Implement connectTo

constraints/src/main/java/gov/nasa/jpl/aerie/constraints/json/ConstraintParsers.java

@@ -593,6 +593,17 @@ static JsonParser<SpansFromWindows> spansFromWindowsF(JsonParser<Expression<Wind
             $ -> tuple(Unit.UNIT, $.expression()));
   }
 
+  static JsonParser<SpansConnectTo> connectTo(JsonParser<Expression<Spans>> spansExpressionP) {
+    return productP
+        .field("kind", literalP("SpansExpressionConnectTo"))
+        .field("from", spansExpressionP)
+        .field("to", spansExpressionP)
+        .map(
+            untuple((kind, from, to) -> new SpansConnectTo(from, to)),
+            $ -> tuple(Unit.UNIT, $.from(), $.to())
+        );
+  }
+
   private static final JsonParser<SpansInterval> spansIntervalP =
       productP
           .field("kind", literalP("SpansExpressionInterval"))
@@ -607,6 +618,7 @@ private static JsonParser<Expression<Spans>> spansExpressionF(JsonParser<Express
           spansIntervalP,
           startsF(selfP),
           endsF(selfP),
+          connectTo(selfP),
           shiftEdgesF(selfP),
           splitF(selfP),
           splitF(windowsP),

constraints/src/main/java/gov/nasa/jpl/aerie/constraints/time/Interval.java

@@ -235,6 +235,30 @@ public boolean isStrictlyBefore(Interval x){
     return compareEndToStart(this,x) < 0;
   }
 
+  public int compareStarts(Interval other) {
+    final var timeComparison = this.start.compareTo(other.start);
+    if (timeComparison != 0) return timeComparison;
+    else if (this.startInclusivity == other.startInclusivity) return 0;
+    else if (this.startInclusivity == Inclusive) return -1;
+    else return 1;
+  }
+
+  public int compareEnds(Interval other) {
+    final var timeComparison = this.end.compareTo(other.end);
+    if (timeComparison != 0) return timeComparison;
+    else if (this.startInclusivity == other.startInclusivity) return 0;
+    else if (this.startInclusivity == Inclusive) return 1;
+    else return -1;
+  }
+
+  public int compareEndToStart(Interval other) {
+    final var timeComparison = this.end.compareTo(other.start);
+    if (timeComparison != 0) return timeComparison;
+    else if (this.endInclusivity != other.startInclusivity) return 0;
+    else if (this.endInclusivity == Inclusive) return 1;
+    else return -1;
+  }
+
   public boolean contains(Duration d){
     return !intersect(this, at(d)).isEmpty();
   }

constraints/src/main/java/gov/nasa/jpl/aerie/constraints/tree/SpansConnectTo.java

@@ -0,0 +1,65 @@
+package gov.nasa.jpl.aerie.constraints.tree;
+
+import gov.nasa.jpl.aerie.constraints.model.EvaluationEnvironment;
+import gov.nasa.jpl.aerie.constraints.model.SimulationResults;
+import gov.nasa.jpl.aerie.constraints.time.Interval;
+import gov.nasa.jpl.aerie.constraints.time.Spans;
+import gov.nasa.jpl.aerie.merlin.protocol.types.Duration;
+
+import java.util.Set;
+import java.util.stream.StreamSupport;
+
+public record SpansConnectTo(Expression<Spans> from, Expression<Spans> to) implements Expression<Spans> {
+
+  @Override
+  public Spans evaluate(final SimulationResults results, final Interval bounds, final EvaluationEnvironment environment) {
+    final var from = this.from.evaluate(results, bounds, environment);
+    final var sortedFrom = StreamSupport.stream(from.spliterator(), true).sorted((l, r) -> l.interval().compareEnds(r.interval())).toList();
+    final var to = this.to.evaluate(results, bounds, environment);
+    final var sortedTo = StreamSupport.stream(to.spliterator(), true).sorted((l, r) -> l.interval().compareStarts(r.interval())).toList();
+    final var result = new Spans();
+    var toIndex = 0;
+    for (final var span: sortedFrom) {
+      final var startTime = span.interval().end;
+      while (toIndex < sortedTo.size() && span.interval().compareEndToStart(sortedTo.get(toIndex).interval()) == 1) {
+        toIndex++;
+      }
+      final Duration endTime;
+      final Interval.Inclusivity endInlusivity;
+      if (toIndex == sortedTo.size()) {
+        endTime = bounds.end;
+        endInlusivity = bounds.endInclusivity;
+      }
+      else {
+        endTime = sortedTo.get(toIndex).interval().start;
+        endInlusivity = Interval.Inclusivity.Inclusive;
+      }
+      result.add(
+          Interval.between(
+              startTime,
+              Interval.Inclusivity.Inclusive,
+              endTime,
+              endInlusivity
+          ),
+          span.value()
+      );
+    }
+    return result;
+  }
+
+  @Override
+  public void extractResources(final Set<String> names) {
+    this.from.extractResources(names);
+    this.to.extractResources(names);
+  }
+
+  @Override
+  public String prettyPrint(final String prefix) {
+    return String.format(
+        "\n%s(connect from %s to %s)",
+        prefix,
+        this.from.prettyPrint(),
+        this.to.prettyPrint()
+    );
+  }
+}

constraints/src/test/java/gov/nasa/jpl/aerie/constraints/tree/ASTTests.java

@@ -1127,6 +1127,68 @@ public void testShiftWindowsEdgesBoundsAdjustment() {
     assertIterableEquals(expected2, result2);
   }
 
+  @Test
+  void testSpansConnectTo() {
+    final var simResults = new SimulationResults(
+        Instant.EPOCH, Interval.between(0, Inclusive, 20, Exclusive, SECONDS),
+        List.of(),
+        Map.of(),
+        Map.of()
+    );
+
+    final var result = new SpansConnectTo(
+        Supplier.of(new Spans(
+            Interval.between(0, 1, SECONDS),
+            Interval.between(5, 7, SECONDS),
+            Interval.between(10, Inclusive, 11, Exclusive, SECONDS),
+            Interval.between(13, 14, SECONDS)
+        )),
+        Supplier.of(new Spans(
+            Interval.between(2, 3, SECONDS),
+            Interval.between(4, 6, SECONDS),
+            Interval.between(8, 9, SECONDS),
+            Interval.between(11, 12, SECONDS)
+        ))
+    ).evaluate(simResults);
+
+    final var expected = new Spans(
+        Interval.between(1, 2, SECONDS),
+        Interval.between(7, 8, SECONDS),
+        Interval.at(11, SECONDS),
+        Interval.between(14, Inclusive, 20, Exclusive, SECONDS)
+    );
+
+    assertIterableEquals(expected, result);
+  }
+
+  @Test
+  void testSpansConnectToMetadata() {
+    final var simResults = new SimulationResults(
+        Instant.EPOCH, Interval.between(0, Inclusive, 20, Exclusive, SECONDS),
+        List.of(),
+        Map.of(),
+        Map.of()
+    );
+
+    final var result = new SpansConnectTo(
+        Supplier.of(new Spans(
+            Segment.of(Interval.between(0, 1, SECONDS), Optional.of(new Spans.Metadata(new ActivityInstance(2, "2", Map.of(), FOREVER)))),
+            Segment.of(Interval.between(5, 7, SECONDS), Optional.empty())
+        )),
+        Supplier.of(new Spans(
+            Interval.between(2, 3, SECONDS),
+            Interval.between(8, 9, SECONDS)
+        ))
+    ).evaluate(simResults);
+
+    final var expected = new Spans(
+        Segment.of(Interval.between(1, 2, SECONDS), Optional.of(new Spans.Metadata(new ActivityInstance(2, "2", Map.of(), FOREVER)))),
+        Segment.of(Interval.between(7, 8, SECONDS), Optional.empty())
+    );
+
+    assertIterableEquals(expected, result);
+  }
+
   @Test
   public void testRollingThresholdExcess() {
     final var simResults = new SimulationResults(

merlin-server/constraints-dsl-compiler/src/libs/constraints-ast.ts

@@ -27,6 +27,7 @@ export enum NodeKind {
   WindowsExpressionFromSpans = 'WindowsExpressionFromSpans',
   SpansExpressionFromWindows = 'SpansExpressionFromWindows',
   SpansExpressionSplit = 'SpansExpressionSplit',
+  SpansExpressionConnectTo = 'SpansExpressionConnectTo',
   SpansExpressionInterval = 'SpansExpressionInterval',
   SpansSelectWhenTrue = 'SpansSelectWhenTrue',
   ExpressionEqual = 'ExpressionEqual',
@@ -122,8 +123,9 @@ export type SpansExpression =
   | IntervalsExpressionShiftEdges
   | SpansExpressionFromWindows
   | ForEachActivitySpans
-  | SpansExpressionInterval
-  | SpansSelectWhenTrue;
+  | SpansSelectWhenTrue
+  | SpansExpressionConnectTo
+  | SpansExpressionInterval;
 
 export interface SpansSelectWhenTrue {
   kind: NodeKind.SpansSelectWhenTrue,
@@ -250,6 +252,12 @@ export interface SpansExpressionSplit {
   internalEndInclusivity: API.Inclusivity
 }
 
+export interface SpansExpressionConnectTo {
+  kind: NodeKind.SpansExpressionConnectTo,
+  from: SpansExpression,
+  to: SpansExpression
+}
+
 export interface SpansExpressionInterval {
   kind: NodeKind.SpansExpressionInterval,
   interval: IntervalExpression

merlin-server/constraints-dsl-compiler/src/libs/constraints-edsl-fluent-api.ts

@@ -451,6 +451,28 @@ export class Spans {
     })
   }
 
+  /**
+   * Connects the end of each of these spans to the start of the nearest span in the argument.
+   *
+   * This operation creates a new spans object. For each span `s` in `this`, it produces a span from
+   * the end of `s` to the start of the first span in `other` that occurs after the end of `s`.
+   *
+   * If `s` and the nearest subsequent span in `other` meet exactly, with no intersection and no
+   * space between them, a singleton span (containing exactly one time) is still created at the meeting point.
+   *
+   * If there are no spans in `other` that occur after `s`, a span is still created from the end of `s` until the
+   * end of the plan.
+   *
+   * @param other
+   */
+  public connectTo(other: Spans): Spans {
+    return new Spans({
+      kind: AST.NodeKind.SpansExpressionConnectTo,
+      from: this.__astNode,
+      to: other.__astNode
+    })
+  }
+
   /**
    * Replaces each Span with its start point.
    */
@@ -1335,6 +1357,22 @@ declare global {
      */
     public static FromInterval(interval: Interval): Spans;
 
+    /**
+     * Connects the end of each of these spans to the start of the nearest span in the argument.
+     *
+     * This operation creates a new spans object. For each span `s` in `this`, it produces a span from
+     * the end of `s` to the start of the first span in `other` that occurs after the end of `s`.
+     *
+     * If `s` and the nearest subsequent span in `other` meet exactly, with no intersection and no
+     * space between them, a singleton span (containing exactly one time) is still created at the meeting point.
+     *
+     * If there are no spans in `other` that occur after `s`, a span is still created from the end of `s` until the
+     * end of the plan.
+     *
+     * @param other
+     */
+    public connectTo(other: Spans): Spans;
+
     /**
      * Returns the instantaneous start points of the these spans.
      */

merlin-server/src/test/java/gov/nasa/jpl/aerie/merlin/server/services/ConstraintsDSLCompilationServiceTests.java

@@ -36,6 +36,7 @@
 import gov.nasa.jpl.aerie.constraints.tree.ShiftBy;
 import gov.nasa.jpl.aerie.constraints.tree.ShiftEdges;
 import gov.nasa.jpl.aerie.constraints.tree.ShorterThan;
+import gov.nasa.jpl.aerie.constraints.tree.SpansConnectTo;
 import gov.nasa.jpl.aerie.constraints.tree.SpansFromWindows;
 import gov.nasa.jpl.aerie.constraints.tree.SpansSelectWhenTrue;
 import gov.nasa.jpl.aerie.constraints.tree.Split;
@@ -1378,4 +1379,25 @@ export default() => {
         )
     );
   }
+  @Test
+  void testSpansConnectTo() {
+    checkSuccessfulCompilation(
+        """
+          export default () => {
+            return Windows.Value(true).spans().connectTo(
+              Windows.Value(false).spans()
+            ).windows();
+          }
+        """,
+        new ViolationsOfWindows(
+            new WindowsFromSpans(
+                new SpansConnectTo(
+                    new SpansFromWindows(new WindowsValue(true)),
+                    new SpansFromWindows(new WindowsValue(false))
+                )
+            )
+        )
+    );
+  }
+
 }