1 files changed, 23 insertions, 0 deletions
diff --git a/src/buildtool/build_engine/expression/function_map.hpp b/src/buildtool/build_engine/expression/function_map.hpp
new file mode 100644
index 00000000..967d5fe0
--- /dev/null
+++ b/src/buildtool/build_engine/expression/function_map.hpp
@@ -0,0 +1,23 @@
+#ifndef INCLUDED_SRC_BUILDTOOL_BUILD_ENGINE_EXPRESSION_FUNCTION_MAP_HPP
+#define INCLUDED_SRC_BUILDTOOL_BUILD_ENGINE_EXPRESSION_FUNCTION_MAP_HPP
+
+#include <functional>
+#include <string>
+
+#include "src/buildtool/build_engine/expression/linked_map.hpp"
+
+class ExpressionPtr;
+class Configuration;
+
+using SubExprEvaluator =
+    std::function<ExpressionPtr(ExpressionPtr const&, Configuration const&)>;
+
+using FunctionMap =
+    LinkedMap<std::string,
+              std::function<ExpressionPtr(SubExprEvaluator&&,
+                                          ExpressionPtr const&,
+                                          Configuration const&)>>;
+
+using FunctionMapPtr = FunctionMap::Ptr;
+
+#endif  // INCLUDED_SRC_BUILDTOOL_BUILD_ENGINE_EXPRESSION_FUNCTION_MAP_HPP