From 2d5c3288134f19088941c980e852521e9838db56 Mon Sep 17 00:00:00 2001
From: Ben Culkin <scorpress@gmail.com>
Date: Sat, 24 Sep 2022 12:35:20 -0400
Subject: Various changes

---
 src/main/java/bjc/funcdata/CList.java              | 54 ++++++++++++++++++++++
 src/main/java/bjc/funcdata/CListLike.java          | 13 ++++++
 src/main/java/bjc/funcdata/CListStructure.java     | 38 +++++++++++++++
 .../bjc/funcdata/bst/TreeLinearizationMethod.java  |  2 +-
 src/main/java/bjc/funcdata/theory/Category.java    | 28 +++++++++++
 5 files changed, 134 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/bjc/funcdata/CList.java
 create mode 100644 src/main/java/bjc/funcdata/CListLike.java
 create mode 100644 src/main/java/bjc/funcdata/CListStructure.java
 create mode 100644 src/main/java/bjc/funcdata/theory/Category.java

(limited to 'src/main/java/bjc/funcdata')

diff --git a/src/main/java/bjc/funcdata/CList.java b/src/main/java/bjc/funcdata/CList.java
new file mode 100644
index 0000000..b9ee10e
--- /dev/null
+++ b/src/main/java/bjc/funcdata/CList.java
@@ -0,0 +1,54 @@
+package bjc.funcdata;
+
+import java.util.function.UnaryOperator;
+
+import bjc.data.Either;
+import bjc.data.Pair;
+import bjc.functypes.Unit;
+
+public class CList<T> implements CListLike<T> {
+	private Either<Unit, Pair<T, CList<T>>> data;
+	
+	private CList() {
+		data = Either.left(Unit.UNIT);
+	}
+	
+	private CList(T data, CList<T> rest) {
+		this.data = Either.right(Pair.pair(data, rest));
+	}
+	
+	@Override
+	public boolean isEmpty() {
+		return data.isLeft();
+	}
+	
+	@Override
+	public T head() {
+		return data.forceRight().getLeft();
+	}
+	
+	@Override
+	public CList<T> tail() {
+		return data.forceRight().getRight();
+	}
+	
+	@Override
+	public CList<T> prefix(T val) {
+		return new CList<>(val, this);
+	}
+	
+	public static <T> UnaryOperator<CList<T>> prefixing(T val) {
+		return (lst) -> lst.prefix(val);
+	}
+	
+	public static <T> CList<T> empty() {
+		return new CList<>();
+	}
+	public static <T> CList<T> of(T... vals) {
+		CList<T> ret = empty();
+		for (int i = vals.length - 1; i >= 0; i-- ) {
+			ret = ret.prefix(vals[i]);
+		}
+		return ret;
+	}
+}
diff --git a/src/main/java/bjc/funcdata/CListLike.java b/src/main/java/bjc/funcdata/CListLike.java
new file mode 100644
index 0000000..ba17456
--- /dev/null
+++ b/src/main/java/bjc/funcdata/CListLike.java
@@ -0,0 +1,13 @@
+package bjc.funcdata;
+
+public interface CListLike<T> {
+
+	boolean isEmpty();
+
+	T head();
+
+	CListLike<T> tail();
+
+	CListLike<T> prefix(T val);
+
+}
\ No newline at end of file
diff --git a/src/main/java/bjc/funcdata/CListStructure.java b/src/main/java/bjc/funcdata/CListStructure.java
new file mode 100644
index 0000000..1809273
--- /dev/null
+++ b/src/main/java/bjc/funcdata/CListStructure.java
@@ -0,0 +1,38 @@
+package bjc.funcdata;
+
+import bjc.data.Either;
+
+// pretty sure we want to implement CListLike, but not obvious how to implement
+public class CListStructure<T> implements CListLike<Either<T, CListLike<T>>> {
+	private Either<T, CList<CListStructure<T>>> data;
+
+	public boolean isAtomic() {
+		return data.isLeft();
+	}
+
+	@Override
+	public boolean isEmpty() {
+		return true;
+	}
+
+	@Override
+	public Either<T, CListLike<T>> head() {
+		if (isAtomic()) return data.newRight();
+		// ... Beats me
+		return null;
+	}
+
+	@Override
+	public CListLike<Either<T, CListLike<T>>> tail() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public CListLike<Either<T, CListLike<T>>> prefix(Either<T, CListLike<T>> val) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+	
+	// There are almost certainly other methods we want here, just not sure what
+}
diff --git a/src/main/java/bjc/funcdata/bst/TreeLinearizationMethod.java b/src/main/java/bjc/funcdata/bst/TreeLinearizationMethod.java
index 65c013b..666834f 100644
--- a/src/main/java/bjc/funcdata/bst/TreeLinearizationMethod.java
+++ b/src/main/java/bjc/funcdata/bst/TreeLinearizationMethod.java
@@ -17,7 +17,7 @@ public enum TreeLinearizationMethod {
 	 */
 	POSTORDER,
 	/**
-	 * Visit the tree part itself, then the left side of tthis tree part and then
+	 * Visit the tree part itself, then the left side of this tree part and then
 	 * the right part.
 	 */
 	PREORDER
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
-- 
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