Parse capture annotation syntax for (extern) function definitions (#1109)

Resolves #1106

```
extern? <CAPTURES> def ... : ... = ...
```

becomes

```
extern? def ... at <CAPTURES> : ... = ...
```

or to say it in terms of a regex

```
/(^( *extern) *(\w+|\{ *((\w+ *, *)| *\w+ *)* *\}) *)(?=def )(.*)(: *.*)$/gm

$2 $6 at $3$7
```

---------

Co-authored-by: Jonathan Brachthäuser <[email protected]>

Author: dvdvgt

effekt/js/src/test/scala/effekt/WebTests.scala

@@ -43,7 +43,7 @@ object WebTests extends TestSuite {
      */
     def evaluate[A](includes: List[String], content: String): A =
       run(includes,
-        s"""|extern io def withResult[A](value: A): Unit = js"(function() { module.exports.result = $${value} })()"
+        s"""|extern def withResult[A](value: A) at io: Unit = js"(function() { module.exports.result = $${value} })()"
             |def main() = { withResult(${content}) }
             |""".stripMargin)
       js.Dynamic.global.globalThis.module.`exports`.result.asInstanceOf[A]

effekt/jvm/src/main/scala/effekt/Repl.scala

@@ -321,7 +321,7 @@ class Repl(driver: Driver) extends REPL[Tree, EffektConfig, EffektError] {
       val fakeSpan = Span(source, 0, 0, origin = Origin.Synthesized)
       val fullSpan = Span(source, 0, source.content.length, origin = Origin.Synthesized)
       ModuleDecl("interactive", includes,
-        definitions :+ FunDef(IdDef(defName, fakeSpan), Many.empty(fakeSpan), Many.empty(fakeSpan), Many.empty(fakeSpan), Maybe.None(fakeSpan),
+        definitions :+ FunDef(IdDef(defName, fakeSpan), Many.empty(fakeSpan), Many.empty(fakeSpan), Many.empty(fakeSpan), Maybe.None(fakeSpan), Maybe.None(fakeSpan),
           body, Info.empty(fakeSpan), fullSpan), None, fullSpan)
     }
 

effekt/jvm/src/test/scala/effekt/LSPTests.scala

@@ -1300,6 +1300,10 @@ class LSPTests extends FunSuite {
              |        None(),
              |        Span(StringSource(def main() = <>, file://test.effekt), 10, 10, Real())
              |      ),
+             |      Maybe(
+             |        None(),
+             |        Span(StringSource(def main() = <>, file://test.effekt), 10, 10, Real())
+             |      ),
              |      Return(
              |        Hole(
              |          IdDef(
@@ -1325,8 +1329,7 @@ class LSPTests extends FunSuite {
              |        Maybe(
              |          None(),
              |          Span(StringSource(def main() = <>, file://test.effekt), 0, 0, Real())
-             |        ),
-             |        None()
+             |        )
              |      ),
              |      Span(StringSource(def main() = <>, file://test.effekt), 0, 15, Real())
              |    )

effekt/jvm/src/test/scala/effekt/ParserTests.scala

@@ -145,7 +145,7 @@ class ParserTests extends munit.FunSuite {
     parse(input, _.externDef())
 
   def parseInfo(input: String)(using munit.Location): Info =
-    parse(input, _.info(parseCaptures = true))
+    parse(input, _.info())
 
   // Custom asserts
   //
@@ -545,6 +545,7 @@ class ParserTests extends munit.FunSuite {
     parseStmts("val (left, right) = list; return left")
 
     parseStmts("val g: () => Unit / Exc at {exc} = fun() { closure() }; ()")
+    parseStmts("val g: () => Unit / Exc at exc = fun() { closure() }; ()")
   }
 
   test("Pattern-matching val parses with correct span") {
@@ -982,6 +983,7 @@ class ParserTests extends munit.FunSuite {
         DefDef(
           IdDef("foo", Span(source, pos(0), pos(1))),
           Maybe.None(Span(source, pos(1), pos(1))),
+          Maybe.None(Span(source, pos(1), pos(1))),
           Var(IdRef(Nil, "f", Span(source, pos(2), pos(3))), Span(source, pos(2), pos(3))),
           Info.empty(Span(source, 0, 0)),
           Span(source, 0, pos.last)))
@@ -1013,6 +1015,12 @@ class ParserTests extends munit.FunSuite {
     )
   }
 
+  test("Function definition with capture set") {
+    parseDefinition("def foo(v: Int) at {}: Unit = <>")
+    parseDefinition("def foo(v: Int) at io: Unit = <>")
+    parseDefinition("def foo(v: Int) at {async, io}: Unit = <>")
+  }
+
   test("Function definition"){
     val (source, pos) =
       raw"""def foo[T1, T2](x: T1, y: T2){b: => Unit}: Unit = <>
@@ -1022,7 +1030,7 @@ class ParserTests extends munit.FunSuite {
     val definition = parseDefinition(source.content)
 
     val funDef = definition match {
-      case fd@FunDef(id, tparams, vparams, bparams, ret, body, doc, span) => fd
+      case fd@FunDef(id, tparams, vparams, bparams, captures, ret, body, doc, span) => fd
       case other =>
         throw new IllegalArgumentException(s"Expected FunDef but got ${other.getClass.getSimpleName}")
     }
@@ -1041,7 +1049,7 @@ class ParserTests extends munit.FunSuite {
     val definition = parseDefinition(source.content)
 
     val funDef = definition match {
-      case fd@FunDef(id, tparams, vparams, bparams, ret, body, doc, span) => fd
+      case fd@FunDef(id, tparams, vparams, bparams, captures, ret, body, doc, span) => fd
       case other =>
         throw new IllegalArgumentException(s"Expected FunDef but got ${other.getClass.getSimpleName}")
     }
@@ -1058,7 +1066,7 @@ class ParserTests extends munit.FunSuite {
     val definition = parseDefinition(source.content)
 
     val funDef = definition match {
-      case fd@FunDef(id, tparams, vparams, bparams, ret, body, doc, span) => fd
+      case fd@FunDef(id, tparams, vparams, bparams, captures, ret, body, doc, span) => fd
       case other =>
         throw new IllegalArgumentException(s"Expected FunDef but got ${other.getClass.getSimpleName}")
     }
@@ -1086,7 +1094,7 @@ class ParserTests extends munit.FunSuite {
     val definition = parseDefinition(source.content)
 
     val funDef = definition match {
-      case fd@FunDef(id, tparams, vparams, bparams, ret, body, doc, span) => fd
+      case fd@FunDef(id, tparams, vparams, bparams, captures, ret, body, doc, span) => fd
       case other =>
         throw new IllegalArgumentException(s"Expected FunDef but got ${other.getClass.getSimpleName}")
     }
@@ -1130,45 +1138,41 @@ class ParserTests extends munit.FunSuite {
     assertEquals(valDef.span, span)
   }
 
-  test("Declaration info with capture set") {
+  test("Declaration info with comment and extern") {
     val (source, pos) =
       raw"""/// Some doc comment
-           |private extern {a, b, c}
-           |↑      ↑↑     ↑↑        ↑
+           |private extern
+           |↑      ↑↑     ↑
            |""".sourceAndPositions
 
     parseInfo(source.content) match {
       case Info(
           Some(doc),
           isPrivate,
           isExtern,
-          Some(CaptureSet(captures, Span(_, captFrom, captTo, _)))) =>
+        ) =>
 
         assertEquals(doc, " Some doc comment")
         assertEquals(isPrivate, Maybe(Some(()), Span(source, pos(0), pos(1))))
         assertEquals(isExtern, Maybe(Some(()), Span(source, pos(2), pos(3))))
-        assertEquals(captures.map(_.name), List("a", "b", "c"))
-        assertEquals(captFrom, pos(4))
-        assertEquals(captTo, pos(5))
 
       case info => fail(s"Wrong info: ${info}")
     }
   }
 
-  test("Only private") {
+  test("Only comment and private") {
     val (source, pos) =
       raw"""/// Some doc comment
            |private
            |↑      ↑
            |""".sourceAndPositions
 
     parseInfo(source.content) match {
-      case Info(doc, isPrivate, isExtern, externCapture) =>
+      case Info(doc, isPrivate, isExtern) =>
 
         assertEquals(doc, Some(" Some doc comment"))
         assertEquals(isPrivate, Maybe(Some(()), Span(source, pos(0), pos(1))))
         assertEquals(isExtern, Maybe(None, Span(source, pos(1), pos(1))))
-        assertEquals(externCapture, None)
     }
   }
 
@@ -1179,11 +1183,10 @@ class ParserTests extends munit.FunSuite {
            |""".sourceAndPositions
 
     parseInfo(source.content) match {
-      case Info(doc, isPrivate, isExtern, externCapture) =>
+      case Info(doc, isPrivate, isExtern) =>
         assertEquals(doc, Some(" Some doc comment"))
         assertEquals(isPrivate, Maybe(None, Span(source, pos(0), pos(0))))
         assertEquals(isExtern, Maybe(None, Span(source, pos(0), pos(0))))
-        assertEquals(externCapture, None)
     }
   }
 
@@ -1587,7 +1590,7 @@ class ParserTests extends munit.FunSuite {
   }
 
   test("Extern definition") {
-    parseExternDef("extern {io} def read(s: String): Int = default { 42 } js { 1 + 1 } chez { 42 }")
+    parseExternDef("extern def read(s: String) at {io}: Int = default { 42 } js { 1 + 1 } chez { 42 }")
     parseExternDef("extern \"console.log(42)\"")
     parseExternDef("extern \"\"\"console.log(42)\"\"\"")
     parseExternDef("extern type Complex")
@@ -1596,7 +1599,7 @@ class ParserTests extends munit.FunSuite {
     parseExternDef("extern resource withFile: [A](String) { () => A } => A")
     parseExternDef("extern include \"path/to/file\"")
     parseExternDef("extern js \"\"\"console.log(42)\"\"\"")
-    parseExternDef("extern pure def read(s: String): String = default { s }")
+    parseExternDef("extern def read(s: String) at {}: String = default { s }")
     parseExternDef("extern def read(s: String): String = \"${s}\"")
     parseProgram(
       "extern def println(value: String): Unit =" +

effekt/shared/src/main/scala/effekt/Intelligence.scala

@@ -127,7 +127,7 @@ trait Intelligence {
         p.productElementNames.zip(p.productIterator)
           .collectFirst {
             case ("doc", Some(s: String)) => s
-            case ("info", source.Info(Some(s: String), _, _, _)) => s
+            case ("info", source.Info(Some(s: String), _, _)) => s
           }
       case _ => None
   }

effekt/shared/src/main/scala/effekt/Lexer.scala

@@ -141,7 +141,6 @@ enum TokenKind {
   case `and`
   case `is`
   case `namespace`
-  case `pure`
 
   case `module`
   case `import`
@@ -180,7 +179,7 @@ object TokenKind {
     `let`, `true`, `false`, `val`, `var`, `if`, `else`, `while`, `type`, `effect`, `interface`,
     `try`, `with`, `case`, `do`, `fun`, `match`, `def`, `module`, `import`, `export`, `extern`,
     `include`, `record`, `box`, `unbox`, `return`, `region`, `resource`, `new`, `and`, `is`,
-    `namespace`, `pure`, `private`
+    `namespace`, `private`
   )
 
   val keywordMap: immutable.HashMap[String, TokenKind] =

effekt/shared/src/main/scala/effekt/Namer.scala

@@ -135,17 +135,18 @@ object Namer extends Phase[Parsed, NameResolved] {
       }
 
     // allow recursive definitions of objects
-    case d @ source.DefDef(id, annot, source.New(source.Implementation(interface, clauses, _), _), doc, span) =>
+    case d @ source.DefDef(id, captures, annot, source.New(source.Implementation(interface, clauses, _), _), doc, span) =>
       val tpe = Context.at(interface) { resolveBlockRef(interface) }
-      val sym = Binder.DefBinder(Context.nameFor(id), Some(tpe), d)
+      val cpts = captures.unspan.map { resolve }
+      val sym = Binder.DefBinder(Context.nameFor(id), cpts, Some(tpe), d)
       Context.define(id, sym)
 
-    case d @ source.DefDef(id, annot, block, doc, span) =>
+    case d @ source.DefDef(id, captures, annot, block, doc, span) =>
       ()
 
-    case f @ source.FunDef(id, tparams, vparams, bparams, annot, body, doc, span) =>
+    case f @ source.FunDef(id, tparams, vparams, bparams, captures, annot, body, doc, span) =>
       val uniqueId = Context.nameFor(id)
-
+      val cpts = captures.map { resolve }.unspan
       // we create a new scope, since resolving type params introduces them in this scope
       val sym = Context scoped {
         val tps = tparams map resolve
@@ -158,7 +159,7 @@ object Namer extends Phase[Parsed, NameResolved] {
           Context.bindBlocks(bps)
           annot map resolve
         }
-        UserFunction(uniqueId, tps.unspan, vps.unspan, bps.unspan, ret.unspan.map { _._1 }, ret.unspan.map { _._2 }, f)
+        UserFunction(uniqueId, tps.unspan, vps.unspan, bps.unspan, cpts, ret.unspan.map { _._1 }, ret.unspan.map { _._2 }, f)
       }
       Context.define(id, sym)
 
@@ -219,9 +220,9 @@ object Namer extends Phase[Parsed, NameResolved] {
         ExternInterface(Context.nameFor(id), tps, decl)
       })
 
-    case d @ source.ExternDef(capture, id, tparams, vparams, bparams, ret, bodies, doc, span) => {
+    case d @ source.ExternDef(id, tparams, vparams, bparams, captures, ret, bodies, doc, span) => {
       val name = Context.nameFor(id)
-      val capt = resolve(capture)
+      val capt = resolve(captures)
       Context.define(id, Context scoped {
         val tps = tparams map resolve
         val vps = vparams map resolve
@@ -314,16 +315,17 @@ object Namer extends Phase[Parsed, NameResolved] {
       Context.define(id, sym)
 
     // already has been preresolved (to enable recursive definitions)
-    case d @ source.DefDef(id, annot, source.New(impl, _), doc, span) =>
+    case d @ source.DefDef(id, captures, annot, source.New(impl, _), doc, span) =>
       resolve(impl)
 
-    case d @ source.DefDef(id, annot, binding, doc, span) =>
+    case d @ source.DefDef(id, captures, annot, binding, doc, span) =>
       val tpe = annot.map(resolveBlockType)
       resolve(binding)
-      Context.define(id, DefBinder(Context.nameFor(id), tpe.unspan, d))
+      val cpts = captures.unspan.map { resolve }
+      Context.define(id, DefBinder(Context.nameFor(id), cpts, tpe.unspan, d))
 
     // FunDef and InterfaceDef have already been resolved as part of the module declaration
-    case f @ source.FunDef(id, tparams, vparams, bparams, ret, body, doc, span) =>
+    case f @ source.FunDef(id, tparams, vparams, bparams, captures, ret, body, doc, span) =>
       val sym = f.symbol
       Context.scopedWithName(id.name) {
         sym.tparams.foreach { p => Context.bind(p) }
@@ -333,7 +335,7 @@ object Namer extends Phase[Parsed, NameResolved] {
         resolve(body)
       }
 
-    case f @ source.ExternDef(capture, id, tparams, vparams, bparams, ret, bodies, doc, span) =>
+    case f @ source.ExternDef(id, tparams, vparams, bparams, captures, ret, bodies, doc, span) =>
       val sym = f.symbol
       Context.scopedWithName(id.name) {
         sym.tparams.foreach { p => Context.bind(p) }