diff --git a/conandata.yml b/conandata.yml
index 708b253..d6a1e88 100644
--- a/conandata.yml
+++ b/conandata.yml
@@ -1 +1 @@
-version: "1.0.0"
\ No newline at end of file
+version: "1.1.0"
diff --git a/include/cura-formulae-engine/ast/ast.h b/include/cura-formulae-engine/ast/ast.h
index 47ab271..64735a1 100644
--- a/include/cura-formulae-engine/ast/ast.h
+++ b/include/cura-formulae-engine/ast/ast.h
@@ -1,12 +1,12 @@
 #pragma once
 
-#include "cura-formulae-engine/eval.h"
-
-#include <zeus/expected.hpp>
-
 #include <functional>
 #include <string>
+#include <unordered_map>
 #include <unordered_set>
+#include <zeus/expected.hpp>
+
+#include "cura-formulae-engine/eval.h"
 
 namespace CuraFormulaeEngine::eval
 {
@@ -36,10 +36,13 @@ class EnvironmentMap : public Environment
 {
 private:
     std::unordered_map<std::string, eval::Value> environment_ = {};
-public:
 
+public:
     EnvironmentMap() = default;
-    explicit EnvironmentMap(const std::unordered_map<std::string, eval::Value>& map) : environment_(map) {}
+    explicit EnvironmentMap(const std::unordered_map<std::string, eval::Value>& map)
+        : environment_(map)
+    {
+    }
     ~EnvironmentMap() override = default;
 
     [[nodiscard]] std::optional<eval::Value> get(const std::string& key) const noexcept override;
@@ -52,31 +55,58 @@ class EnvironmentMap : public Environment
 
     void set(const std::string& key, const eval::Value& value) noexcept;
 
-    [[nodiscard]] EnvironmentMap clone() const noexcept;
+    void add(const std::unordered_map<std::string, eval::Value>& values);
 
+    [[nodiscard]] EnvironmentMap clone() const noexcept;
 };
 
-class LocalEnvironment : public Environment
+class ChainableEnvironment : public Environment
 {
+private:
+    const Environment* shadow_environment_{ nullptr };
+
 public:
+    explicit ChainableEnvironment(const Environment* shadow_environment = nullptr)
+        : shadow_environment_(shadow_environment)
+    {
+    }
+    ~ChainableEnvironment() override = default;
 
-    LocalEnvironment() = default;
-    explicit LocalEnvironment(const Environment* shadow_environment_)
-        : shadow_environment_(shadow_environment_)
+    [[nodiscard]] std::optional<eval::Value> get(const std::string& key) const noexcept override final;
+
+    [[nodiscard]] bool has(const std::string& key) const noexcept override final;
+
+    [[nodiscard]] std::unordered_map<std::string, eval::Value> getAll() const noexcept override final;
+
+protected:
+    [[nodiscard]] virtual std::optional<eval::Value> getImpl(const std::string& key) const noexcept = 0;
+
+    [[nodiscard]] virtual bool hasImpl(const std::string& key) const noexcept = 0;
+
+    [[nodiscard]] virtual std::unordered_map<std::string, eval::Value> getAllImpl() const noexcept = 0;
+};
+
+class LocalEnvironment : public ChainableEnvironment
+{
+private:
+    EnvironmentMap local_environment_;
+
+public:
+    explicit LocalEnvironment(const Environment* shadow_environment = nullptr)
+        : ChainableEnvironment(shadow_environment)
     {
     }
     ~LocalEnvironment() override = default;
 
-    EnvironmentMap local_environment_ = {};
-    const Environment* shadow_environment_;
-
-    [[nodiscard]] std::optional<eval::Value> get(const std::string& key) const noexcept override;
+    [[nodiscard]] std::optional<eval::Value> getImpl(const std::string& key) const noexcept override;
 
-    [[nodiscard]] bool has(const std::string& key) const noexcept override;
+    [[nodiscard]] bool hasImpl(const std::string& key) const noexcept override;
 
-    [[nodiscard]] std::unordered_map<std::string, eval::Value> getAll() const noexcept override;
+    [[nodiscard]] std::unordered_map<std::string, eval::Value> getAllImpl() const noexcept override;
 
     void set(const std::string& key, const eval::Value& value);
+
+    void add(const std::unordered_map<std::string, eval::Value>& values);
 };
 
 } // namespace CuraFormulaeEngine::env
@@ -123,7 +153,8 @@ struct Expr
     [[nodiscard]] virtual bool deepEq(const Expr& other) const = 0;
 
     /**
-     * @brief Traverses the expression tree and applies the visitor function to each node.
+     * @brief Traverses the expression tree and applies the visitor function to
+     * each node.
      *
      * @param visitor The visitor function to apply to each node.
      */
diff --git a/src/ast/ast.cpp b/src/ast/ast.cpp
index 9d1b1bc..9b775e2 100644
--- a/src/ast/ast.cpp
+++ b/src/ast/ast.cpp
@@ -5,11 +5,12 @@ namespace CuraFormulaeEngine::env
 
 std::optional<eval::Value> EnvironmentMap::get(const std::string& key) const noexcept
 {
-    if (!has(key))
+    auto iterator = environment_.find(key);
+    if (iterator == environment_.end())
     {
         return std::nullopt;
     }
-    return environment_.at(key);
+    return iterator->second;
 }
 
 bool EnvironmentMap::has(const std::string& key) const noexcept
@@ -32,44 +33,67 @@ void EnvironmentMap::set(const std::string& key, const eval::Value& value) noexc
     environment_.insert_or_assign(key, value);
 }
 
+void EnvironmentMap::add(const std::unordered_map<std::string, eval::Value>& values)
+{
+    environment_.insert(values.begin(), values.end());
+}
+
 EnvironmentMap EnvironmentMap::clone() const noexcept
 {
-    return EnvironmentMap{environment_};
+    return EnvironmentMap{ environment_ };
 }
 
-std::optional<eval::Value> LocalEnvironment::get(const std::string& key) const noexcept
+std::optional<eval::Value> LocalEnvironment::getImpl(const std::string& key) const noexcept
 {
-    if (local_environment_.has(key))
-    {
-        return local_environment_.get(key);
-    }
-    if (shadow_environment_ && shadow_environment_->has(key))
+    return local_environment_.get(key);
+}
+
+bool LocalEnvironment::hasImpl(const std::string& key) const noexcept
+{
+    return local_environment_.has(key);
+}
+
+std::unordered_map<std::string, eval::Value> LocalEnvironment::getAllImpl() const noexcept
+{
+    return local_environment_.getAll();
+}
+
+void LocalEnvironment::set(const std::string& key, const eval::Value& value)
+{
+    local_environment_.set(key, value);
+}
+
+void LocalEnvironment::add(const std::unordered_map<std::string, eval::Value>& values)
+{
+    local_environment_.add(values);
+}
+
+std::optional<eval::Value> ChainableEnvironment::get(const std::string& key) const noexcept
+{
+    std::optional<eval::Value> value = getImpl(key);
+    if (! value.has_value() && shadow_environment_)
     {
-        return shadow_environment_->get(key);
+        value = shadow_environment_->get(key);
     }
-    return std::nullopt;
+    return value;
 }
 
-bool LocalEnvironment::has(const std::string& key) const noexcept
+bool ChainableEnvironment::has(const std::string& key) const noexcept
 {
-    return local_environment_.has(key) || (shadow_environment_ && shadow_environment_->has(key));
+    return hasImpl(key) || (shadow_environment_ && shadow_environment_->has(key));
 }
 
-std::unordered_map<std::string, eval::Value> LocalEnvironment::getAll() const noexcept
+std::unordered_map<std::string, eval::Value> ChainableEnvironment::getAll() const noexcept
 {
     std::unordered_map<std::string, eval::Value> all;
-    if (shadow_environment_) {
+    if (shadow_environment_)
+    {
         all = shadow_environment_->getAll();
     }
 
-    auto scoped = local_environment_.getAll();
+    auto scoped = getAllImpl();
     all.insert(scoped.begin(), scoped.end());
     return all;
 }
 
-void LocalEnvironment::set(const std::string& key, const eval::Value& value)
-{
-    local_environment_.set(key, value);
-}
-
-} // namespace CuraFormulaeEngine::env
\ No newline at end of file
+} // namespace CuraFormulaeEngine::env