Add ExpressionFormatter which translates an smtutil::Expression into a Solidity-like expression string

libsolidity/formal/ExpressionFormatter.h

@@ -0,0 +1,41 @@
+/*
+	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/>.
+*/
+// SPDX-License-Identifier: GPL-3.0
+
+#pragma once
+
+/**
+ * Formats SMT expressions into Solidity-like strings.
+ */
+
+#include <libsolidity/formal/Predicate.h>
+
+#include <map>
+#include <string>
+
+namespace solidity::frontend::smt
+{
+
+/// @returns another smtutil::Expressions where every term in _from
+/// may be replaced if it is in the substitution map _subst.
+smtutil::Expression substitute(smtutil::Expression _from, std::map<std::string, std::string> const& _subst);
+
+/// @returns a Solidity-like expression string built from _expr.
+/// This is done at best-effort and is not guaranteed to always create a perfect Solidity expression string.
+std::string toSolidityStr(smtutil::Expression const& _expr);
+
+}