[core] Remove stops-based *Function constructors

1 files changed, 40 insertions, 0 deletions

diff --git a/src/mbgl/style/function/convert.cpp b/src/mbgl/style/function/convert.cpp
new file mode 100644
index 0000000000..a3b19f287b
--- /dev/null
+++ b/src/mbgl/style/function/convert.cpp
@@ -0,0 +1,40 @@
+#include <mbgl/style/function/convert.hpp>
+
+namespace mbgl {
+namespace style {
+namespace expression {
+
+std::unique_ptr<Expression> Convert::fromIdentityFunction(const std::string& property, type::Type type) {
+    return type.match(
+        [&] (const type::StringType&) {
+            return makeGet(type::String, property);
+        },
+        [&] (const type::NumberType&) {
+            return makeGet(type::Number, property);
+        },
+        [&] (const type::BooleanType&) {
+            return makeGet(type::Boolean, property);
+        },
+        [&] (const type::ColorType&) {
+            std::vector<std::unique_ptr<Expression>> args;
+            args.push_back(makeGet(type::String, property));
+            return std::make_unique<Coercion>(type::Color, std::move(args));
+        },
+        [&] (const type::Array& arr) {
+            std::vector<std::unique_ptr<Expression>> getArgs;
+            getArgs.push_back(makeLiteral(property));
+            ParsingContext ctx;
+            ParseResult get = createCompoundExpression("get", std::move(getArgs), ctx);
+            assert(get);
+            assert(ctx.getErrors().size() == 0);
+            return std::make_unique<ArrayAssertion>(arr, std::move(*get));
+        },
+        [&] (const auto&) -> std::unique_ptr<Expression> {
+            return makeLiteral(Null);
+        }
+    );
+}
+
+} // namespace expression
+} // namespace style
+} // namespace mbgl