diff --git a/src/libslic3r/PlaceholderParser.hpp b/src/libslic3r/PlaceholderParser.hpp
index 8f4949b9b7..ae6ef8f02c 100644
--- a/src/libslic3r/PlaceholderParser.hpp
+++ b/src/libslic3r/PlaceholderParser.hpp
@@ -51,7 +51,7 @@ public:
 
     // Fill in the template using a macro processing language.
     // Throws Slic3r::PlaceholderParserError on syntax or runtime error.
-    std::string process(const std::string &templ, unsigned int current_extruder_id, const DynamicConfig *config_override = nullptr, ContextData *context = nullptr) const;
+    std::string process(const std::string &templ, unsigned int current_extruder_id = 0, const DynamicConfig *config_override = nullptr, ContextData *context = nullptr) const;
     
     // Evaluate a boolean expression using the full expressive power of the PlaceholderParser boolean expression syntax.
     // Throws Slic3r::PlaceholderParserError on syntax or runtime error.