diff --git a/include/basic_printers.hpp b/include/basic_printers.hpp
index 34321e4..e584761 100644
--- a/include/basic_printers.hpp
+++ b/include/basic_printers.hpp
@@ -42,9 +42,9 @@ public:
     print_spaces(indentation);
   }
 
-  void indent() { ++current_indentation_level_; }
+  void indent() { current_indentation_level_ += tab_width_; }
 
-  void deindent() { --current_indentation_level_; }
+  void deindent() { current_indentation_level_ -= tab_width_; }
 
   void tab() { print_spaces(tab_width_); }
 
@@ -64,7 +64,15 @@ public:
     return print_words_instead_of_symbols_;
   }
 
-  size_t get_current_position() { return current_position_; }
+  size_t get_current_position() const { return current_position_; }
+
+  size_t get_current_indentation_level() const {
+    return current_indentation_level_;
+  }
+
+  size_t set_current_indentation_level(size_t indentation_level) {
+    current_indentation_level_ = indentation_level;
+  }
 
 private:
   void end_line() {
diff --git a/include/doc_printers.hpp b/include/doc_printers.hpp
new file mode 100644
index 0000000..3ffbe04
--- /dev/null
+++ b/include/doc_printers.hpp
@@ -0,0 +1,10 @@
+#pragma once
+
+#include "basic_printers.hpp"
+#include "doc_nodes.hpp"
+
+namespace printers {
+
+void print_docs(const nodes::SymbolDocs &docs, Printer &printer);
+
+} // namespace printers
diff --git a/include/statement_nodes.hpp b/include/statement_nodes.hpp
index b0ef122..8078f93 100644
--- a/include/statement_nodes.hpp
+++ b/include/statement_nodes.hpp
@@ -72,7 +72,7 @@ public:
                      std::vector<std::optional<std::string>> &&annotations,
                      std::vector<Identifier> &&arguments,
                      std::vector<Modifier> &&reference_types,
-                     std::vector<std::optional<TypeProxy>> &&types,
+                     std::vector<TypeProxy> &&types,
                      std::vector<bool> &&optional_arguments,
                      std::vector<bool> &&result_arguments,
                      std::optional<ExpressionProxy> expression)
@@ -101,7 +101,7 @@ public:
 
   //
 
-  ModifierType get_modifier() { return modifier_; }
+  ModifierType get_modifier() const { return modifier_; }
 
   //
 
@@ -135,7 +135,7 @@ public:
 
   //
 
-  Modifier get_argument_reference_type(size_t id) {
+  Modifier get_argument_reference_type(size_t id) const {
     return reference_types_.at(id);
   }
 
@@ -143,19 +143,9 @@ public:
 
   size_t get_argument_types_size() const { return types_.size(); }
 
-  std::optional<Type *> get_argument_type(size_t id) {
-    if (types_.at(id).has_value()) {
-      return types_[id].value().get();
-    }
-    return std::nullopt;
-  }
+  Type *get_argument_type(size_t id) { return types_.at(id).get(); }
 
-  std::optional<const Type *> get_argument_type(size_t id) const {
-    if (types_.at(id).has_value()) {
-      return types_[id].value().get();
-    }
-    return std::nullopt;
-  }
+  const Type *get_argument_type(size_t id) const { return types_.at(id).get(); }
 
   //
 
@@ -191,7 +181,7 @@ private:
   std::vector<std::optional<std::string>> annotations_;
   std::vector<Identifier> arguments_;
   std::vector<Modifier> reference_types_;
-  std::vector<std::optional<TypeProxy>> types_;
+  std::vector<TypeProxy> types_;
   std::vector<bool> optional_arguments_;
   std::vector<bool> result_arguments_;
   std::optional<ExpressionProxy> expression_;
@@ -215,7 +205,7 @@ public:
 
   //
 
-  bool is_on_heap() { return is_on_heap_; }
+  bool is_on_heap() const { return is_on_heap_; }
 
   //
 
diff --git a/src/doc_printers.cpp b/src/doc_printers.cpp
new file mode 100644
index 0000000..3c0bada
--- /dev/null
+++ b/src/doc_printers.cpp
@@ -0,0 +1,14 @@
+#include "doc_printers.hpp"
+#include "utils.hpp"
+
+namespace printers {
+
+// TODO
+
+void print_docs(const nodes::SymbolDocs &docs, Printer &printer) {
+
+  error_handling::handle_general_error("Docs printing unimplemented yet");
+
+} // IN PROGRESS
+
+} // namespace printers
diff --git a/src/expression_printers.cpp b/src/expression_printers.cpp
index 10dd1d3..84b40e2 100644
--- a/src/expression_printers.cpp
+++ b/src/expression_printers.cpp
@@ -85,7 +85,6 @@ void print_case(const nodes::Match::Case &expression, Printer &printer) {
   print_expression(*expression.get_value(), printer);
 
   if (expression.get_condition().has_value()) {
-
     printer.print(printer.print_words_instead_of_symbols() ? " if " : " ?? ");
     print_expression(*expression.get_condition().value(), printer);
   }
@@ -101,16 +100,20 @@ void print_match(const nodes::Match &expression, printers::Printer &printer) {
 
   printer.space();
 
-  size_t indentation = printer.get_current_position();
+  size_t previous_indentation_level = printer.get_current_indentation_level();
+
+  printer.set_current_indentation_level(printer.current_position());
 
   for (size_t i = 0; i < expression.cases_size(); ++i) {
     print_case(*expression.get_case(i), printer);
 
     if (i + 1 < expression.cases_size()) {
-      printer.new_line(indentation);
+      printer.new_indent_line();
     }
   }
 
+  printer.set_current_indentation_level(previous_indentation_level);
+
 } // IN PROGRESS
 
 void print_condition(const nodes::Condition &expression,
diff --git a/src/statement_builders.cpp b/src/statement_builders.cpp
index 98e2850..d650d2f 100644
--- a/src/statement_builders.cpp
+++ b/src/statement_builders.cpp
@@ -236,7 +236,7 @@ build_function_definition(parser::ParseTree::Node parser_node,
 
   std::vector<std::optional<std::string>> type_annotations;
   std::vector<nodes::Modifier> type_reference_types;
-  std::vector<std::optional<nodes::TypeProxy>> types;
+  std::vector<nodes::TypeProxy> types;
 
   std::optional<parser::ParseTree::Node> expression_node;
 
@@ -277,7 +277,7 @@ build_function_definition(parser::ParseTree::Node parser_node,
                                  current_node.next_sibling().is_named() &&
                                  current_node.next_sibling().get_value() ==
                                      "!");
-      if (optional_arguments.back() | result_arguments.back()) {
+      if (optional_arguments.back() || result_arguments.back()) {
         at_least_one_argument_modifier_found = true;
       }
 
diff --git a/src/statement_printers.cpp b/src/statement_printers.cpp
index 890e97a..a51e2a1 100644
--- a/src/statement_printers.cpp
+++ b/src/statement_printers.cpp
@@ -1,7 +1,10 @@
 #include "statement_printers.hpp"
 
 #include "basic_printers.hpp"
+#include "doc_printers.hpp"
+#include "expression_nodes.hpp"
 #include "expression_printers.hpp"
+#include "type_printers.hpp"
 
 namespace printers {
 
@@ -39,11 +42,166 @@ void print_constraint(const nodes::Constraint &statement, Printer &printer) {
 void print_type_definition(const nodes::TypeDefinition &statement,
                            Printer &printer) {
   print_docs(*statement.get_docs(), printer); // TODO
+
+  if (statement.is_on_heap()) {
+    printer.print("^");
+  }
+
+  print_identifier(*statement.get_name(), printer);
+
+  for (size_t i = 0; i < statement.get_arguments_size(); ++i) {
+    printer.space();
+    print_identifier(*statement.get_argument(i), printer);
+  }
+
+  if (statement.get_type().has_value()) {
+    printer.print(" = ");
+
+    size_t previous_indentation_level = printer.get_current_indentation_level();
+
+    printer.set_current_indentation_level(printer.get_current_position());
+
+    print_variant_type(*statement.get_type().value(), printer);
+
+    printer.set_current_indentation_level(previous_indentation_level);
+  }
+
+  // TODO: same to typeclass, make separated function
+  if (statement.get_methods_size() > 0) {
+    printer.print(" {");
+    printer.indent();
+
+    for (size_t i = 0; i < statement.get_methods_size(); ++i) {
+      printer.new_indent_line();
+      print_function_definition(*statement.get_method(i), printer);
+      printer.new_indent_line();
+    }
+
+    printer.deindent();
+    printer.new_indent_line();
+    printer.print("} ");
+  } else {
+    printer.print(";");
+  }
+
 } // IN PROGRESS
 
 void print_function_definition(const nodes::FunctionDefinition &statement,
                                Printer &printer) {
   print_docs(*statement.get_docs(), printer); // TODO
+
+  for (size_t i = 0; i < statement.get_constraints_size(); ++i) {
+    print_constraint(*statement.get_constraint(i), printer);
+    printer.new_indent_line();
+  }
+
+  switch (statement.get_modifier()) {
+  case nodes::FunctionDefinition::STATIC:
+    break;
+  case nodes::FunctionDefinition::LET:
+    printer.print(printer.print_words_instead_of_symbols() ? "let " : "% ");
+    break;
+  case nodes::FunctionDefinition::VAR:
+    printer.print(printer.print_words_instead_of_symbols() ? "var " : "$ ");
+    break;
+  default: // remove ??
+    break;
+  }
+
+  print_identifier(*statement.get_name(), printer);
+
+  // TODO: same fragments with function type, maybe better make separated
+  // function
+  for (size_t i = 0; i < statement.get_arguments_size(); ++i) {
+    if (statement.get_argument_types_size() == 0) {
+      if (statement.get_argument_annotation(i).has_value()) {
+        print_annotation(*statement.get_argument_annotation(i).value(),
+                         printer);
+        printer.space();
+      }
+
+      switch (statement.get_argument_reference_type(i)) {
+      case nodes::Modifier::OUT:
+        printer.print(printer.print_words_instead_of_symbols() ? "out "
+                                                               : "-> ");
+        break;
+      case nodes::Modifier::IN:
+        printer.print(printer.print_words_instead_of_symbols() ? "in " : "<- ");
+        break;
+      case nodes::Modifier::REF:
+        printer.print(printer.print_words_instead_of_symbols() ? "ref "
+                                                               : "<> ");
+        break;
+      case nodes::Modifier::NONE:
+        break;
+      default: // TODO: handle errors ??
+        break;
+      }
+    }
+
+    print_identifier(*statement.get_argument(i), printer);
+
+    if (statement.get_argument_types_size() == 0) {
+      // TODO: can't be optional and result in same time
+
+      if (statement.is_argument_optional(i)) {
+        printer.print("?");
+      }
+
+      if (statement.is_argument_result(i)) {
+        printer.print("!");
+      }
+    }
+  }
+
+  if (statement.get_argument_types_size() > 0) { // TODO
+    printer.print(" :");
+    for (size_t i = 0; i < statement.get_argument_types_size(); ++i) {
+      printer.space();
+      if (statement.get_argument_annotation(i).has_value()) {
+        print_annotation(*statement.get_argument_annotation(i).value(),
+                         printer);
+        printer.space();
+      }
+
+      switch (statement.get_argument_reference_type(i)) {
+      case nodes::Modifier::OUT:
+        printer.print(printer.print_words_instead_of_symbols() ? "out "
+                                                               : "-> ");
+        break;
+      case nodes::Modifier::IN:
+        printer.print(printer.print_words_instead_of_symbols() ? "in " : "<- ");
+        break;
+      case nodes::Modifier::REF:
+        printer.print(printer.print_words_instead_of_symbols() ? "ref "
+                                                               : "<> ");
+        break;
+      case nodes::Modifier::NONE:
+        break;
+      default: // TODO: handle errors ??
+        break;
+      }
+
+      print_type(*statement.get_argument_type(i), printer);
+
+      // TODO: can't be optional and result in same time
+
+      if (statement.is_argument_optional(i)) {
+        printer.print("?");
+      }
+
+      if (statement.is_argument_result(i)) {
+        printer.print("!");
+      }
+    }
+  }
+
+  if (statement.get_expression().has_value()) {
+    printer.print(" = ");
+    print_expression(*statement.get_expression().value(), printer);
+  } else {
+    printer.print(";");
+  }
 } // IN PROGRESS
 
 void print_typeclass_definition(const nodes::TypeclassDefinition &statement,