inference: deep nested session based on existing initial substitution (IDEA-167713)

2026-08-26 00:11:26 +07:00 · 2017-02-10 10:04:15 +01:00
parent a3e78bee41
commit e88322304e
3 changed files with 67 additions and 20 deletions
@@ -0,0 +1,39 @@
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+interface DuallyParametric<A0, B0> {
+  <R> R match(Function<? super A0, ? extends R> aFn, Function<? super B0, ? extends R> bFn);
+  static <Aa, Ba> DuallyParametric<Aa, Ba> a(Aa a) {
+    return null;
+  }
+
+  <Ab, Bb> DuallyParametric<Ab, Bb> b(Bb b);
+
+  <Al, Bl> Bl foldLeft(BiFunction<? super Bl, ? super Al, ? extends Bl> fn, Bl b, Iterable<Al> as);
+
+  default <A, B> DuallyParametric<A, B> merge(DuallyParametric<A, B> first,
+                                             BiFunction<? super A, ? super A, ? extends A> aFn,
+                                             BiFunction<? super B, ? super B, ? extends B> bFn,
+                                             Iterable<DuallyParametric<A, B>> others) {
+    return foldLeft((x, y) -> x.match(a1 -> y.match(a2 -> a(aFn.apply(a1, a2)), b -> a(a1)),
+                                      b1 -> y.match(DuallyParametric::a, b2 -> b(bFn.apply(b1, b2)))),
+                    first,
+                    others);
+  }
+}
+
+interface DuallyParametric1<A> {
+  default <R> R match(Function<A, R> aFn) {
+    return null;
+  }
+
+  static <Ba> DuallyParametric1<Ba> a() {
+    return null;
+  }
+
+  <Bl> void foldLeft(Function<Bl, Bl> fn, Bl b);
+
+  default void merge() {
+    foldLeft((x) -> x.match(a1 -> match(a2 -> a())), this);
+  }
+}