Various changes

1 files changed, 28 insertions, 0 deletions

diff --git a/src/main/java/bjc/funcdata/theory/Category.java b/src/main/java/bjc/funcdata/theory/Category.java
new file mode 100644
index 0000000..730465d
--- /dev/null
+++ b/src/main/java/bjc/funcdata/theory/Category.java
@@ -0,0 +1,28 @@
+package bjc.funcdata.theory;
+
+import java.util.Set;
+import java.util.function.Function;
+
+import bjc.data.Pair;
+import bjc.esodata.PairMap;
+
+// NOTE: haskell uses Category cat: ... where the parameter is the arrow type
+public interface Category<Element, Arrow> {	
+	Arrow identity(Element elem);
+	Arrow compose(Arrow left, Arrow right);
+}
+// Java objects would form a category as Category<Class<?>, Function<?, ?>>
+
+class FuncCategory implements Category<Class<?>, Function<?, ?>> {
+	@Override
+	public Function<?, ?> identity(Class<?> elem) {
+		return (vl) -> vl;
+	}
+
+	@Override
+	public Function<?, ?> compose(Function<?, ?> left, Function<?, ?> right) {
+		// right.compose((Function<? super V, ?>) left);
+		return null;
+	}
+	
+}
\ No newline at end of file