diff --git a/CMakeLists.txt b/CMakeLists.txt
index f056e7e..e8c27b0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.25)
-project(blt-gp VERSION 0.0.31)
+project(blt-gp VERSION 0.0.33)
 
 option(ENABLE_ADDRSAN "Enable the address sanitizer" OFF)
 option(ENABLE_UBSAN "Enable the ub sanitizer" OFF)
diff --git a/examples/main.cpp b/examples/main.cpp
index 212a53f..58cd793 100644
--- a/examples/main.cpp
+++ b/examples/main.cpp
@@ -345,12 +345,12 @@ int main_old()
     alloc.push(20.1230345);
     alloc.push(true);
     alloc.push(false);
-    alloc.push(std::string("SillyString"));
+    //alloc.push(std::string("SillyString"));
     alloc.push(&"SillyString");
     
     std::cout << std::endl;
     std::cout << *alloc.pop<decltype(&"SillString")>() << std::endl;
-    std::cout << alloc.pop<std::string>() << std::endl;
+    //std::cout << alloc.pop<std::string>() << std::endl;
     std::cout << alloc.pop<bool>() << std::endl;
     std::cout << alloc.pop<bool>() << std::endl;
     std::cout << alloc.pop<double>() << std::endl;
@@ -389,7 +389,7 @@ int main_old()
     alloc.push(50);
     alloc.push(550.3f);
     alloc.push(20.1230345);
-    alloc.push(std::string("SillyString"));
+    //alloc.push(std::string("SillyString"));
     alloc.push(33.22f);
     alloc.push(120);
     alloc.push(true);
diff --git a/include/blt/gp/fwdecl.h b/include/blt/gp/fwdecl.h
index 90a87a7..2981220 100644
--- a/include/blt/gp/fwdecl.h
+++ b/include/blt/gp/fwdecl.h
@@ -29,6 +29,10 @@ namespace blt::gp
     
     class type_system;
     
+    struct op_container_t;
+    
+    class evaluation_context;
+    
     class tree_t;
     
     class population_t;
diff --git a/include/blt/gp/generators.h b/include/blt/gp/generators.h
index 51dcfd1..68e8c4c 100644
--- a/include/blt/gp/generators.h
+++ b/include/blt/gp/generators.h
@@ -25,53 +25,89 @@
 namespace blt::gp
 {
     
+    struct generator_arguments
+    {
+        gp_program& program;
+        type_id root_type;
+        blt::size_t min_depth;
+        blt::size_t max_depth;
+    };
+    
+    struct initializer_arguments
+    {
+        gp_program& program;
+        type_id root_type;
+        blt::size_t size;
+        blt::size_t min_depth;
+        blt::size_t max_depth;
+        
+        [[nodiscard]] generator_arguments to_gen_args() const
+        {
+            return {program, root_type, min_depth, max_depth};
+        }
+    };
+    
     // base class for any kind of tree generator
     class tree_generator_t
     {
         public:
-            virtual tree_t generate(gp_program& program, blt::size_t min_depth, blt::size_t max_depth) = 0;
+            virtual tree_t generate(const generator_arguments& args) = 0;
     };
     
     class grow_generator_t : public tree_generator_t
     {
         public:
-            tree_t generate(gp_program& program, blt::size_t min_depth, blt::size_t max_depth) final;
+            tree_t generate(const generator_arguments& args) final;
     };
     
     class full_generator_t : public tree_generator_t
     {
         public:
-            tree_t generate(gp_program& program, blt::size_t min_depth, blt::size_t max_depth) final;
+            tree_t generate(const generator_arguments& args) final;
     };
     
     class population_initializer_t
     {
         public:
-            virtual population_t generate(gp_program& program, blt::size_t size, blt::size_t min_depth, blt::size_t max_depth) = 0;
+            virtual population_t generate(const initializer_arguments& args) = 0;
     };
     
-    class grow_initializer_t
+    class grow_initializer_t : public population_initializer_t
     {
         public:
-            population_t generate(gp_program& program, blt::size_t size, blt::size_t min_depth, blt::size_t max_depth) final;
+            population_t generate(const initializer_arguments& args) final;
+        
+        private:
+            grow_generator_t grow;
     };
     
-    class full_initializer_t
+    class full_initializer_t : public population_initializer_t
     {
         public:
-            population_t generate(gp_program& program, blt::size_t size, blt::size_t min_depth, blt::size_t max_depth) final;
+            population_t generate(const initializer_arguments& args) final;
+        
+        private:
+            full_generator_t full;
     };
     
-    class half_half_initializer_t
+    class half_half_initializer_t : public population_initializer_t
     {
         public:
-            population_t generate(gp_program& program, blt::size_t size, blt::size_t min_depth, blt::size_t max_depth) final;
+            population_t generate(const initializer_arguments& args) final;
+        
+        private:
+            grow_generator_t grow;
+            full_generator_t full;
     };
     
-    class ramped_half_initializer_t
+    class ramped_half_initializer_t : public population_initializer_t
     {
         public:
-            population_t generate(gp_program& program, blt::size_t size, blt::size_t min_depth, blt::size_t max_depth) final;
+            population_t generate(const initializer_arguments& args) final;
+        
+        private:
+            grow_generator_t grow;
+            full_generator_t full;
     };
     
 }
diff --git a/include/blt/gp/stack.h b/include/blt/gp/stack.h
index 5d9f96d..94b899d 100644
--- a/include/blt/gp/stack.h
+++ b/include/blt/gp/stack.h
@@ -41,8 +41,8 @@ namespace blt::gp
             template<typename T>
             void push(T&& value)
             {
-                static_assert(std::is_trivially_copyable_v<T> && "Type must be bitwise copyable!");
                 using NO_REF_T = std::remove_reference_t<T>;
+                static_assert(std::is_trivially_copyable_v<NO_REF_T> && "Type must be bitwise copyable!");
                 auto ptr = allocate_bytes<T>();
                 head->metadata.offset = static_cast<blt::u8*>(ptr) + aligned_size<T>();
                 new(ptr) NO_REF_T(std::forward<T>(value));
@@ -51,6 +51,7 @@ namespace blt::gp
             template<typename T>
             T pop()
             {
+                static_assert(std::is_trivially_copyable_v<std::remove_reference_t<T>> && "Type must be bitwise copyable!");
                 constexpr static auto TYPE_SIZE = aligned_size<T>();
                 if (head == nullptr)
                     throw std::runtime_error("Silly boi the stack is empty!");
diff --git a/include/blt/gp/tree.h b/include/blt/gp/tree.h
index ff53c9e..700eeeb 100644
--- a/include/blt/gp/tree.h
+++ b/include/blt/gp/tree.h
@@ -24,13 +24,34 @@
 #include <blt/gp/fwdecl.h>
 #include <blt/std/types.h>
 
+#include <utility>
+#include <stack>
+
 namespace blt::gp
 {
     
     struct op_container_t
     {
-        blt::gp::operator_id op_id;
+        op_container_t(detail::callable_t& func, u16 depth, bool isStatic, u16 argc, u8 argcContext):
+                func(func), depth(depth), is_static(isStatic), argc(argc), argc_context(argcContext)
+        {}
+        
+        detail::callable_t& func;
         blt::u16 depth;
+        bool is_static: 1;
+        blt::u16 argc: 15;
+        blt::u8 argc_context;
+    };
+    
+    class evaluation_context
+    {
+            friend class tree_t;
+        
+        private:
+            explicit evaluation_context(stack_allocator values): values(std::move(values))
+            {}
+            
+            blt::gp::stack_allocator values;
     };
     
     class tree_t
@@ -65,6 +86,36 @@ namespace blt::gp
                 valid = true;
                 return 0;
             }
+            
+            evaluation_context evaluate(void* context);
+            
+            /**
+             * Helper template for returning the result of the last evaluation
+             */
+            template<typename T>
+            T get_evaluation_value(evaluation_context& context)
+            {
+                return context.values.pop<T>();
+            }
+            
+            /**
+             * Helper template for returning the result of the last evaluation
+             */
+            template<typename T>
+            T& get_evaluation_ref(evaluation_context& context)
+            {
+                return context.values.from<T>(0);
+            }
+            
+            /**
+             * Helper template for returning the result of evalutation (this calls it)
+             */
+            template<typename T>
+            T get_evaluation_value(void* context)
+            {
+                auto results = evaluate(context);
+                return results.values.pop<T>();
+            }
         
         private:
             bool valid = false;
@@ -76,6 +127,10 @@ namespace blt::gp
     class population_t
     {
         public:
+            std::vector<tree_t>& getIndividuals()
+            {
+                return individuals;
+            }
         
         private:
             std::vector<tree_t> individuals;
diff --git a/src/generators.cpp b/src/generators.cpp
index c1e971b..59c5f87 100644
--- a/src/generators.cpp
+++ b/src/generators.cpp
@@ -21,6 +21,8 @@
 
 namespace blt::gp
 {
+    // TODO: change how the generators work, but keep how nice everything is within the C++ file. less headers!
+    // maybe have tree call the generate functions with out variables as the members of tree_t
     
     struct stack
     {
@@ -28,27 +30,27 @@ namespace blt::gp
         blt::size_t depth;
     };
     
-    inline std::stack<stack> get_initial_stack(gp_program& program)
+    inline std::stack<stack> get_initial_stack(gp_program& program, type_id root_type)
     {
         std::stack<stack> tree_generator;
-        
-        auto& system = program.get_typesystem();
-        // select a type which has a non-empty set of non-terminals
-        type base_type;
-        do
-        {
-            base_type = system.select_type(program.get_random());
-        } while (program.get_type_non_terminals(base_type.id()).empty());
-        
-        tree_generator.push(stack{program.select_non_terminal(base_type.id()), 1});
+//
+//        auto& system = program.get_typesystem();
+//        // select a type which has a non-empty set of non-terminals
+//        type base_type;
+//        do
+//        {
+//            base_type = system.select_type(program.get_random());
+//        } while (program.get_type_non_terminals(base_type.id()).empty());
+//
+        tree_generator.push(stack{program.select_non_terminal(root_type), 1});
         
         return tree_generator;
     }
     
     template<typename Func>
-    inline tree_t create_tree(Func&& perChild, gp_program& program)
+    inline tree_t create_tree(Func&& perChild, const generator_arguments& args)
     {
-        std::stack<stack> tree_generator = get_initial_stack(program);
+        std::stack<stack> tree_generator = get_initial_stack(args.program, args.root_type);
         blt::size_t max_depth = 0;
         tree_t tree;
         
@@ -57,18 +59,24 @@ namespace blt::gp
             auto top = tree_generator.top();
             tree_generator.pop();
             
-            tree.get_operations().push_back({top.id, static_cast<blt::u16>(top.depth)});
+            tree.get_operations().emplace_back(
+                args.program.get_operation(top.id),
+                static_cast<blt::u16>(top.depth),
+                args.program.is_static(top.id),
+                static_cast<blt::u16>(args.program.get_argc(top.id).argc),
+                static_cast<blt::u8>(args.program.get_argc(top.id).argc_context)
+            );
             max_depth = std::max(max_depth, top.depth);
             
-            if (program.is_static(top.id))
+            if (args.program.is_static(top.id))
             {
-                program.get_operation(top.id)(nullptr, tree.get_values());
+                args.program.get_operation(top.id)(nullptr, tree.get_values());
                 continue;
             }
             
-            for (const auto& child : program.get_argument_types(top.id))
+            for (const auto& child : args.program.get_argument_types(top.id))
             {
-                std::forward<Func>(perChild)(program, tree_generator, child, top.depth + 1);
+                std::forward<Func>(perChild)(args.program, tree_generator, child, top.depth + 1);
             }
         }
         
@@ -77,50 +85,96 @@ namespace blt::gp
         return tree;
     }
     
-    tree_t grow_generator_t::generate(gp_program& program, blt::size_t min_depth, blt::size_t max_depth)
+    tree_t grow_generator_t::generate(const generator_arguments& args)
     {
-        return create_tree([min_depth, max_depth](gp_program& program, std::stack<stack>& tree_generator, const type& type, blt::size_t new_depth) {
-            if (new_depth >= max_depth)
+        return create_tree([args](gp_program& program, std::stack<stack>& tree_generator, const type& type, blt::size_t new_depth) {
+            if (new_depth >= args.max_depth)
             {
                 tree_generator.push({program.select_terminal(type.id()), new_depth});
                 return;
             }
-            if (program.choice() || new_depth < min_depth)
+            if (program.choice() || new_depth < args.min_depth)
                 tree_generator.push({program.select_non_terminal(type.id()), new_depth});
             else
                 tree_generator.push({program.select_terminal(type.id()), new_depth});
-        }, program);
+        }, args);
     }
     
-    tree_t full_generator_t::generate(gp_program& program, blt::size_t, blt::size_t max_depth)
+    tree_t full_generator_t::generate(const generator_arguments& args)
     {
-        return create_tree([max_depth](gp_program& program, std::stack<stack>& tree_generator, const type& type, blt::size_t new_depth) {
-            if (new_depth >= max_depth)
+        return create_tree([args](gp_program& program, std::stack<stack>& tree_generator, const type& type, blt::size_t new_depth) {
+            if (new_depth >= args.max_depth)
             {
                 tree_generator.push({program.select_terminal(type.id()), new_depth});
                 return;
             }
             tree_generator.push({program.select_non_terminal(type.id()), new_depth});
-        }, program);
+        }, args);
     }
     
-    population_t grow_initializer_t::generate(gp_program& program, blt::size_t size, blt::size_t min_depth, blt::size_t max_depth)
+    population_t grow_initializer_t::generate(const initializer_arguments& args)
     {
-        return population_t();
+        population_t pop;
+        
+        for (auto i = 0ul; i < args.size; i++)
+            pop.getIndividuals().push_back(grow.generate(args.to_gen_args()));
+        
+        return pop;
     }
     
-    population_t full_initializer_t::generate(gp_program& program, blt::size_t size, blt::size_t min_depth, blt::size_t max_depth)
+    population_t full_initializer_t::generate(const initializer_arguments& args)
     {
-        return population_t();
+        population_t pop;
+        
+        for (auto i = 0ul; i < args.size; i++)
+            pop.getIndividuals().push_back(full.generate(args.to_gen_args()));
+        
+        return pop;
     }
     
-    population_t half_half_initializer_t::generate(gp_program& program, blt::size_t size, blt::size_t min_depth, blt::size_t max_depth)
+    population_t half_half_initializer_t::generate(const initializer_arguments& args)
     {
-        return population_t();
+        population_t pop;
+        
+        for (auto i = 0ul; i < args.size; i++)
+        {
+            if (args.program.choice())
+                pop.getIndividuals().push_back(full.generate(args.to_gen_args()));
+            else
+                pop.getIndividuals().push_back(grow.generate(args.to_gen_args()));
+        }
+        
+        return pop;
     }
     
-    population_t ramped_half_initializer_t::generate(gp_program& program, blt::size_t size, blt::size_t min_depth, blt::size_t max_depth)
+    population_t ramped_half_initializer_t::generate(const initializer_arguments& args)
     {
-        return population_t();
+        auto steps = args.max_depth - args.min_depth;
+        auto per_step = args.size / steps;
+        auto remainder = args.size % steps;
+        population_t pop;
+        
+        for (auto depth : blt::range(args.min_depth, args.max_depth))
+        {
+            for (auto i = 0ul; i < per_step; i++)
+            {
+                if (args.program.choice())
+                    pop.getIndividuals().push_back(full.generate({args.program, args.root_type, args.min_depth, depth}));
+                else
+                    pop.getIndividuals().push_back(grow.generate({args.program, args.root_type, args.min_depth, depth}));
+            }
+        }
+        
+        for (auto i = 0ul; i < remainder; i++)
+        {
+            if (args.program.choice())
+                pop.getIndividuals().push_back(full.generate(args.to_gen_args()));
+            else
+                pop.getIndividuals().push_back(grow.generate(args.to_gen_args()));
+        }
+        
+        blt_assert(pop.getIndividuals().size() == args.size);
+        
+        return pop;
     }
 }
\ No newline at end of file
diff --git a/src/tree.cpp b/src/tree.cpp
new file mode 100644
index 0000000..54b3408
--- /dev/null
+++ b/src/tree.cpp
@@ -0,0 +1,33 @@
+/*
+ *  <Short Description>
+ *  Copyright (C) 2024  Brett Terpstra
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <blt/gp/tree.h>
+
+namespace blt::gp
+{
+    evaluation_context tree_t::evaluate(void* context)
+    {
+        evaluation_context results {values};
+        
+        auto& value_stack = results.values;
+        std::stack<op_container_t> operations_stack;
+        
+        
+        
+        return results;
+    }
+}
\ No newline at end of file