From 0b727108c8517be7fc2d03d5843aefd94cb789be Mon Sep 17 00:00:00 2001
From: Alexander Shalamov <alexander.shalamov@mapbox.com>
Date: Mon, 3 Feb 2020 12:32:16 +0200
Subject: [core] Add getSharedExpression to property expression

New method can be used for aggregating property expressions from
multiple properties(layers) into single match / case expression.
---
 include/mbgl/style/property_expression.hpp | 5 +++++
 src/mbgl/style/property_expression.cpp     | 4 ++++
 2 files changed, 9 insertions(+)

diff --git a/include/mbgl/style/property_expression.hpp b/include/mbgl/style/property_expression.hpp
index 7dcd818dde..7439ac9ca1 100644
--- a/include/mbgl/style/property_expression.hpp
+++ b/include/mbgl/style/property_expression.hpp
@@ -21,6 +21,11 @@ public:
     Range<float> getCoveringStops(const float, const float) const noexcept;
     const expression::Expression& getExpression() const noexcept;
 
+    // Can be used for aggregating property expressions from multiple
+    // properties(layers) into single match / case expression. Method may
+    // be removed if a better way of aggregation is found.
+    std::shared_ptr<const expression::Expression> getSharedExpression() const noexcept;
+
     bool useIntegerZoom = false;
 
 protected:
diff --git a/src/mbgl/style/property_expression.cpp b/src/mbgl/style/property_expression.cpp
index d531181e71..8d603e4b15 100644
--- a/src/mbgl/style/property_expression.cpp
+++ b/src/mbgl/style/property_expression.cpp
@@ -54,5 +54,9 @@ const expression::Expression& PropertyExpressionBase::getExpression() const noex
     return *expression;
 }
 
+std::shared_ptr<const expression::Expression> PropertyExpressionBase::getSharedExpression() const noexcept {
+    return expression;
+}
+
 } // namespace style
 } // namespace mbgl
-- 
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