Add code generation for bbml (#245)

Author: NeilKleistGao

hkmc2/jvm/src/test/scala/hkmc2/BbmlDiffMaker.scala

@@ -9,16 +9,33 @@ import hkmc2.bbml.*
 abstract class BbmlDiffMaker extends JSBackendDiffMaker:
 
   val bbPreludeFile = file / os.up / os.RelPath("bbPrelude.mls")
+  val bbPredefFile = file / os.up / os.up / os.up /"mlscript-compile"/"bbml"/"Predef.mls"
 
   val bbmlOpt = new NullaryCommand("bbml"):
     override def onSet(): Unit =
       super.onSet()
       if isGlobal then typeCheck.disable.isGlobal = true
       typeCheck.disable.setCurrentValue(())
       if file =/= bbPreludeFile then
+        curCtx = Elaborator.State.init
         importFile(bbPreludeFile, verbose = false)
+        curCtx = curCtx.nest(N)
 
 
+  override def init(): Unit =
+    if bbmlOpt.isSet then
+      import syntax.*
+      import Tree.*
+      import Keyword.*
+      given raise: Raise = d =>
+        output(s"Error: $d")
+        ()
+      processTrees(
+        Modified(`import`, N, StrLit(bbPredefFile.toString))
+        :: Open(Ident("Predef"))
+        :: Nil)
+    super.init()
+
   lazy val bbCtx =
     given Elaborator.Ctx = curCtx
     bbml.BbCtx.init(_ => die)

hkmc2/shared/src/main/scala/hkmc2/bbml/bbML.scala

@@ -45,6 +45,7 @@ object BbCtx:
   def numTy(using ctx: BbCtx): Type = ClassLikeType(ctx.getCls("Num").get, Nil)
   def strTy(using ctx: BbCtx): Type = ClassLikeType(ctx.getCls("Str").get, Nil)
   def boolTy(using ctx: BbCtx): Type = ClassLikeType(ctx.getCls("Bool").get, Nil)
+  def errTy(using ctx: BbCtx): Type = ClassLikeType(ctx.getCls("Error").get, Nil)
   private def codeBaseTy(ct: TypeArg, cr: TypeArg, isVar: TypeArg)(using ctx: BbCtx): Type =
     ClassLikeType(ctx.getCls("CodeBase").get, ct :: cr :: isVar :: Nil)
   def codeTy(ct: Type, cr: Type)(using ctx: BbCtx): Type =
@@ -57,6 +58,8 @@ object BbCtx:
     ClassLikeType(ctx.getCls("Ref").get, Wildcard(ct, ct) :: Wildcard.out(sk) :: Nil)
   def init(raise: Raise)(using Elaborator.State, Elaborator.Ctx): BbCtx =
     new BbCtx(raise, summon, None, 1, HashMap.empty)
+
+  val builtinOps = Set("+", "-", "*", "/", "<", ">", "<=", ">=", "==", "!=", "&&", "||")
 end BbCtx
 
 
@@ -183,6 +186,10 @@ class BBTyper(using elState: Elaborator.State, tl: TL):
       case _: UnitLit => Top
       case _: BoolLit => BbCtx.boolTy), Bot, Bot)
     case Ref(sym: Symbol) if sym.nme === "error" => (Bot, Bot, Bot)
+    case Ref(sym: Symbol) if BbCtx.builtinOps(sym.nme) => ctx.get(sym) match
+      case S(ty) => (tryMkMono(ty, code), Bot, Bot)
+      case N =>
+        (error(msg"Cannot quote operator ${sym.nme}" -> code.toLoc :: Nil), Bot, Bot)
     case Lam(PlainParamList(params), body) =>
       val nestCtx = ctx.nextLevel
       given BbCtx = nestCtx
@@ -257,7 +264,7 @@ class BBTyper(using elState: Elaborator.State, tl: TL):
     split match
     case Split.Cons(Branch(scrutinee, Pattern.ClassLike(sym, _, _, _), cons), alts) =>
       // * Pattern matching for classes
-      val (clsTy, tv, emptyTy) = ctx.getCls(sym.nme).flatMap(_.defn) match
+      val (clsTy, tv, emptyTy) = sym.asCls.flatMap(_.defn) match
         case S(cls) =>
           (ClassLikeType(sym, cls.tparams.map(_ => freshWildcard(N))), (freshVar(N)), ClassLikeType(sym, cls.tparams.map(_ => Wildcard.empty)))
         case _ =>
@@ -304,7 +311,7 @@ class BBTyper(using elState: Elaborator.State, tl: TL):
     case Split.Else(alts) => sign match
       case S(sign) => ascribe(alts, sign)
       case _ => typeCheck(alts)
-    case Split.End => ???
+    case Split.End => (Bot, Bot)
 
   // * Note: currently, the returned type is not used or useful, but it could be in the future
   private def ascribe(lhs: Term, rhs: GeneralType)(using ctx: BbCtx): (GeneralType, Type) =
@@ -424,6 +431,10 @@ class BBTyper(using elState: Elaborator.State, tl: TL):
             goStats(stats)
           case (clsDef: ClassDef) :: stats =>
             goStats(stats)
+          case (modDef: ModuleDef) :: stats =>
+            goStats(stats)
+          case Import(sym, pth) :: stats =>
+            goStats(stats) // TODO:
         goStats(stats)
         val (ty, eff) = typeCheck(res)
         (ty, effBuff.foldLeft(eff)((res, e) => res | e))
@@ -464,7 +475,9 @@ class BBTyper(using elState: Elaborator.State, tl: TL):
               case _ => (error(msg"${field.name} is not a valid member in class ${clsSym.nme}" -> t.toLoc :: Nil), Bot)
           case N => 
             (error(msg"Not a valid class: ${cls.describe}" -> cls.toLoc :: Nil), Bot)
-      case Term.App(lhs, Term.Tup(rhs)) =>
+      case Term.App(lhs: Term.SynthSel, Term.Tup(Nil)) if lhs.sym.exists(_.isGetter) =>
+        typeCheck(lhs) // * Getter access will be elaborated to applications. But they cannot be typed as normal applications.
+      case t @ Term.App(lhs, Term.Tup(rhs)) =>
         val (funTy, lhsEff) = typeCheck(lhs)
         app((funTy, lhsEff), rhs, t)
       case Term.New(cls, args) =>
@@ -517,7 +530,7 @@ class BBTyper(using elState: Elaborator.State, tl: TL):
         val sk = freshVar(N)
         constrain(tryMkMono(regTy, reg), BbCtx.regionTy(sk))
         (BbCtx.refTy(tryMkMono(valTy, value), sk), sk | (regEff | valEff))
-      case Term.Assgn(lhs, rhs) =>
+      case Term.SetRef(lhs, rhs) =>
         val (lhsTy, lhsEff) = typeCheck(lhs)
         val (rhsTy, rhsEff) = typeCheck(rhs)
         val sk = freshVar(N)
@@ -536,6 +549,10 @@ class BBTyper(using elState: Elaborator.State, tl: TL):
         (BbCtx.codeTy(ty, ctxTy), eff)
       case _: Term.Unquoted =>
         (error(msg"Unquote should nest in quasiquote" -> t.toLoc :: Nil), Bot)
+      case Throw(e) =>
+        val (ty, eff) = typeCheck(e)
+        constrain(tryMkMono(ty, e), BbCtx.errTy)
+        (Bot, eff)
       case Term.Error =>
         (Bot, Bot) // TODO: error type?
       case _ =>

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

@@ -305,6 +305,26 @@ class Lowering(using TL, Raise, Elaborator.State):
         k(Value.Ref(l))
       )
 
+    // * BbML-specific cases: t.Cls#field and mutable operations
+    case SelProj(prefix, _, proj) =>
+      setupSelection(prefix, proj, N)(k)
+    case Region(reg, body) =>
+      Assign(reg, Instantiate(Select(Value.Ref(State.globalThisSymbol), Tree.Ident("Region"))(N), Nil), term(body)(k))
+    case RegRef(reg, value) =>
+      def rec(as: Ls[st], asr: Ls[Path]): Block = as match
+        case Nil => k(Instantiate(Select(Value.Ref(State.globalThisSymbol), Tree.Ident("Ref"))(N), asr.reverse))
+        case a :: as =>
+          subTerm(a): ar =>
+            rec(as, ar :: asr)
+      rec(reg :: value :: Nil, Nil)
+    case Deref(ref) =>
+      subTerm(ref): r =>
+        k(Select(r, Tree.Ident("value"))(N))
+    case SetRef(lhs, rhs) =>
+      subTerm(lhs): ref =>
+        subTerm(rhs): value =>
+          AssignField(ref, Tree.Ident("value"), value, k(value))(N)
+
     case Error => End("error")
 
     // case _ =>

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

@@ -93,6 +93,12 @@ class JSBuilder(using Elaborator.State, Elaborator.Ctx) extends CodeBuilder:
     case Call(Value.Ref(l: BuiltinSymbol), args) =>
       err(msg"Illeal arity for builtin symbol '${l.nme}'")
 
+    case Call(s @ Select(_, id), lhs :: rhs :: Nil) =>
+      Elaborator.ctx.Builtins.getBuiltinOp(id.name) match
+        case S(jsOp) =>
+          val res = doc"${result(lhs)} ${jsOp} ${result(rhs)}"
+          if needsParens(jsOp) then doc"(${res})" else res
+        case N => doc"${result(s)}(${(result(lhs) :: result(rhs) :: Nil).mkDocument(", ")})"
     case c @ Call(fun, args) =>
       val base = fun match
         case _: Value.Lam => doc"(${result(fun)})"
@@ -148,7 +154,7 @@ class JSBuilder(using Elaborator.State, Elaborator.Ctx) extends CodeBuilder:
             S(defn.sym).collectFirst{ case s: InnerSymbol => s }):
           defn match
           case FunDefn(sym, Nil, body) =>
-            TODO("getters")
+            doc"function ${sym.nme}() { #{  # ${this.body(body)} #}  # }"
           case FunDefn(sym, ps :: pss, bod) =>
             val result = pss.foldRight(bod):
               case (ps, block) => 
@@ -179,6 +185,10 @@ class JSBuilder(using Elaborator.State, Elaborator.Ctx) extends CodeBuilder:
                     doc" # ${td.sym.nme}($params) { #{  # ${
                       bodyDoc
                     } #}  # }"
+                  case td @ FunDefn(_, Nil, bod) =>
+                    doc" # get ${td.sym.nme}() { #{  # ${
+                      this.body(bod)
+                    } #}  # }"
                 .mkDocument(" ")
               }${
                 if mtds.exists(_.sym.nme == "toString")

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

@@ -29,7 +29,10 @@ object Elaborator:
     ";" -> ",",
     "+." -> "+",
     "-." -> "-",
-    "*." -> "*")
+    "*." -> "*",
+    "/." -> "/")
+  private val builtinBinOps = aliasOps ++ (binaryOps.map: op =>
+    op -> op).toMap
 
   val reservedNames = binaryOps.toSet ++ aliasOps.keySet + "NaN" + "Infinity"
 
@@ -43,11 +46,15 @@ object Elaborator:
 
     def withMembers(members: Iterable[Str -> MemberSymbol[?]], out: Opt[Symbol] = N): Ctx =
       copy(env = env ++ members.map:
-        case (nme, sym) => nme -> (
-          out orElse outer match
-          case S(outer) => Ctx.SelElem(outer, sym.nme, S(sym))
-          case N => sym: Ctx.Elem
-        )
+        case (nme, sym) =>
+          val elem = out orElse outer match
+            case S(outer) => Ctx.SelElem(outer, sym.nme, S(sym))
+            case N => sym: Ctx.Elem
+          if sym.isGetter && !(out.exists:
+            case _: ClassSymbol | _: ModuleSymbol => true // * A getter inside class/module can be invoked directly
+            case _: BlockMemberSymbol | _: TermSymbol | _: TypeAliasSymbol | _: PatternSymbol | _: TopLevelSymbol => false)
+          then nme -> Ctx.GetElem(elem)
+          else nme -> elem
       )
 
     def nest(outer: Opt[InnerSymbol]): Ctx = Ctx(outer, Some(this), Map.empty)
@@ -78,25 +85,32 @@ object Elaborator:
       val Num = assumeBuiltinCls("Num")
       val Str = assumeBuiltinCls("Str")
       val Predef = assumeBuiltinMod("Predef")
+      def getBuiltinOp(op: Str): Opt[Str] = if getBuiltin(op).isDefined then builtinBinOps.get(op) else N
 
   object Ctx:
     abstract class Elem:
       def nme: Str
-      def ref(id: Tree.Ident): Term
+      def ref(id: Tree.Ident)(using Elaborator.State): Term
       def symbol: Opt[Symbol]
     final case class RefElem(val sym: Symbol) extends Elem:
       val nme = sym.nme
-      def ref(id: Tree.Ident): Term =
+      def ref(id: Tree.Ident)(using Elaborator.State): Term =
         require(id.name == nme)
         Term.Ref(sym)(id, 666) // TODO 666
       def symbol = S(sym)
     final case class SelElem(val base: Elem, val nme: Str, val symOpt: Opt[FieldSymbol]) extends Elem:
-      def ref(id: Tree.Ident): Term =
+      def ref(id: Tree.Ident)(using Elaborator.State): Term =
         // * Note: due to symbolic ops, we may have `id.name =/= nme`;
         // * e.g., we can have `id.name = "|>"` and `nme = "pipe"`.
         Term.SynthSel(base.ref(Ident(base.nme)),
           new Tree.Ident(nme).withLocOf(id))(symOpt)
       def symbol = symOpt
+    final case class GetElem(val base: Elem) extends Elem:
+      def nme: Str = base.nme
+      def ref(id: Tree.Ident)(using Elaborator.State): Term =
+        val emptyTup: Tree.Tup = Tree.Tup(Nil)
+        Term.App(base.ref(id), Term.Tup(Nil)(emptyTup))(Tree.App(id, emptyTup), FlowSymbol("‹get-res›"))
+      def symbol: Opt[Symbol] = base.symbol
     given Conversion[Symbol, Elem] = RefElem(_)
     val empty: Ctx = Ctx(N, N, Map.empty)
 
@@ -273,7 +287,7 @@ extends Importer:
     case App(Ident("&"), Tree.Tup(lhs :: rhs :: Nil)) =>
       Term.CompType(term(lhs), term(rhs), false)
     case App(Ident(":="), Tree.Tup(lhs :: rhs :: Nil)) =>
-      Term.Assgn(term(lhs), term(rhs))
+      Term.SetRef(term(lhs), term(rhs))
     case App(Ident("#"), Tree.Tup(SynthSel(pre, idn: Ident) :: (idp: Ident) :: Nil)) =>
       Term.SelProj(term(pre), term(idn), idp)
     case App(Ident("#"), Tree.Tup(SynthSel(pre, Ident(name)) :: App(Ident(proj), args) :: Nil)) =>

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

@@ -116,12 +116,16 @@ class BlockMemberSymbol(val nme: Str, val trees: Ls[Tree])(using State)
   override def toString: Str =
     s"member:$nme${State.dbgUid(uid)}"
 
+  override val isGetter: Bool = // TODO: this should be checked based on a special syntax for getter
+    trmImplTree.exists(t => t.k === Fun && t.paramLists.isEmpty)
+
 end BlockMemberSymbol
 
 
 sealed abstract class MemberSymbol[Defn <: Definition](using State) extends Symbol:
   def nme: Str
   var defn: Opt[Defn] = N
+  val isGetter: Bool = false
 
 
 class TermSymbol(val k: TermDefKind, val owner: Opt[InnerSymbol], val id: Tree.Ident)(using State)

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

@@ -35,6 +35,7 @@ enum Term extends Statement:
   case RegRef(reg: Term, value: Term)
   case Assgn(lhs: Term, rhs: Term)
   case Deref(ref: Term)
+  case SetRef(ref: Term, value: Term)
   case Ret(result: Term)
   case Throw(result: Term)
   case Try(body: Term, finallyDo: Term)
@@ -71,7 +72,9 @@ enum Term extends Statement:
     case Region(name, body) => "region expression"
     case RegRef(reg, value) => "reference creation"
     case Assgn(lhs, rhs) => "assignment"
+    case SetRef(ref, value) => "mutable reference assignment"
     case Deref(ref) => "dereference"
+    case Throw(e) => "throw"
 end Term
 
 import Term.*
@@ -111,6 +114,7 @@ sealed trait Statement extends AutoLocated with ProductWithExtraInfo:
     case Region(_, body) => body :: Nil
     case RegRef(reg, value) => reg :: value :: Nil
     case Assgn(lhs, rhs) => lhs :: rhs :: Nil
+    case SetRef(lhs, rhs) => lhs :: rhs :: Nil
     case Deref(term) => term :: Nil
     case TermDefinition(_, k, _, ps, sign, body, res, _) =>
       ps.toList.flatMap(_.subTerms) ::: sign.toList ::: body.toList
@@ -180,6 +184,7 @@ sealed trait Statement extends AutoLocated with ProductWithExtraInfo:
     case Region(name, body) => s"region ${name.nme} in ${body.showDbg}"
     case RegRef(reg, value) => s"(${reg.showDbg}).ref ${value.showDbg}"
     case Assgn(lhs, rhs) => s"${lhs.showDbg} := ${rhs.showDbg}"
+    case SetRef(lhs, rhs) => s"${lhs.showDbg} := ${rhs.showDbg}"
     case Deref(term) => s"!$term"
     case CompType(lhs, rhs, pol) => s"${lhs.showDbg} ${if pol then "|" else "&"} ${rhs.showDbg}"
     case Error => "<error>"

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

@@ -50,7 +50,7 @@ const Predef$class = class Predef {
           tmp = "| ".repeat(this.indentLvl) ?? null;
           tmp1 = "  ".repeat(this.indentLvl) ?? null;
           tmp2 = "\n" + tmp1;
-          tmp3 = msg.replaceAll("\n", tmp2) ?? null;
+          tmp3 = msg.replaceAll("\n", tmp2);
           tmp4 = tmp + tmp3;
           return console.log(tmp4) ?? null;
         } else {
@@ -88,7 +88,7 @@ const Predef$class = class Predef {
   } 
   call(receiver1, f2) {
     return (...args) => {
-      return f2.call(receiver1, ...args) ?? null;
+      return f2.call(receiver1, ...args);
     };
   } 
   print(x3) {
@@ -102,7 +102,7 @@ const Predef$class = class Predef {
     return globalThis.Array.prototype.slice.call(xs, i, tmp) ?? null;
   } 
   tupleGet(xs1, i1) {
-    return globalThis.Array.prototype.at.call(xs1, i1) ?? null;
+    return globalThis.Array.prototype.at.call(xs1, i1);
   } 
   stringStartsWith(string, prefix) {
     return string.startsWith(prefix) ?? null;

hkmc2/shared/src/test/mlscript-compile/apps/Accounting.mjs

@@ -63,15 +63,15 @@ class Accounting {
       constructor(fileName) {
         this.fileName = fileName;
         let tmp;
-        tmp = fs.writeFileSync(this.fileName, "# Accounting\n") ?? null;
+        tmp = fs.writeFileSync(this.fileName, "# Accounting\n");
       }
       w(txt) {
-        return fs.appendFileSync(this.fileName, txt) ?? null;
+        return fs.appendFileSync(this.fileName, txt);
       } 
       wln(txt1) {
         let tmp;
         tmp = Str.concat(txt1, "\n");
-        return fs.appendFileSync(this.fileName, tmp) ?? null;
+        return fs.appendFileSync(this.fileName, tmp);
       } 
       init() {
         let tmp, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8, tmp9, tmp10, tmp11, tmp12, tmp13;
@@ -134,7 +134,7 @@ class Accounting {
         }) ?? null;
         tmp14 = tmp13.reduce((a, b) => {
           return a + b;
-        }, 0) ?? null;
+        }, 0);
         tmp15 = this$Accounting.display(tmp14);
         tmp16 = Str.concat(tmp11, tmp15);
         tmp17 = Str.concat(tmp16, "|");
@@ -149,7 +149,7 @@ class Accounting {
         }) ?? null;
         tmp23 = tmp22.reduce((a, b) => {
           return a + b;
-        }, 0) ?? null;
+        }, 0);
         tmp24 = this$Accounting.display(tmp23);
         tmp25 = Str.concat(tmp20, tmp24);
         tmp26 = Str.concat(tmp25, "|");