From d88f6a05f9ede852009ca9637e029d96a1509ff5 Mon Sep 17 00:00:00 2001
From: Riccardo Azzolini <riccardo4096@gmail.com>
Date: Fri, 5 Oct 2018 20:01:15 +0200
Subject: [PATCH] Define the Pattern interface and its core methods

---
 .../warppi/math/rules/dsl/Pattern.java        | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 core/src/main/java/it/cavallium/warppi/math/rules/dsl/Pattern.java

diff --git a/core/src/main/java/it/cavallium/warppi/math/rules/dsl/Pattern.java b/core/src/main/java/it/cavallium/warppi/math/rules/dsl/Pattern.java
new file mode 100644
index 00000000..3e26439b
--- /dev/null
+++ b/core/src/main/java/it/cavallium/warppi/math/rules/dsl/Pattern.java
@@ -0,0 +1,28 @@
+package it.cavallium.warppi.math.rules.dsl;
+
+import it.cavallium.warppi.math.Function;
+
+import java.util.Map;
+import java.util.Optional;
+
+/**
+ * Recognizes and generates functions of some specific shape.
+ */
+public interface Pattern {
+    /**
+     * Tries to match this pattern against a function and capture sub-functions.
+     *
+     * @param function The function to test the pattern against.
+     * @return The captured sub-functions, or an empty <code>Optional</code> if
+     *         the pattern doesn't match.
+     */
+    Optional<Map<String, Function>> match(Function function);
+
+    /**
+     * Creates a new function by filling in sub-functions within this pattern.
+     *
+     * @param subFunctions A map of named sub-functions to be inserted into this pattern.
+     * @return The resulting function.
+     */
+    Function replace(Map<String, Function> subFunctions);
+}