Parse call with no effects and no args

1 files changed, 42 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/testing/MatcherBuilder.java b/src/test/java/org/shedlang/compiler/testing/MatcherBuilder.java
new file mode 100644
index 00000000..6736659f
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/testing/MatcherBuilder.java
@@ -0,0 +1,42 @@
+package org.shedlang.compiler.testing;
+
+import org.pcollections.Empty;
+import org.pcollections.PVector;
+import org.zwobble.precisely.MatchResult;
+import org.zwobble.precisely.Matcher;
+import org.zwobble.precisely.TextTree;
+
+import static org.zwobble.precisely.Matchers.instanceOf;
+
+public abstract class MatcherBuilder<T, U, This> implements Matcher<T> {
+    private final PVector<Matcher<? super U>> submatchers;
+
+    public MatcherBuilder() {
+        this(Empty.vector());
+    }
+
+    public MatcherBuilder(PVector<Matcher<? super U>> submatchers) {
+        this.submatchers = submatchers;
+    }
+
+    @Override
+    public MatchResult match(T actual) {
+        return toMatcher().match(actual);
+    }
+
+    @Override
+    public TextTree describe() {
+        return toMatcher().describe();
+    }
+
+    protected abstract Class<U> expectedType();
+    protected abstract This create(PVector<Matcher<? super U>> submatchers);
+
+    protected This with(Matcher<? super U> submatcher) {
+        return create(submatchers.plus(submatcher));
+    }
+
+    private Matcher<T> toMatcher() {
+        return instanceOf(expectedType(), submatchers);
+    }
+}