[yul-phaser] Base class for fitness metrics

test/CMakeLists.txt

@@ -151,6 +151,7 @@ set(yul_phaser_sources
     # My current workaround is just to include its source files here but this introduces
     # unnecessary duplication. Create a library or find a way to reuse the list in both places.
     ../tools/yulPhaser/Chromosome.cpp
+    ../tools/yulPhaser/FitnessMetrics.cpp
     ../tools/yulPhaser/Population.cpp
     ../tools/yulPhaser/Program.cpp
     ../tools/yulPhaser/SimulationRNG.cpp

tools/CMakeLists.txt

@@ -17,6 +17,8 @@ add_executable(yul-phaser
 	yulPhaser/main.cpp
 	yulPhaser/Population.h
 	yulPhaser/Population.cpp
+	yulPhaser/FitnessMetrics.h
+	yulPhaser/FitnessMetrics.cpp
 	yulPhaser/Chromosome.h
 	yulPhaser/Chromosome.cpp
 	yulPhaser/Program.h

tools/yulPhaser/FitnessMetrics.cpp

@@ -0,0 +1,18 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <tools/yulPhaser/FitnessMetrics.h>

tools/yulPhaser/FitnessMetrics.h

@@ -0,0 +1,48 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * Contains an abstract base class representing a fitness metric and its concrete implementations.
+ */
+
+#pragma once
+
+#include <tools/yulPhaser/Chromosome.h>
+
+#include <cstddef>
+
+namespace solidity::phaser
+{
+
+/**
+ * Abstract base class for fitness metrics.
+ *
+ * The main feature is the @a evaluate() method that can tell how good a given chromosome is.
+ * The lower the value, the better the fitness is. The result should be deterministic and depend
+ * only on the chromosome and metric's state (which is constant).
+ */
+class FitnessMetric
+{
+public:
+	FitnessMetric() = default;
+	FitnessMetric(FitnessMetric const&) = delete;
+	FitnessMetric& operator=(FitnessMetric const&) = delete;
+	virtual ~FitnessMetric() = default;
+
+	virtual size_t evaluate(Chromosome const& _chromosome) const = 0;
+};
+
+}