg)
+  _ <- IO {
-      writer.writeTo(asm, PrintStream(asmFile))
+        writer.writeTo(
-      0
+          backend(typedProg),
-    case Right(exitCode) => exitCode
+          PrintStream(outFile.getOrElse(File(filename.stripSuffix(".wacc") + ".s")))
+        )
   }
+} yield 0
 
-def main(args: Array[String]): Unit =
+object Main extends IOApp.Simple {
-  OParser.parse(cliParser, args, CliConfig()) match {
+  override def run: IO[Unit] =
-    case Some(config) =>
+  OParser.parse(cliParser, sys.env.getOrElse("WACC_ARGS", "").split(" "), CliConfig()).traverse_ { config =>
-      System.exit(
     compile(
       config.file.getAbsolutePath,
       outFile = Some(File(".", config.file.getName.stripSuffix(".wacc") + ".s"))
     )
-      )
+  }
-    case None =>
 }

src/test/wacc/examples.scala

@@ -7,6 +7,7 @@ import java.io.File
 import sys.process._
 import java.io.PrintStream
 import scala.io.Source
+import cats.effect.unsafe.implicits.global
 
 class ParallelExamplesSpec extends AnyFlatSpec with BeforeAndAfterAll {
   val files =
@@ -29,7 +30,7 @@ class ParallelExamplesSpec extends AnyFlatSpec with BeforeAndAfterAll {
     given stdout: PrintStream = PrintStream(File(baseFilename + ".out"))
 
     s"$filename" should "be compiled with correct result" in {
-      val result = compile(filename)
+      val result = compile(filename).unsafeRunSync()
       assert(expectedResult.contains(result))
     }