[core] Add number-format expression

3 files changed, 45 insertions, 1 deletions

diff --git a/include/mbgl/style/expression/expression.hpp b/include/mbgl/style/expression/expression.hpp
index 22ae57c2be..5f66fc6dc7 100644
--- a/include/mbgl/style/expression/expression.hpp
+++ b/include/mbgl/style/expression/expression.hpp
@@ -142,7 +142,8 @@ enum class Kind : int32_t {
     All,
     Comparison,
     FormatExpression,
-    FormatSectionOverride
+    FormatSectionOverride,
+    NumberFormat
 };
 
 class Expression {
diff --git a/include/mbgl/style/expression/number_format.hpp b/include/mbgl/style/expression/number_format.hpp
new file mode 100644
index 0000000000..9571c7d98a
--- /dev/null
+++ b/include/mbgl/style/expression/number_format.hpp
@@ -0,0 +1,40 @@
+#pragma once
+
+#include <mbgl/style/expression/expression.hpp>
+#include <mbgl/style/expression/parsing_context.hpp>
+
+namespace mbgl {
+namespace style {
+namespace expression {
+
+class NumberFormat final : public Expression {
+public:
+    NumberFormat(std::unique_ptr<Expression> number_,
+                 std::unique_ptr<Expression> locale_,
+                 std::unique_ptr<Expression> currency_,
+                 std::unique_ptr<Expression> minFractionDigits_,
+                 std::unique_ptr<Expression> maxFractionDigits_);
+
+    ~NumberFormat();
+
+    static ParseResult parse(const mbgl::style::conversion::Convertible& value, ParsingContext& ctx);
+
+    EvaluationResult evaluate(const EvaluationContext& params) const override;
+    void eachChild(const std::function<void(const Expression&)>& visit) const override;
+    bool operator==(const Expression& e) const override;
+    std::vector<optional<Value>> possibleOutputs() const override;
+
+    mbgl::Value serialize() const override;
+    std::string getOperator() const override { return "number-format"; }
+
+private:
+    std::unique_ptr<Expression> number;
+    std::unique_ptr<Expression> locale;
+    std::unique_ptr<Expression> currency;
+    std::unique_ptr<Expression> minFractionDigits;
+    std::unique_ptr<Expression> maxFractionDigits;
+};
+
+} // namespace expression
+} // namespace style
+} // namespace mbgl
diff --git a/include/mbgl/util/platform.hpp b/include/mbgl/util/platform.hpp
index 3544659740..2e11e5f186 100644
--- a/include/mbgl/util/platform.hpp
+++ b/include/mbgl/util/platform.hpp
@@ -16,6 +16,9 @@ std::string lowercase(const std::string &string);
 // Gets the name of the current thread.
 std::string getCurrentThreadName();
 
+std::string formatNumber(double number, const std::string& localeId, const std::string& currency,
+                         uint8_t minFractionDigits, uint8_t maxFractionDigits);
+
 // Set the name of the current thread, truncated at 15.
 void setCurrentThreadName(const std::string& name);