Multi line chained operator syntax (#8415)

engine/runtime-parser/src/main/java/org/enso/compiler/core/TreeToIr.java

@@ -552,7 +552,7 @@ final class TreeToIr {
         method = buildName(id);
         loc = getIdentifiedLocation(sig);
       }
-      case Tree.OprApp app when ".".equals(app.getOpr().getRight().codeRepr()) -> {
+      case Tree.OprApp app when isDotOperator(app.getOpr().getRight()) -> {
         type = Option.apply(buildQualifiedName(app.getLhs()));
         method = buildName(app.getRhs());
         if (alwaysLocation) {
@@ -568,7 +568,7 @@ final class TreeToIr {
     );
   }
 
-  private Expression translateCall(Tree ast) {
+  private Expression translateCall(Tree ast, boolean isMethod) {
     var args = new java.util.ArrayList<CallArgument>();
     var hasDefaultsSuspended = false;
     var tree = ast;
@@ -597,25 +597,48 @@ final class TreeToIr {
           args.add(new CallArgument.Specified(Option.empty(), expr, loc, meta(), diag()));
           tree = app.getFunc();
         }
+        case Tree.OperatorBlockApplication app -> {
+          var at = args.size();
+          var self = translateExpression(app.getLhs(), false);
+          for (var l : app.getExpressions()) {
+            var invoke = isDotOperator(l.getExpression().getOperator().getRight());
+            if (self == null || !invoke) {
+              return null;
+            }
+            var expr = switch (translateExpression(l.getExpression().getExpression(), true)) {
+              case Application.Prefix pref -> {
+                var arg = new CallArgument.Specified(Option.empty(), self, self.location(), meta(), diag());
+                yield new Application.Prefix(pref.function(), join(arg, pref.arguments()), false, pref.location(), meta(), diag());
+              }
+              case Expression any -> {
+                var arg = new CallArgument.Specified(Option.empty(), self, self.location(), meta(), diag());
+                yield new Application.Prefix(any, join(arg, nil()), false, any.location(), meta(), diag());
+              }
+            };
+            var loc = getIdentifiedLocation(l.getExpression().getExpression());
+            args.add(at, new CallArgument.Specified(Option.empty(), expr, loc, meta(), diag()));
+            self = expr;
+          }
+          return self;
+        }
         default -> {
           Expression func;
           if (tree instanceof Tree.OprApp oprApp
-                  && oprApp.getOpr().getRight() != null
-                  && ".".equals(oprApp.getOpr().getRight().codeRepr())
+                  && isDotOperator(oprApp.getOpr().getRight())
                   && oprApp.getRhs() instanceof Tree.Ident) {
             func = translateExpression(oprApp.getRhs(), true);
             if (oprApp.getLhs() == null && args.isEmpty()) {
               return func;
             }
             if (oprApp.getLhs() != null) {
-              var self = translateExpression(oprApp.getLhs(), false);
+              var self = translateExpression(oprApp.getLhs(), isMethod);
               var loc = getIdentifiedLocation(oprApp.getLhs());
               args.add(new CallArgument.Specified(Option.empty(), self, loc, meta(), diag()));
             }
           } else if (args.isEmpty()) {
             return null;
           } else {
-            func = translateExpression(tree, false);
+            func = translateExpression(tree, isMethod);
           }
           java.util.Collections.reverse(args);
           var argsList = CollectionConverters.asScala(args.iterator()).toList();
@@ -682,7 +705,7 @@ final class TreeToIr {
     if (tree == null) {
       return null;
     }
-    var callExpression = translateCall(tree);
+    var callExpression = translateCall(tree, isMethod);
     if (callExpression != null) {
       return callExpression;
     }
@@ -750,22 +773,27 @@ final class TreeToIr {
           default -> {
             var lhs = unnamedCallArgument(app.getLhs());
             var rhs = unnamedCallArgument(app.getRhs());
-            var name = new Name.Literal(
-              op.codeRepr(), true, getIdentifiedLocation(op), Option.empty(), meta(), diag()
-            );
             var loc = getIdentifiedLocation(app);
-            if (lhs == null && rhs == null) {
-              yield new Section.Sides(name, loc, meta(), diag());
-            } else if (lhs == null) {
-              yield new Section.Right(name, rhs, loc, meta(), diag());
-            } else if (rhs == null) {
-              yield new Section.Left(lhs, name, loc, meta(), diag());
-            } else {
-              yield new Operator.Binary(lhs, name, rhs, loc,meta(), diag());
-            }
+            yield applyOperator(op, lhs, rhs, loc);
           }
         };
       }
+      case Tree.OperatorBlockApplication app -> {
+        Expression expr = null;
+        var lhs = unnamedCallArgument(app.getLhs());
+        for (var l : app.getExpressions()) {
+          var op = l.getExpression().getOperator().getRight();
+          if (op == null || isDotOperator(op)) {
+            yield translateSyntaxError(l.getExpression().getExpression(), Syntax.UnexpectedExpression$.MODULE$);
+          }
+          var rhs = unnamedCallArgument(l.getExpression().getExpression());
+          var loc = getIdentifiedLocation(app);
+          var both = applyOperator(op, lhs, rhs, loc);
+          expr = both;
+          lhs = new CallArgument.Specified(Option.empty(), expr, loc, meta(), diag());
+        }
+        yield expr;
+      }
       case Tree.Array arr -> {
         List<Expression> items = nil();
         if (arr.getFirst() != null) {
@@ -998,6 +1026,21 @@ final class TreeToIr {
     };
   }
 
+  private Operator applyOperator(Token.Operator op, CallArgument lhs, CallArgument rhs, Option<IdentifiedLocation> loc) {
+    var name = new Name.Literal(
+      op.codeRepr(), true, getIdentifiedLocation(op), Option.empty(), meta(), diag()
+    );
+    if (lhs == null && rhs == null) {
+      return new Section.Sides(name, loc, meta(), diag());
+    } else if (lhs == null) {
+      return new Section.Right(name, rhs, loc, meta(), diag());
+    } else if (rhs == null) {
+      return new Section.Left(lhs, name, loc, meta(), diag());
+    } else {
+      return new Operator.Binary(lhs, name, rhs, loc,meta(), diag());
+    }
+  }
+
   Tree applySkip(Tree tree) {
     // Termination:
     // Every iteration either breaks, or reduces [`tree`] to a substructure of [`tree`].
@@ -1360,7 +1403,7 @@ final class TreeToIr {
         );
       }
       case Tree.Ident id -> new Pattern.Name(buildName(id), getIdentifiedLocation(id), meta(), diag());
-      case Tree.OprApp app when ".".equals(app.getOpr().getRight().codeRepr()) -> {
+      case Tree.OprApp app when isDotOperator(app.getOpr().getRight()) -> {
         var qualifiedName = buildQualifiedName(app);
         yield new Pattern.Constructor(
           qualifiedName, fields, getIdentifiedLocation(app), meta(), diag()
@@ -1795,6 +1838,10 @@ final class TreeToIr {
     return scala.collection.immutable.$colon$colon$.MODULE$.apply(head, tail);
   }
 
+  private static boolean isDotOperator(Token.Operator op) {
+    return op != null && ".".equals(op.codeRepr());
+  }
+
   private static Tree maybeManyParensed(Tree t) {
     for (;;) {
       switch (t) {

engine/runtime-parser/src/test/java/org/enso/compiler/core/EnsoParserTest.java

@@ -1245,6 +1245,62 @@ public class EnsoParserTest {
     equivalenceTest("a = x", "a = SKIP FREEZE x.f y");
   }
 
+  @Test
+  public void testBlockSyntax() throws Exception {
+    equivalenceTest("""
+    nums v fm ff n = v . map fm . filter ff . take n
+    """, """
+    nums v fm ff n = v
+        . map fm
+        . filter ff
+        . take n
+    """);
+  }
+
+  @Test
+  public void testBlockSyntaxOperators() throws Exception {
+    equivalenceTest("""
+    value = nums * each random + constant
+    """, """
+    value = nums
+        * each random
+        + constant
+    """);
+  }
+
+  @Test
+  public void testBlockSyntaxOperators2() throws Exception {
+    equivalenceTest("""
+    value = (nums + each random) * constant
+    """, """
+    value = nums
+        + each random
+        * constant
+    """);
+  }
+
+  @Test
+  public void testBlockSyntaxOperators3() throws Exception {
+    equivalenceTest("""
+    v = (rect1 . width) . center
+    """, """
+    v = rect1
+        . width
+        . center
+    """);
+  }
+
+  @Test
+  public void testBlockSyntaxOperators4() throws Exception {
+    equivalenceTest("""
+    v = (rect1 . width 4) . center 3 2
+    """, """
+    v = rect1
+        . width 4
+        . center 3 2
+    """);
+  }
+
   @Test
   public void testPrivateModules() throws Exception {
     List<String> moduleCodes = List.of(

engine/runtime/src/test/java/org/enso/compiler/ExecCompilerTest.java

@@ -126,6 +126,35 @@ public class ExecCompilerTest {
     }
   }
 
+  @Test
+  public void chainedSyntax() throws Exception {
+    var module = ctx.eval("enso", """
+    from Standard.Base import all
+
+    nums n = [1, 2, 3, 4, 5]
+        . map (x-> x*2)
+        . filter (x-> x % 3 == 0)
+        . take n
+    """);
+    var run = module.invokeMember("eval_expression", "nums");
+    var six = run.execute(1);
+    assertTrue(six.hasArrayElements());
+    assertEquals(1, six.getArraySize());
+    assertEquals(6, six.getArrayElement(0).asInt());
+  }
+
+  @Test
+  public void chainedSyntaxOperator() throws Exception {
+    var module = ctx.eval("enso", """
+    nums n = n
+        * 2
+        % 3
+    """);
+    var run = module.invokeMember("eval_expression", "nums");
+    var result = run.execute(5);
+    assertEquals("10 % 3 is one", 1, result.asInt());
+  }
+
   @Test
   public void testInvalidEnsoProjectRef() throws Exception {
     var module =