diff --git a/src/rime/config/config_compiler.cc b/src/rime/config/config_compiler.cc
index 6e8b23091..376cfb475 100644
--- a/src/rime/config/config_compiler.cc
+++ b/src/rime/config/config_compiler.cc
@@ -2,100 +2,12 @@
 #include <rime/common.h>
 #include <rime/resource.h>
 #include <rime/config/config_compiler.h>
+#include <rime/config/config_compiler_impl.h>
 #include <rime/config/config_data.h>
 #include <rime/config/config_types.h>
 
 namespace rime {
 
-enum DependencyPriority {
-  kPendingChild = 0,
-  kInclude = 1,
-  kPatch = 2,
-};
-
-struct Dependency {
-  an<ConfigItemRef> target;
-
-  virtual DependencyPriority priority() const = 0;
-  bool blocking() const {
-    return priority() > kPendingChild;
-  }
-  virtual string repr() const = 0;
-  virtual bool Resolve(ConfigCompiler* compiler) = 0;
-};
-
-template <class StreamT>
-StreamT& operator<< (StreamT& stream, const Dependency& dep) {
-  return stream << dep.repr();
-}
-
-struct PendingChild : Dependency {
-  string child_path;
-  an<ConfigItemRef> child_ref;
-
-  PendingChild(const string& path, const an<ConfigItemRef>& ref)
-      : child_path(path), child_ref(ref) {
-  }
-  DependencyPriority priority() const override {
-    return kPendingChild;
-  }
-  string repr() const override {
-    return "PendingChild(" + child_path + ")";
-  }
-  bool Resolve(ConfigCompiler* compiler) override;
-};
-
-string Reference::repr() const {
-  return resource_id + ":" + local_path + (optional ? " <optional>" : "");
-}
-
-template <class StreamT>
-StreamT& operator<< (StreamT& stream, const Reference& reference) {
-  return stream << reference.repr();
-}
-
-struct IncludeReference : Dependency {
-  IncludeReference(const Reference& r) : reference(r) {
-  }
-  DependencyPriority priority() const override {
-    return kInclude;
-  }
-  string repr() const override {
-    return "Include(" + reference.repr() + ")";
-  }
-  bool Resolve(ConfigCompiler* compiler) override;
-
-  Reference reference;
-};
-
-struct PatchReference : Dependency {
-  PatchReference(const Reference& r) : reference(r) {
-  }
-  DependencyPriority priority() const override {
-    return kPatch;
-  }
-  string repr() const override {
-    return "Patch(" + reference.repr() + ")";
-  }
-  bool Resolve(ConfigCompiler* compiler) override;
-
-  Reference reference;
-};
-
-struct PatchLiteral : Dependency {
-  an<ConfigMap> patch;
-
-  PatchLiteral(an<ConfigMap> map) : patch(map) {
-  }
-  DependencyPriority priority() const override {
-    return kPatch;
-  }
-  string repr() const override {
-    return "Patch(<literal>)";
-  }
-  bool Resolve(ConfigCompiler* compiler) override;
-};
-
 struct ConfigDependencyGraph {
   map<string, of<ConfigResource>> resources;
   vector<of<ConfigItemRef>> node_stack;
@@ -114,12 +26,18 @@ struct ConfigDependencyGraph {
     key_stack.pop_back();
   }
 
-  string current_resource_id() const {
-    return key_stack.empty() ? string()
-        : boost::trim_right_copy_if(key_stack.front(), boost::is_any_of(":"));
-  }
+  string current_resource_id() const;
 };
 
+string ConfigDependencyGraph::current_resource_id() const {
+  return key_stack.empty() ? string()
+      : boost::trim_right_copy_if(key_stack.front(), boost::is_any_of(":"));
+}
+
+string Reference::repr() const {
+  return resource_id + ":" + local_path + (optional ? " <optional>" : "");
+}
+
 bool PendingChild::Resolve(ConfigCompiler* compiler) {
   return compiler->ResolveDependencies(child_path);
 }
@@ -156,8 +74,7 @@ bool PatchReference::Resolve(ConfigCompiler* compiler) {
     return false;
   }
   PatchLiteral patch{As<ConfigMap>(item)};
-  patch.target = target;
-  return patch.Resolve(compiler);
+  return patch.TargetedAt(target).Resolve(compiler);
 }
 
 static bool AppendToString(an<ConfigItemRef> target, an<ConfigValue> value) {
@@ -294,7 +211,7 @@ void ConfigDependencyGraph::Add(an<Dependency> dependency) {
              << node_stack.size();
   if (node_stack.empty()) return;
   const auto& target = node_stack.back();
-  dependency->target = target;
+  dependency->TargetedAt(target);
   auto target_path = ConfigData::JoinPath(key_stack);
   auto& target_deps = deps[target_path];
   bool target_was_pending = !target_deps.empty();
@@ -353,6 +270,10 @@ void ConfigCompiler::AddDependency(an<Dependency> dependency) {
   graph_->Add(dependency);
 }
 
+void ConfigCompiler::Push(an<ConfigResource> resource) {
+  graph_->Push(resource, resource->resource_id + ":");
+}
+
 void ConfigCompiler::Push(an<ConfigList> config_list, size_t index) {
   graph_->Push(
       New<ConfigListEntryRef>(nullptr, config_list, index),
@@ -378,10 +299,10 @@ an<ConfigResource> ConfigCompiler::Compile(const string& file_name) {
   auto resource_id = resource_resolver_->ToResourceId(file_name);
   auto resource = New<ConfigResource>(resource_id, New<ConfigData>());
   graph_->resources[resource_id] = resource;
-  graph_->Push(resource, resource_id + ":");
+  Push(resource);
   resource->loaded = resource->data->LoadFromFile(
       resource_resolver_->ResolvePath(resource_id).string(), this);
-  graph_->Pop();
+  Pop();
   return resource;
 }
 
@@ -462,6 +383,11 @@ bool ConfigCompiler::resolved(const string& full_path) const {
   return found == graph_->deps.end() || found->second.empty();
 }
 
+vector<of<Dependency>> ConfigCompiler::GetDependencies(const string& path) {
+  auto found = graph_->deps.find(path);
+  return found == graph_->deps.end() ? vector<of<Dependency>>() : found->second;
+}
+
 static an<ConfigItem> ResolveReference(ConfigCompiler* compiler,
                                        const Reference& reference) {
   auto resource = compiler->GetCompiledResource(reference.resource_id);
diff --git a/src/rime/config/config_compiler.h b/src/rime/config/config_compiler.h
index 16704d49f..2975d2fcb 100644
--- a/src/rime/config/config_compiler.h
+++ b/src/rime/config/config_compiler.h
@@ -51,6 +51,7 @@ class ConfigCompiler {
 
   Reference CreateReference(const string& qualified_path);
   void AddDependency(an<Dependency> dependency);
+  void Push(an<ConfigResource> resource);
   void Push(an<ConfigList> config_list, size_t index);
   void Push(an<ConfigMap> config_map, const string& key);
   bool Parse(const string& key, const an<ConfigItem>& item);
@@ -63,6 +64,7 @@ class ConfigCompiler {
   bool blocking(const string& full_path) const;
   bool pending(const string& full_path) const;
   bool resolved(const string& full_path) const;
+  vector<of<Dependency>> GetDependencies(const string& path);
   bool ResolveDependencies(const string& path);
 
  private:
diff --git a/src/rime/config/config_compiler_impl.h b/src/rime/config/config_compiler_impl.h
new file mode 100644
index 000000000..cde33a7bd
--- /dev/null
+++ b/src/rime/config/config_compiler_impl.h
@@ -0,0 +1,100 @@
+//
+// Copyright RIME Developers
+// Distributed under the BSD License
+//
+#ifndef RIME_CONFIG_COMPILER_IMPL_H_
+#define RIME_CONFIG_COMPILER_IMPL_H_
+
+#include <rime/common.h>
+#include <rime/config/config_compiler.h>
+#include <rime/config/config_types.h>
+
+namespace rime {
+
+enum DependencyPriority {
+  kPendingChild = 0,
+  kInclude = 1,
+  kPatch = 2,
+};
+
+struct Dependency {
+  an<ConfigItemRef> target;
+
+  virtual DependencyPriority priority() const = 0;
+  bool blocking() const {
+    return priority() > kPendingChild;
+  }
+  virtual string repr() const = 0;
+  Dependency& TargetedAt(an<ConfigItemRef> target) {
+    this->target = target;
+    return *this;
+  }
+  virtual bool Resolve(ConfigCompiler* compiler) = 0;
+};
+
+template <class StreamT, class RepresentableT>
+StreamT& operator<< (StreamT& stream, const RepresentableT& representable) {
+  return stream << representable.repr();
+}
+
+struct PendingChild : Dependency {
+  string child_path;
+  an<ConfigItemRef> child_ref;
+
+  PendingChild(const string& path, const an<ConfigItemRef>& ref)
+      : child_path(path), child_ref(ref) {
+  }
+  DependencyPriority priority() const override {
+    return kPendingChild;
+  }
+  string repr() const override {
+    return "PendingChild(" + child_path + ")";
+  }
+  bool Resolve(ConfigCompiler* compiler) override;
+};
+
+struct IncludeReference : Dependency {
+  Reference reference;
+
+  IncludeReference(const Reference& r) : reference(r) {
+  }
+  DependencyPriority priority() const override {
+    return kInclude;
+  }
+  string repr() const override {
+    return "Include(" + reference.repr() + ")";
+  }
+  bool Resolve(ConfigCompiler* compiler) override;
+};
+
+struct PatchReference : Dependency {
+  Reference reference;
+
+  PatchReference(const Reference& r) : reference(r) {
+  }
+  DependencyPriority priority() const override {
+    return kPatch;
+  }
+  string repr() const override {
+    return "Patch(" + reference.repr() + ")";
+  }
+  bool Resolve(ConfigCompiler* compiler) override;
+};
+
+struct PatchLiteral : Dependency {
+  an<ConfigMap> patch;
+
+  PatchLiteral(an<ConfigMap> map) : patch(map) {
+  }
+  DependencyPriority priority() const override {
+    return kPatch;
+  }
+  string repr() const override {
+    return "Patch(<literal>)";
+  }
+  bool Resolve(ConfigCompiler* compiler) override;
+};
+
+}  // namespace rime
+
+#endif  // RIME_CONFIG_COMPILER_IMPL_H_