Support matching on builtins and improve builtin symbols

hkmc2/jvm/src/test/scala/hkmc2/DiffTestRunner.scala

@@ -141,7 +141,7 @@ abstract class CompileTestRunner(state: DiffTestRunner.State)
 
       println(s"Compiling: $relativeName")
 
-      val preludePath = dir/"decls"/"Prelude.mls"
+      val preludePath = dir/"mlscript"/"decls"/"Prelude.mls"
 
       MLsCompiler(preludePath).compileModule(file)
 

hkmc2/jvm/src/test/scala/hkmc2/JSBackendDiffMaker.scala

@@ -5,6 +5,8 @@ import scala.collection.mutable
 import mlscript.utils.*, shorthands.*
 import utils.*
 
+import semantics.*
+import codegen.*
 import codegen.js.{JSBuilder, JSBuilderArgNumSanityChecks, JSBuilderSelSanityChecks}
 import document.*
 import codegen.Block
@@ -49,9 +51,10 @@ abstract class JSBackendDiffMaker extends MLsDiffMaker:
     if js.isSet then
       val low = ltl.givenIn:
         new codegen.Lowering with codegen.LoweringSelSanityChecks(noSanityCheck.isUnset)
-      val jsb = new JSBuilder with JSBuilderArgNumSanityChecks(noSanityCheck.isUnset) with JSBuilderSelSanityChecks(noSanityCheck.isUnset)
-      import semantics.*
-      import codegen.*
+      given Elaborator.Ctx = curCtx
+      val jsb = new JSBuilder
+        with JSBuilderArgNumSanityChecks(noSanityCheck.isUnset)
+        with JSBuilderSelSanityChecks(noSanityCheck.isUnset)
       val le = low.program(blk)
       if showLoweredTree.isSet then
         output(s"Lowered:")

hkmc2/jvm/src/test/scala/hkmc2/MLsDiffMaker.scala

@@ -50,7 +50,11 @@ abstract class MLsDiffMaker extends DiffMaker:
   val showUCS = Command("ucs"): ln =>
     ln.split(" ").iterator.map(x => "ucs:" + x.trim).toSet
 
-  given Elaborator.State = new Elaborator.State
+  given Elaborator.State = new Elaborator.State:
+    override def dbg: Bool =
+      dbgParsing.isSet
+      || dbgElab.isSet
+      || debug.isSet
 
   val etl = new TraceLogger:
     override def doTrace = dbgElab.isSet || scope.exists:
@@ -63,11 +67,12 @@ abstract class MLsDiffMaker extends DiffMaker:
       if doTrace then super.trace(pre, post)(thunk)
       else thunk
 
-  var curCtx = Elaborator.State.init.nest(N)
+  var curCtx = Elaborator.State.init
 
 
   override def run(): Unit =
     if file =/= preludeFile then importFile(preludeFile, verbose = false)
+    curCtx = curCtx.nest(N)
     super.run()
 
 

hkmc2/shared/src/main/scala/hkmc2/MLsCompiler.scala

@@ -11,6 +11,30 @@ import hkmc2.syntax.Keyword.`override`
 import semantics.Elaborator.State
 
 
+class ParserSetup(file: os.Path, dbgParsing: Bool)(using Elaborator.State, Raise):
+
+  val block = os.read(file)
+  val fph = new FastParseHelpers(block)
+  val origin = Origin(file.toString, 0, fph)
+
+  val lexer = new syntax.Lexer(origin, dbg = dbgParsing)
+  val tokens = lexer.bracketedTokens
+
+  // if showParse.isSet || dbgParsing.isSet then
+  //   output(syntax.Lexer.printTokens(tokens))
+
+  val rules = syntax.ParseRules()
+  val parser = new syntax.Parser(origin, tokens, rules, raise, dbg = dbgParsing):
+    def doPrintDbg(msg: => Str): Unit =
+      // if dbg then output(msg)
+      if dbg then println(msg)
+
+  val result = parser.parseAll(parser.block(allowNewlines = true))
+
+  val resultBlk = new syntax.Tree.Block(result)
+
+
+
 class MLsCompiler(preludeFile: os.Path):
 
 
@@ -29,40 +53,33 @@ class MLsCompiler(preludeFile: os.Path):
 
   def compileModule(file: os.Path): Unit =
 
-    val block = os.read(file)
-    val fph = new FastParseHelpers(block)
-    val origin = Origin(file.toString, 0, fph)
-
-    val lexer = new syntax.Lexer(origin, dbg = dbgParsing)
-    val tokens = lexer.bracketedTokens
+    given Elaborator.State = new Elaborator.State
 
-    // if showParse.isSet || dbgParsing.isSet then
-    //   output(syntax.Lexer.printTokens(tokens))
+    val preludeParse = ParserSetup(preludeFile, dbgParsing)
+    val mainParse = ParserSetup(file, dbgParsing)
 
-    given Elaborator.State = new Elaborator.State
-    val rules = syntax.ParseRules()
-    val p = new syntax.Parser(origin, tokens, rules, raise, dbg = dbgParsing):
-      def doPrintDbg(msg: => Str): Unit =
-        // if dbg then output(msg)
-        if dbg then println(msg)
-    val res = p.parseAll(p.block(allowNewlines = true))
-    given Elaborator.Ctx = State.init.nest(N)
     val wd = file / os.up
     val elab = Elaborator(etl, wd)
-    val resBlk = new syntax.Tree.Block(res)
-    val (blk, newCtx) = elab.importFrom(resBlk)
-    val low = ltl.givenIn:
-      codegen.Lowering()
-    val jsb = codegen.js.JSBuilder()
-    val le = low.program(blk)
-    val baseScp: codegen.js.Scope =
-      codegen.js.Scope.empty
-    val nestedScp = baseScp.nest
-    val je = nestedScp.givenIn:
-      jsb.program(le, S(file.baseName), wd)
-    val jsStr = je.stripBreaks.mkString(100)
-    val out = file / os.up / (file.baseName + ".mjs")
-    os.write.over(out, jsStr)
+
+    val initState = State.init.nest(N)
+
+    val (pblk, newCtx) = elab.importFrom(preludeParse.resultBlk)(using initState)
+
+    newCtx.nest(N).givenIn:
+
+      val (blk, newCtx) = elab.importFrom(mainParse.resultBlk)
+      val low = ltl.givenIn:
+        codegen.Lowering()
+      val jsb = codegen.js.JSBuilder()
+      val le = low.program(blk)
+      val baseScp: codegen.js.Scope =
+        codegen.js.Scope.empty
+      val nestedScp = baseScp.nest
+      val je = nestedScp.givenIn:
+        jsb.program(le, S(file.baseName), wd)
+      val jsStr = je.stripBreaks.mkString(100)
+      val out = file / os.up / (file.baseName + ".mjs")
+      os.write.over(out, jsStr)
 
 
 end MLsCompiler

hkmc2/shared/src/main/scala/hkmc2/codegen/Block.scala

@@ -82,16 +82,7 @@ case class Define(defn: Defn, rest: Block) extends Block with ProductWithTail
 sealed abstract class Defn:
   val sym: MemberSymbol[?]
 
-// final case class TermDefn(
-//     k: syntax.TermDefKind,
-//     // sym: TermSymbol,
-//     sym: BlockMemberSymbol,
-//     params: Ls[ParamList],
-//     body: Block,
-// ) extends Defn
 final case class FunDefn(
-    // k: syntax.TermDefKind,
-    // sym: TermSymbol,
     sym: BlockMemberSymbol,
     params: Ls[ParamList],
     body: Block,
@@ -101,13 +92,10 @@ final case class ValDefn(
     owner: Opt[InnerSymbol],
     k: syntax.Val,
     sym: BlockMemberSymbol,
-    // params: Ls[ParamList],
     rhs: Path,
 ) extends Defn
 
 final case class ClsLikeDefn(
-  // sym: ClassSymbol,
-  // sym: MemberSymbol[ClassLikeDef],
   sym: MemberSymbol[? <: ClassLikeDef],
   k: syntax.ClsLikeKind,
   methods: Ls[FunDefn],

hkmc2/shared/src/main/scala/hkmc2/codegen/js/JSBuilder.scala

@@ -25,7 +25,7 @@ abstract class CodeBuilder:
   type Context
 
 
-class JSBuilder(using Elaborator.State) extends CodeBuilder:
+class JSBuilder(using Elaborator.State, Elaborator.Ctx) extends CodeBuilder:
 
   val builtinOpsBase: Ls[Str] = Ls(
     "+", "-", "*", "/", "%",
@@ -238,10 +238,14 @@ class JSBuilder(using Elaborator.State) extends CodeBuilder:
       case N  => doc""
       t :: e :: returningTerm(rest)
     case Match(scrut, Case.Cls(cls, pth) -> trm :: Nil, els, rest) =>
+      val sd = result(scrut)
       val test = cls match
         // case _: semantics.ModuleSymbol => doc"=== ${result(pth)}"
-        case _ => doc"instanceof ${result(pth)}"
-      val t = doc" # if (${ result(scrut) } $test) { #{ ${
+        case Elaborator.ctx.Builtins.Str => doc"typeof $sd === 'string'"
+        case Elaborator.ctx.Builtins.Num => doc"typeof $sd === 'number'"
+        case Elaborator.ctx.Builtins.Int => doc"globalThis.Number.isInteger($sd)"
+        case _ => doc"$sd instanceof ${result(pth)}"
+      val t = doc" # if ($test) { #{ ${
           returningTerm(trm)
         } #}  # }"
       val e = els match

hkmc2/shared/src/main/scala/hkmc2/semantics/Elaborator.scala

@@ -34,11 +34,13 @@ object Elaborator:
   val reservedNames = binaryOps.toSet ++ aliasOps.keySet + "NaN" + "Infinity"
 
   case class Ctx(outer: Opt[InnerSymbol], parent: Opt[Ctx], env: Map[Str, Ctx.Elem]):
+
     def +(local: Str -> Symbol): Ctx = copy(outer, env = env + local.mapSecond(Ctx.RefElem(_)))
     def ++(locals: IterableOnce[Str -> Symbol]): Ctx =
       copy(outer, env = env ++ locals.mapValues(Ctx.RefElem(_)))
     def elem_++(locals: IterableOnce[Str -> Ctx.Elem]): Ctx =
       copy(outer, env = env ++ locals)
+
     def withMembers(members: Iterable[Str -> MemberSymbol[?]], out: Opt[Symbol] = N): Ctx =
       copy(env = env ++ members.map:
         case (nme, sym) => nme -> (
@@ -47,14 +49,29 @@ object Elaborator:
           case N => sym: Ctx.Elem
         )
       )
+
     def nest(outer: Opt[InnerSymbol]): Ctx = Ctx(outer, Some(this), Map.empty)
+
     def get(name: Str): Opt[Ctx.Elem] =
       env.get(name).orElse(parent.flatMap(_.get(name)))
     def getOuter: Opt[InnerSymbol] = outer.orElse(parent.flatMap(_.getOuter))
-    lazy val allMembers: Map[Str, Symbol] =
-      parent.fold(Map.empty)(_.allMembers) ++ env.flatMap:
-        case (n, re: Ctx.RefElem) => (n, re.sym) :: Nil
-        case _ => Nil // FIXME?
+
+    // * Invariant: We expect that the top-level context only contain hard-coded symbols like `globalThis`
+    // * and that built-in symbols like Int and Str be imported into another nested context on top of it.
+    // * It should not be possible to shadow these built-in symbols, so user code should always be compiled
+    // * in further nested contexts.
+    // * Method `getBuiltin` is used to look up built-in symbols in the context of builtin symbols.
+    def getBuiltin(nme: Str): Opt[Ctx.Elem] =
+      parent.filter(_.parent.nonEmpty).fold(env.get(nme))(_.getBuiltin(nme))
+    object Builtins:
+      private def assumeBuiltinCls(nme: Str): ClassSymbol =
+        getBuiltin(nme)
+          .getOrElse(throw new NoSuchElementException(s"builtin $nme ${env.keySet} $parent"))
+          .symbol.getOrElse(throw new NoSuchElementException(s"builtin symbol $nme"))
+          .asCls.getOrElse(throw new NoSuchElementException(s"builtin class symbol $nme"))
+      val Int = assumeBuiltinCls("Int")
+      val Num = assumeBuiltinCls("Num")
+      val Str = assumeBuiltinCls("Str")
 
   object Ctx:
     abstract class Elem:
@@ -76,8 +93,11 @@ object Elaborator:
       def symbol = symOpt
     given Conversion[Symbol, Elem] = RefElem(_)
     val empty: Ctx = Ctx(N, N, Map.empty)
+
   type Ctxl[A] = Ctx ?=> A
-  def ctx: Ctxl[Ctx] = summon
+
+  transparent inline def ctx(using Ctx): Ctx = summon
+
   class State:
     given State = this
     val suid = new Uid.Symbol.State
@@ -86,9 +106,16 @@ object Elaborator:
     def init(using State): Ctx = Ctx.empty.copy(env = Map(
       "globalThis" -> globalThisSymbol,
     ))
+    def dbg: Bool = false
+    def dbgUid(uid: Uid[Symbol]): Str = if dbg then s"‹$uid›" else ""
   transparent inline def State(using state: State): State = state
+
+end Elaborator
+
+
 import Elaborator.*
 
+
 class Elaborator(val tl: TraceLogger, val wd: os.Path)
 (using val raise: Raise, val state: State)
 extends Importer:

hkmc2/shared/src/main/scala/hkmc2/semantics/Symbol.scala

@@ -61,8 +61,7 @@ class FlowSymbol(label: Str)(using State) extends Symbol:
   val outFlows2: mutable.Buffer[Consumer] = mutable.Buffer.empty
   val inFlows: mutable.Buffer[ConcreteProd] = mutable.Buffer.empty
   override def toString: Str =
-    label
-    // s"$label@$uid"
+    label + State.dbgUid(uid)
 
 
 sealed trait LocalSymbol extends Symbol
@@ -86,7 +85,7 @@ class BuiltinSymbol
     (val nme: Str, val binary: Bool, val unary: Bool, val nullary: Bool)(using State)
     extends Symbol:
   def toLoc: Option[Loc] = N
-  override def toString: Str = s"builtin:$nme"
+  override def toString: Str = s"builtin:$nme${State.dbgUid(uid)}"
 
 
 /** This is the outside-facing symbol associated to a possibly-overloaded
@@ -110,7 +109,8 @@ class BlockMemberSymbol(val nme: Str, val trees: Ls[Tree])(using State)
   lazy val hasLiftedClass: Bool =
     modTree.isDefined || trmTree.isDefined || clsTree.exists(_.paramLists.nonEmpty)
 
-  override def toString: Str = s"member:$nme"
+  override def toString: Str =
+    s"member:$nme${State.dbgUid(uid)}"
 
 end BlockMemberSymbol
 
@@ -157,25 +157,25 @@ class ClassSymbol(val tree: Tree.TypeDef, val id: Tree.Ident)(using State)
     extends MemberSymbol[ClassDef] with CtorSymbol with InnerSymbol:
   def nme = id.name
   def toLoc: Option[Loc] = id.toLoc // TODO track source tree of classe here
-  override def toString: Str = s"class:$nme"
+  override def toString: Str = s"class:$nme${State.dbgUid(uid)}"
   /** Compute the arity. */
   def arity: Int = tree.paramLists.headOption.fold(0)(_.fields.length)
 
 class ModuleSymbol(val tree: Tree.TypeDef, val id: Tree.Ident)(using State)
     extends MemberSymbol[ModuleDef] with CtorSymbol with InnerSymbol:
   def nme = id.name
   def toLoc: Option[Loc] = id.toLoc // TODO track source tree of module here
-  override def toString: Str = s"module:${id.name}"
+  override def toString: Str = s"module:${id.name}${State.dbgUid(uid)}"
 
 class TypeAliasSymbol(val id: Tree.Ident)(using State) extends MemberSymbol[TypeDef]:
   def nme = id.name
   def toLoc: Option[Loc] = id.toLoc // TODO track source tree of type alias here
-  override def toString: Str = s"module:${id.name}"
+  override def toString: Str = s"module:${id.name}${State.dbgUid(uid)}"
 
 class TopLevelSymbol(blockNme: Str)(using State)
     extends MemberSymbol[ModuleDef] with InnerSymbol:
   def nme = blockNme
   def toLoc: Option[Loc] = N
-  override def toString: Str = s"globalThis:$blockNme"
+  override def toString: Str = s"globalThis:$blockNme${State.dbgUid(uid)}"
 
 

hkmc2/shared/src/main/scala/hkmc2/syntax/Tree.scala

@@ -131,7 +131,7 @@ enum Tree extends AutoLocated:
     case Jux(lhs, rhs) => "juxtaposition"
     case SynthSel(prefix, name) => "synthetic selection"
     case Sel(prefix, name) => "selection"
-    case InfixApp(lhs, kw, rhs) => "infix application"
+    case InfixApp(lhs, kw, rhs) => "infix operation"
     case New(body) => "new"
     case IfLike(Keyword.`if`, split) => "if expression"
     case IfLike(Keyword.`while`, split) => "while expression"

hkmc2/shared/src/test/mlscript-compile/Example.mjs

@@ -8,6 +8,21 @@ const Example$class = class Example {
   } 
   inc(x) {
     return x + 1;
+  } 
+  test(x1) {
+    if (globalThis.Number.isInteger(x1)) {
+      return "int";
+    } else {
+      if (typeof x1 === 'number') {
+        return "num";
+      } else {
+        if (typeof x1 === 'string') {
+          return "str";
+        } else {
+          return "other";
+        }
+      }
+    }
   }
   toString() { return "Example"; }
 }; const Example = new Example$class;

hkmc2/shared/src/test/mlscript-compile/Example.mls

@@ -10,4 +10,10 @@ fun (/) funnySlash(f, arg) = f(arg)
 
 fun inc(x) = x + 1
 
+fun test(x) = if x is
+  Int then "int"
+  Num then "num"
+  Str then "str"
+  else "other"
+
 

hkmc2/shared/src/test/mlscript-compile/Predef.mls

@@ -1,7 +1,4 @@
 
-declare val String
-declare val console
-
 module Predef with ...
 
 fun id(x) = x