diff --git a/boot/ast.cc b/boot/ast.cc
index 0ac0b81..c36ffde 100644
--- a/boot/ast.cc
+++ b/boot/ast.cc
@@ -103,7 +103,7 @@ namespace elna::boot
     {
     }
 
-    primitive_type_expression *type_expression::is_primitive()
+    named_type_expression *type_expression::is_named()
     {
         return nullptr;
     }
@@ -133,17 +133,22 @@ namespace elna::boot
         return nullptr;
     }
 
-    primitive_type_expression::primitive_type_expression(const struct position position, const std::string& name)
+    enumeration_type_expression *type_expression::is_enumeration()
+    {
+        return nullptr;
+    }
+
+    named_type_expression::named_type_expression(const struct position position, const std::string& name)
         : type_expression(position), name(name)
     {
     }
 
-    void primitive_type_expression::accept(parser_visitor *visitor)
+    void named_type_expression::accept(parser_visitor *visitor)
     {
         visitor->visit(this);
     }
 
-    primitive_type_expression *primitive_type_expression::is_primitive()
+    named_type_expression *named_type_expression::is_named()
     {
         return this;
     }
@@ -312,6 +317,26 @@ namespace elna::boot
         visitor->visit(this);
     }
 
+    procedure_type_expression *procedure_type_expression::is_procedure()
+    {
+        return this;
+    }
+
+    enumeration_type_expression::enumeration_type_expression(const struct position position, std::vector<std::string>&& members)
+        : type_expression(position), members(members)
+    {
+    }
+
+    void enumeration_type_expression::accept(parser_visitor *visitor)
+    {
+        visitor->visit(this);
+    }
+
+    enumeration_type_expression *enumeration_type_expression::is_enumeration()
+    {
+        return this;
+    }
+
     procedure_definition::procedure_definition(const struct position position, const std::string& identifier,
             const bool exported, procedure_type_expression *heading, block *body)
         : definition(position, identifier, exported), m_heading(heading), body(body)
@@ -323,11 +348,6 @@ namespace elna::boot
         visitor->visit(this);
     }
 
-    procedure_type_expression *procedure_type_expression::is_procedure()
-    {
-        return this;
-    }
-
     procedure_type_expression& procedure_definition::heading()
     {
         return *m_heading;
@@ -417,8 +437,8 @@ namespace elna::boot
         return this;
     }
 
-    defer_statement::defer_statement(const struct position position)
-        : node(position)
+    defer_statement::defer_statement(const struct position position, std::vector<statement *>&& statements)
+        : node(position), statements(std::move(statements))
     {
     }
 
@@ -754,7 +774,7 @@ namespace elna::boot
     }
 
     return_statement::return_statement(const struct position position, expression *return_expression)
-        : node(position), m_return_expression(return_expression)
+        : node(position), return_expression(return_expression)
     {
     }
 
@@ -768,14 +788,25 @@ namespace elna::boot
         return this;
     }
 
-    expression *return_statement::return_expression()
-    {
-        return m_return_expression;
-    }
-
     return_statement::~return_statement()
     {
-        delete m_return_expression;
+        delete this->return_expression;
+    }
+
+    case_statement::case_statement(const struct position position,
+            expression *condition, std::vector<switch_case>&& cases)
+        : node(position), m_condition(condition), cases(std::move(cases))
+    {
+    }
+
+    void case_statement::accept(parser_visitor *visitor)
+    {
+        visitor->visit(this);
+    }
+
+    expression& case_statement::condition()
+    {
+        return *m_condition;
     }
 
     assign_statement::assign_statement(const struct position position, designator_expression *lvalue,
diff --git a/boot/lexer.ll b/boot/lexer.ll
index 5029bf5..9827ba0 100644
--- a/boot/lexer.ll
+++ b/boot/lexer.ll
@@ -113,9 +113,12 @@ nil                     {
 xor                     {
                             return yy::parser::make_XOR(this->location);
                         }
-\|                      {
+or                     {
                             return yy::parser::make_OR(this->location);
                         }
+\|                      {
+                            return yy::parser::make_PIPE(this->location);
+                        }
 \~                      {
                             return yy::parser::make_NOT(this->location);
                         }
@@ -128,6 +131,12 @@ cast                    {
 defer                   {
                             return yy::parser::make_DEFER(this->location);
                         }
+case                    {
+                            return yy::parser::make_CASE(this->location);
+                        }
+of                      {
+                            return yy::parser::make_OF(this->location);
+                        }
 [A-Za-z_][A-Za-z0-9_]*  {
                             return yy::parser::make_IDENTIFIER(yytext, this->location);
                         }
diff --git a/boot/parser.yy b/boot/parser.yy
index ea6df6f..90657d9 100644
--- a/boot/parser.yy
+++ b/boot/parser.yy
@@ -111,31 +111,37 @@ along with GCC; see the file COPYING3.  If not see
     BEGIN_BLOCK "begin"
     END_BLOCK "end"
     DEFER "defer"
-%token OR "|" AND "&" XOR "xor"
+    CASE "case"
+    OF "of"
+    PIPE "|"
+%token OR "or" AND "&" XOR "xor"
     EQUALS "=" NOT_EQUAL "<>" LESS_THAN "<" GREATER_THAN ">" LESS_EQUAL "<=" GREATER_EQUAL ">="
     SHIFT_LEFT "<<" SHIFT_RIGHT ">>"
     PLUS "+" MINUS "-"
     MULTIPLICATION "*" DIVISION "/" REMAINDER "%"
 
-%left "|" "&" "xor"
+%left "or" "&" "xor"
 %left "=" "<>" "<" ">" "<=" ">="
 %left "<<" ">>"
 %left "+" "-"
 %left "*" "/" "%"
 
 %type <elna::boot::literal_expression *> literal;
+%type <std::vector<elna::boot::literal_expression *>> case_labels;
+%type <elna::boot::switch_case> switch_case;
+%type <std::vector<elna::boot::switch_case>> switch_cases;
 %type <elna::boot::constant_definition *> constant_definition;
 %type <std::vector<elna::boot::constant_definition *>> constant_part constant_definitions;
 %type <std::vector<elna::boot::variable_declaration *>> variable_declarations variable_part variable_declaration;
 %type <elna::boot::type_expression *> type_expression;
 %type <std::vector<elna::boot::type_expression *>> type_expressions;
 %type <elna::boot::traits_expression *> traits_expression;
-%type <elna::boot::expression *> expression operand qualident;
+%type <elna::boot::expression *> expression operand simple_expression;
+%type <elna::boot::field_access_expression *> qualident;
 %type <elna::boot::unary_expression *> unary_expression;
 %type <elna::boot::binary_expression *> binary_expression;
 %type <std::vector<elna::boot::expression *>> expressions actual_parameter_list;
 %type <elna::boot::designator_expression *> designator_expression;
-%type <elna::boot::assign_statement *> assign_statement;
 %type <elna::boot::procedure_call*> call_expression;
 %type <elna::boot::while_statement *> while_statement;
 %type <elna::boot::if_statement *> if_statement;
@@ -154,9 +160,9 @@ along with GCC; see the file COPYING3.  If not see
     optional_fields required_fields formal_parameters;
 %type <std::vector<elna::boot::conditional_statements *>> elsif_then_statements elsif_do_statements;
 %type <elna::boot::cast_expression *> cast_expression;
-%type <elna::boot::defer_statement *> defer_statement;
 %type <std::pair<std::string, bool>> identifier_definition;
 %type <std::vector<std::pair<std::string, bool>>> identifier_definitions;
+%type <std::vector<std::string>> identifiers;
 %%
 program:
     constant_part type_part variable_part procedure_part "begin" statements "end" "."
@@ -230,10 +236,6 @@ procedure_definitions:
 procedure_part:
     /* no procedure definitions */ {}
     | procedure_definitions { std::swap($$, $1); }
-assign_statement: designator_expression ":=" expression
-        {
-            $$ = new boot::assign_statement(boot::make_position(@1), $1, $3);
-        }
 call_expression: designator_expression actual_parameter_list
         {
             $$ = new boot::procedure_call(boot::make_position(@1), $1);
@@ -293,11 +295,6 @@ return_statement:
         {
             $$ = new boot::return_statement(boot::make_position(@1));
         }
-defer_statement: DEFER statements "end"
-        {
-            $$ = new boot::defer_statement(boot::make_position(@1));
-            std::swap($2, $$->statements);
-        }
 literal:
     INTEGER
         {
@@ -333,7 +330,7 @@ traits_expression:
             $$ = new boot::traits_expression(boot::make_position(@1), $1);
             std::swap($3, $$->parameters);
         }
-qualident:
+simple_expression:
     literal { $$ = $1; }
     | designator_expression { $$ = $1; }
     | traits_expression { $$ = $1; }
@@ -342,7 +339,7 @@ qualident:
     | "(" expression ")" { $$ = $2; }
 operand:
     unary_expression { $$ = $1; }
-    | qualident { $$ = $1; }
+    | simple_expression { $$ = $1; }
 expression:
     binary_expression { $$ = $1; }
     | operand { $$ = $1; }
@@ -396,7 +393,7 @@ binary_expression:
         {
             $$ = new boot::binary_expression(boot::make_position(@2), $1, $3, boot::binary_operator::conjunction);
         }
-    | expression "|" expression
+    | expression "or" expression
         {
             $$ = new boot::binary_expression(boot::make_position(@2), $1, $3, boot::binary_operator::disjunction);
         }
@@ -441,15 +438,12 @@ type_expressions:
         }
     | type_expression { $$.push_back($1); }
 designator_expression:
-    qualident "[" expression "]"
+    simple_expression "[" expression "]"
         {
             $$ = new boot::array_access_expression(boot::make_position(@2), $1, $3);
         }
-    | qualident "." IDENTIFIER
-        {
-            $$ = new boot::field_access_expression(boot::make_position(@2), $1, $3);
-        }
-    | qualident "^"
+    | qualident  { $$ = $1; }
+    | simple_expression "^"
         {
             $$ = new boot::dereference_expression(boot::make_position(@1), $1);
         }
@@ -457,13 +451,37 @@ designator_expression:
         {
             $$ = new boot::variable_expression(boot::make_position(@1), $1);
         }
+qualident: simple_expression "." IDENTIFIER
+        {
+            $$ = new boot::field_access_expression(boot::make_position(@2), $1, $3);
+        }
 statement:
-    assign_statement { $$ = $1; }
+    designator_expression ":=" expression
+        {
+            $$ = new boot::assign_statement(boot::make_position(@1), $1, $3);
+        }
     | while_statement { $$ = $1; }
     | if_statement { $$ = $1; }
     | return_statement { $$ = $1; }
     | call_expression { $$ = $1; }
-    | defer_statement { $$ = $1; }
+    | DEFER statements "end" { $$ = new boot::defer_statement(boot::make_position(@1), std::move($2)); }
+    | CASE expression "of" switch_cases "end"
+        { $$ = new boot::case_statement(boot::make_position(@1), $2, std::move($4)); }
+switch_case: case_labels ":" statements { $$ = { .labels = std::move($1), .statements = std::move($3) }; }
+switch_cases:
+    switch_case "|" switch_cases
+        {
+            std::swap($$, $3);
+            $$.emplace($$.cbegin(), $1);
+        }
+    | switch_case { $$.push_back($1); }
+case_labels:
+    literal "," case_labels
+        {
+            std::swap($$, $3);
+            $$.emplace($$.cbegin(), $1);
+        }
+    | literal { $$.push_back($1); }
 statements:
     statement ";" statements
         {
@@ -507,10 +525,21 @@ type_expression:
             std::swap(result->parameters, $3);
             $$ = result;
         }
+    | "(" identifiers ")"
+        {
+            $$ = new boot::enumeration_type_expression(boot::make_position(@1), std::move($2));
+        }
     | IDENTIFIER
         {
-            $$ = new boot::primitive_type_expression(boot::make_position(@1), $1);
+            $$ = new boot::named_type_expression(boot::make_position(@1), $1);
         }
+identifiers:
+    IDENTIFIER "," identifiers
+        {
+            std::swap($$, $3);
+            $$.emplace($$.cbegin(), std::move($1));
+        }
+    | IDENTIFIER { $$.emplace_back(std::move($1)); }
 variable_declaration: identifier_definitions ":" type_expression
         {
             std::shared_ptr<boot::type_expression> shared_type{ $3 };
@@ -561,16 +590,14 @@ type_definitions:
 type_part:
     /* no type definitions */ {}
     | "type" type_definitions { std::swap($$, $2); }
-formal_parameter: IDENTIFIER ":" type_expression
-        {
-            $$ = std::make_pair($1, $3);
-        }
+formal_parameter:
+    IDENTIFIER ":" type_expression { $$ = std::make_pair($1, $3); }
 formal_parameters:
     /* no formal parameters */ {}
     | formal_parameter "," formal_parameters
         {
             std::swap($$, $3);
-            $$.emplace($$.cbegin(), $1);
+            $$.emplace($$.cbegin(), std::move($1));
         }
     | formal_parameter { $$.emplace_back(std::move($1)); }
 actual_parameter_list:
diff --git a/boot/semantic.cc b/boot/semantic.cc
index 6c9f456..ad2e9d6 100644
--- a/boot/semantic.cc
+++ b/boot/semantic.cc
@@ -114,7 +114,7 @@ namespace elna::boot
         unresolved_declaration->reference = this->current_type;
     }
 
-    void declaration_visitor::visit(primitive_type_expression *type_expression)
+    void declaration_visitor::visit(named_type_expression *type_expression)
     {
         auto unresolved_alias = this->unresolved.find(type_expression->name);
 
@@ -177,13 +177,23 @@ namespace elna::boot
         this->current_type = type(result_type);
     }
 
+    void declaration_visitor::visit(enumeration_type_expression *type_expression)
+    {
+        std::shared_ptr<enumeration_type> result_type = std::make_shared<enumeration_type>(type_expression->members);
+
+        this->current_type = type(result_type);
+    }
+
     void declaration_visitor::visit(variable_declaration *declaration)
     {
         declaration->variable_type().accept(this);
     }
 
-    void declaration_visitor::visit(constant_definition *)
+    void declaration_visitor::visit(constant_definition *definition)
     {
+        definition->body().accept(this);
+
+        this->symbols->enter(definition->identifier, std::make_shared<constant_info>(this->current_literal));
     }
 
     void declaration_visitor::visit(procedure_definition *definition)
@@ -249,9 +259,9 @@ namespace elna::boot
 
     void declaration_visitor::visit(return_statement *statement)
     {
-        if (statement->return_expression() != nullptr)
+        if (statement->return_expression != nullptr)
         {
-            statement->return_expression()->accept(this);
+            statement->return_expression->accept(this);
         }
     }
 
@@ -263,6 +273,22 @@ namespace elna::boot
         }
     }
 
+    void declaration_visitor::visit(case_statement *statement)
+    {
+        statement->condition().accept(this);
+        for (const switch_case& case_block : statement->cases)
+        {
+            for (literal_expression *const case_label : case_block.labels)
+            {
+                case_label->accept(this);
+            }
+            for (struct statement *const statement : case_block.statements)
+            {
+                statement->accept(this);
+            }
+        }
+    }
+
     void declaration_visitor::visit(procedure_call *call)
     {
         call->callable().accept(this);
@@ -333,31 +359,38 @@ namespace elna::boot
         expression->base().accept(this);
     }
 
-    void declaration_visitor::visit(literal<std::int32_t> *)
+    void declaration_visitor::visit(literal<std::int32_t> *literal)
     {
+        this->current_literal = literal->value;
     }
 
-    void declaration_visitor::visit(literal<std::uint32_t> *)
+    void declaration_visitor::visit(literal<std::uint32_t> *literal)
     {
+        this->current_literal = literal->value;
     }
 
-    void declaration_visitor::visit(literal<double> *)
+    void declaration_visitor::visit(literal<double> *literal)
     {
+        this->current_literal = literal->value;
     }
 
-    void declaration_visitor::visit(literal<bool> *)
+    void declaration_visitor::visit(literal<bool> *literal)
     {
+        this->current_literal = literal->value;
     }
 
-    void declaration_visitor::visit(literal<unsigned char> *)
+    void declaration_visitor::visit(literal<unsigned char> *literal)
     {
+        this->current_literal = literal->value;
     }
 
-    void declaration_visitor::visit(literal<std::nullptr_t> *)
+    void declaration_visitor::visit(literal<std::nullptr_t> *literal)
     {
+        this->current_literal = literal->value;
     }
 
-    void declaration_visitor::visit(literal<std::string> *)
+    void declaration_visitor::visit(literal<std::string> *literal)
     {
+        this->current_literal = literal->value;
     }
 }
diff --git a/boot/symbol.cc b/boot/symbol.cc
index 643ea4e..9712935 100644
--- a/boot/symbol.cc
+++ b/boot/symbol.cc
@@ -58,6 +58,11 @@ namespace elna::boot
     {
     }
 
+    type::type(std::shared_ptr<enumeration_type> enumeration)
+        : tag(type_tag::enumeration), enumeration(enumeration)
+    {
+    }
+
     void type::copy(const type& other)
     {
         switch (other.tag)
@@ -85,6 +90,9 @@ namespace elna::boot
         case type_tag::procedure:
             new (&procedure) std::shared_ptr<procedure_type>(other.procedure);
             break;
+        case type_tag::enumeration:
+            new (&enumeration) std::shared_ptr<enumeration_type>(other.enumeration);
+            break;
         }
     }
 
@@ -121,6 +129,9 @@ namespace elna::boot
         case type_tag::procedure:
             new (&procedure) std::shared_ptr<procedure_type>(std::move(other.procedure));
             break;
+        case type_tag::enumeration:
+            new (&enumeration) std::shared_ptr<enumeration_type>(std::move(other.enumeration));
+            break;
         }
     }
 
@@ -178,6 +189,9 @@ namespace elna::boot
         case type_tag::procedure:
             this->procedure.~shared_ptr<procedure_type>();
             break;
+        case type_tag::enumeration:
+            this->enumeration.~shared_ptr<enumeration_type>();
+            break;
         }
     }
 
@@ -223,6 +237,12 @@ namespace elna::boot
         return tag == type_tag::procedure ? this->procedure : nullptr;
     }
 
+    template<>
+    std::shared_ptr<enumeration_type> type::get<enumeration_type>() const
+    {
+        return tag == type_tag::enumeration ? this->enumeration : nullptr;
+    }
+
     bool type::empty() const
     {
         return tag == type_tag::empty;
@@ -253,6 +273,11 @@ namespace elna::boot
     {
     }
 
+    enumeration_type::enumeration_type(const std::vector<std::string>& members)
+        : members(members)
+    {
+    }
+
     info::~info()
     {
     }
@@ -287,6 +312,11 @@ namespace elna::boot
         return std::static_pointer_cast<procedure_info>(shared_from_this());
     }
 
+    constant_info::constant_info(const variant& symbol)
+        : symbol(symbol)
+    {
+    }
+
     std::shared_ptr<symbol_table> builtin_symbol_table()
     {
         auto result = std::make_shared<symbol_table>();
diff --git a/gcc/elna-diagnostic.cc b/gcc/elna-diagnostic.cc
index ea92ece..ddcbf15 100644
--- a/gcc/elna-diagnostic.cc
+++ b/gcc/elna-diagnostic.cc
@@ -78,7 +78,7 @@ namespace elna::gcc
         {
             return "()";
         }
-        else if (is_pointer_type(unqualified_type))
+        else if (POINTER_TYPE_P(unqualified_type))
         {
             tree pointer_target_type = TREE_TYPE(type);
 
@@ -129,6 +129,10 @@ namespace elna::gcc
         {
             return print_aggregate_name(unqualified_type, "union");
         }
+        else if (TREE_CODE(type) == ENUMERAL_TYPE)
+        {
+            return print_aggregate_name(unqualified_type, "enumeration");
+        }
         else
         {
             return "<<unknown-type>>";
diff --git a/gcc/elna-generic.cc b/gcc/elna-generic.cc
index ff13659..ed68304 100644
--- a/gcc/elna-generic.cc
+++ b/gcc/elna-generic.cc
@@ -57,6 +57,10 @@ namespace elna::gcc
         {
             return make_node(UNION_TYPE);
         }
+        else if (auto reference = type.get<boot::enumeration_type>())
+        {
+            return make_node(ENUMERAL_TYPE);
+        }
         else if (auto reference = type.get<boot::pointer_type>())
         {
             return build_global_pointer_type(get_inner_alias(reference->base, symbols, unresolved, path));
@@ -227,7 +231,7 @@ namespace elna::gcc
                     build_global_pointer_type(expression_type), this->current_expression);
             build_procedure_call(call_location, this->current_expression, call->arguments);
         }
-        else if (is_pointer_type(expression_type) && TREE_CODE(TREE_TYPE(expression_type)) == FUNCTION_TYPE)
+        else if (POINTER_TYPE_P(expression_type) && TREE_CODE(TREE_TYPE(expression_type)) == FUNCTION_TYPE)
         {
             build_procedure_call(call_location, this->current_expression, call->arguments);
         }
@@ -247,8 +251,7 @@ namespace elna::gcc
         expression->value().accept(this);
         tree cast_source = TREE_TYPE(this->current_expression);
 
-        if ((is_primitive_type(cast_target) || is_pointer_type(cast_target))
-                && (is_primitive_type(cast_source) || is_pointer_type(cast_source)))
+        if (is_castable_type(cast_target) && (is_castable_type(cast_source)))
         {
             this->current_expression = build1_loc(get_location(&expression->position()), CONVERT_EXPR,
                     cast_target, this->current_expression);
@@ -303,7 +306,8 @@ namespace elna::gcc
         for (boot::constant_definition *const constant : program->constants)
         {
             constant->accept(this);
-        } for (boot::type_definition *const type : program->types)
+        }
+        for (boot::type_definition *const type : program->types)
         {
             type->accept(this);
         }
@@ -514,7 +518,7 @@ namespace elna::gcc
     tree generic_visitor::build_comparison_operation(boot::binary_expression *expression,
             tree_code operator_code, tree left, tree right)
     {
-        return build_binary_operation(is_numeric_type(TREE_TYPE(left)) || is_pointer_type(TREE_TYPE(left)),
+        return build_binary_operation(is_numeric_type(TREE_TYPE(left)) || POINTER_TYPE_P(TREE_TYPE(left)),
                 expression, operator_code, left, right, elna_bool_type_node);
     }
 
@@ -624,7 +628,7 @@ namespace elna::gcc
 
         location_t expression_location = get_location(&expression->position());
 
-        if ((is_pointer_type(left_type) || is_pointer_type(right_type))
+        if ((POINTER_TYPE_P(left_type) || POINTER_TYPE_P(right_type))
                 && (expression->operation() == boot::binary_operator::sum
                     || expression->operation() == boot::binary_operator::subtraction))
         {
@@ -867,7 +871,7 @@ namespace elna::gcc
                 get_identifier(declaration->identifier.c_str()), this->current_expression);
         bool result = this->symbols->enter(declaration->identifier, declaration_tree);
 
-        if (is_pointer_type(this->current_expression))
+        if (POINTER_TYPE_P(this->current_expression))
         {
             DECL_INITIAL(declaration_tree) = elna_pointer_nil_node;
         }
@@ -976,7 +980,7 @@ namespace elna::gcc
         {
             return false;
         }
-        else if (!is_integral_type(this->current_expression))
+        else if (!is_integral_type(this->current_expression) && TREE_CODE(this->current_expression) != ENUMERAL_TYPE)
         {
             error_at(get_location(&trait->position()), "Type '%s' does not support trait '%s'",
                     print_type(this->current_expression).c_str(), trait->name.c_str());
@@ -1030,7 +1034,7 @@ namespace elna::gcc
                 return;
             }
             trait->parameters.front()->accept(this);
-            auto field_type = trait->parameters.at(1)->is_primitive();
+            auto field_type = trait->parameters.at(1)->is_named();
 
             if (field_type == nullptr)
             {
@@ -1076,6 +1080,21 @@ namespace elna::gcc
             this->current_expression = build1(ADDR_EXPR,
                     build_qualified_type(ptr_type, TYPE_QUAL_CONST), this->current_expression);
         }
+        else if (TREE_CODE(aggregate_type) == ENUMERAL_TYPE)
+        {
+            tree iterator{ NULL_TREE };
+
+            for (iterator = TYPE_VALUES(aggregate_type); iterator != NULL_TREE; iterator = TREE_CHAIN(iterator))
+            {
+                if (IDENTIFIER_POINTER(TREE_PURPOSE(iterator)) == expression->field())
+                {
+                    this->current_expression = TREE_VALUE(iterator);
+                    return;
+                }
+            }
+            this->current_expression = error_mark_node;
+            error_at(expression_location, "Unknown enumeration member '%s'", expression->field().c_str());
+        }
         else
         {
             tree field_declaration = find_field_by_name(expression_location,
@@ -1096,7 +1115,7 @@ namespace elna::gcc
         location_t expression_location = get_location(&expression->position());
         tree expression_type = TREE_TYPE(this->current_expression);
 
-        if (is_pointer_type(expression_type))
+        if (POINTER_TYPE_P(expression_type))
         {
             this->current_expression = build1_loc(expression_location, INDIRECT_REF,
                     TREE_TYPE(expression_type), this->current_expression);
@@ -1201,16 +1220,6 @@ namespace elna::gcc
         append_statement(else_label_expr);
     }
 
-    tree generic_visitor::build_label_decl(const char *name, location_t loc)
-    {
-        auto label_decl = build_decl(loc,
-                LABEL_DECL, get_identifier(name), void_type_node);
-
-        DECL_CONTEXT(label_decl) = current_function_decl;
-
-        return label_decl;
-    }
-
     void generic_visitor::visit(boot::while_statement *statement)
     {
         auto prerequisite_location = get_location(&statement->body().prerequisite().position());
@@ -1245,7 +1254,7 @@ namespace elna::gcc
 
     void generic_visitor::visit(boot::return_statement *statement)
     {
-        boot::expression *return_expression = statement->return_expression();
+        boot::expression *return_expression = statement->return_expression;
         location_t statement_position = get_location(&statement->position());
         tree set_result{ NULL_TREE };
         tree return_type = TREE_TYPE(TREE_TYPE(current_function_decl));
@@ -1285,7 +1294,7 @@ namespace elna::gcc
         this->current_expression = NULL_TREE;
     }
 
-    void generic_visitor::visit(boot::primitive_type_expression *type)
+    void generic_visitor::visit(boot::named_type_expression *type)
     {
         auto looked_up = this->unresolved.find(type->name);
         tree symbol;
@@ -1362,10 +1371,85 @@ namespace elna::gcc
         this->current_expression = build_global_pointer_type(procedure_type_node);
     }
 
+    void generic_visitor::visit(boot::enumeration_type_expression *type)
+    {
+        tree composite_type_node = this->current_expression == NULL_TREE
+            ? make_node(ENUMERAL_TYPE)
+            : this->current_expression;
+        location_t enum_location = get_location(&type->position());
+        const tree base_type = integer_type_node;
+
+        TREE_TYPE(composite_type_node) = base_type;
+        ENUM_IS_SCOPED(composite_type_node) = 1;
+
+        tree *pp = &TYPE_VALUES(composite_type_node);
+        std::size_t order{ 1 };
+
+        for (const std::string& member : type->members)
+        {
+            tree member_name = get_identifier(member.c_str());
+            tree member_declaration = build_decl(enum_location, CONST_DECL, member_name, composite_type_node);
+
+            DECL_CONTEXT(member_declaration) = composite_type_node;
+            DECL_INITIAL(member_declaration) = build_int_cst_type(composite_type_node, order++);
+            TREE_CONSTANT(member_declaration) = 1;
+            TREE_READONLY(member_declaration) = 1;
+
+            TYPE_MAX_VALUE(composite_type_node) = DECL_INITIAL(member_declaration);
+
+            *pp = build_tree_list(member_name, member_declaration);
+            pp = &TREE_CHAIN(*pp);
+        }
+        TYPE_MIN_VALUE(composite_type_node) = DECL_INITIAL(TREE_VALUE(TYPE_VALUES(composite_type_node)));
+        TYPE_UNSIGNED(composite_type_node) = TYPE_UNSIGNED(base_type);
+        SET_TYPE_ALIGN(composite_type_node, TYPE_ALIGN(base_type));
+        TYPE_SIZE(composite_type_node) = NULL_TREE;
+        TYPE_PRECISION(composite_type_node) = TYPE_PRECISION(base_type);
+
+        layout_type(composite_type_node);
+    }
+
     void generic_visitor::visit(boot::defer_statement *statement)
     {
         enter_scope();
         visit_statements(statement->statements);
         defer(leave_scope());
     }
+
+    void generic_visitor::visit(boot::case_statement *statement)
+    {
+        statement->condition().accept(this);
+
+        tree condition_expression = this->current_expression;
+        tree end_label_declaration = create_artificial_label(UNKNOWN_LOCATION);
+        tree switch_statements = alloc_stmt_list();
+
+        for (const boot::switch_case& case_block : statement->cases)
+        {
+            for (boot::literal_expression *const case_label : case_block.labels)
+            {
+                case_label->accept(this);
+                tree case_label_declaration = create_artificial_label(get_location(&case_label->position()));
+                tree case_expression = build_case_label(this->current_expression, NULL_TREE, case_label_declaration);
+
+                append_to_statement_list(case_expression, &switch_statements);
+            }
+            enter_scope();
+            visit_statements(case_block.statements);
+            append_to_statement_list(leave_scope(), &switch_statements);
+            tree goto_end = fold_build1(GOTO_EXPR, void_type_node, end_label_declaration);
+
+            append_to_statement_list(goto_end, &switch_statements);
+            TREE_USED(end_label_declaration) = 1;
+        }
+        tree switch_expression = build2(SWITCH_EXPR, TREE_TYPE(condition_expression),
+                condition_expression, switch_statements);
+
+        append_statement(switch_expression);
+
+        tree end_label_expression = build1(LABEL_EXPR, void_type_node, end_label_declaration);
+        append_statement(end_label_expression);
+
+        this->current_expression = NULL_TREE;
+    }
 }
diff --git a/gcc/elna-tree.cc b/gcc/elna-tree.cc
index 635e4b5..a2d7b5a 100644
--- a/gcc/elna-tree.cc
+++ b/gcc/elna-tree.cc
@@ -26,12 +26,6 @@ along with GCC; see the file COPYING3.  If not see
 
 namespace elna::gcc
 {
-    bool is_pointer_type(tree type)
-    {
-        gcc_assert(TYPE_P(type));
-        return TREE_CODE(type) == POINTER_TYPE;
-    }
-
     bool is_integral_type(tree type)
     {
         gcc_assert(TYPE_P(type));
@@ -62,10 +56,12 @@ namespace elna::gcc
         return type == NULL_TREE || type == void_type_node;
     }
 
-    bool is_aggregate_type(tree type)
+    bool is_castable_type(tree type)
     {
         gcc_assert(TYPE_P(type));
-        return TREE_CODE(type) == RECORD_TYPE || TREE_CODE(type) == UNION_TYPE;
+        auto code = TREE_CODE(type);
+
+        return is_primitive_type(type) || POINTER_TYPE_P(type) || code == ENUMERAL_TYPE;
     }
 
     bool are_compatible_pointers(tree lhs_type, tree rhs)
@@ -73,8 +69,8 @@ namespace elna::gcc
         gcc_assert(TYPE_P(lhs_type));
         tree rhs_type = TREE_TYPE(rhs);
 
-        return (is_pointer_type(lhs_type) && rhs == elna_pointer_nil_node)
-            || (is_pointer_type(lhs_type) && lhs_type == rhs_type);
+        return (POINTER_TYPE_P(lhs_type) && rhs == elna_pointer_nil_node)
+            || (POINTER_TYPE_P(lhs_type) && lhs_type == rhs_type);
     }
 
     tree prepare_rvalue(tree rvalue)
@@ -152,12 +148,12 @@ namespace elna::gcc
             tree pointer{ NULL_TREE };
             tree offset{ NULL_TREE };
 
-            if (is_pointer_type(left_type) && is_integral_type(right_type))
+            if (POINTER_TYPE_P(left_type) && is_integral_type(right_type))
             {
                 pointer = left;
                 offset = right;
             }
-            else if (is_integral_type(left_type) && is_pointer_type(right_type))
+            else if (is_integral_type(left_type) && POINTER_TYPE_P(right_type))
             {
                 pointer = right;
                 offset = left;
@@ -175,7 +171,7 @@ namespace elna::gcc
         }
         else if (binary_operator == boot::binary_operator::subtraction)
         {
-            if (is_pointer_type(left_type) && is_integral_type(right_type))
+            if (POINTER_TYPE_P(left_type) && is_integral_type(right_type))
             {
                 tree pointer_type = left_type;
                 tree offset_type = right_type;
@@ -187,7 +183,7 @@ namespace elna::gcc
                 convert_expression = fold_build1(NEGATE_EXPR, sizetype, convert_expression);
                 return fold_build2(POINTER_PLUS_EXPR, pointer_type, left, convert_expression);
             }
-            else if (is_pointer_type(left_type) && is_pointer_type(right_type) && left_type == right_type)
+            else if (POINTER_TYPE_P(left_type) && POINTER_TYPE_P(right_type) && left_type == right_type)
             {
                 return fold_build2(POINTER_DIFF_EXPR, ssizetype, left, right);
             }
@@ -224,9 +220,9 @@ namespace elna::gcc
         }
         tree field_declaration = TYPE_FIELDS(type);
 
-        if (!is_aggregate_type(type))
+        if (!RECORD_OR_UNION_TYPE_P(type))
         {
-            error_at(expression_location, "type '%s' does not have a field named '%s'",
+            error_at(expression_location, "Type '%s' does not have a field named '%s'",
                     print_type(type).c_str(), field_name.c_str());
             return error_mark_node;
         }
@@ -243,7 +239,7 @@ namespace elna::gcc
         }
         if (field_declaration == NULL_TREE)
         {
-            error_at(expression_location, "record type does not have a field named '%s'", field_name.c_str());
+            error_at(expression_location, "Aggregate type does not have a field '%s'", field_name.c_str());
             return error_mark_node;
         }
         return field_declaration;
@@ -253,4 +249,13 @@ namespace elna::gcc
     {
         return build_pointer_type_for_mode(type, VOIDmode, true);
     }
+
+    tree build_label_decl(const char *name, location_t loc)
+    {
+        auto label_decl = build_decl(loc, LABEL_DECL, get_identifier(name), void_type_node);
+
+        DECL_CONTEXT(label_decl) = current_function_decl;
+
+        return label_decl;
+    }
 }
diff --git a/include/elna/boot/ast.h b/include/elna/boot/ast.h
index 65a3f5b..c5d2c76 100644
--- a/include/elna/boot/ast.h
+++ b/include/elna/boot/ast.h
@@ -62,17 +62,19 @@ namespace elna::boot
     class if_statement;
     class while_statement;
     class return_statement;
+    class case_statement;
     class traits_expression;
     class block;
     class program;
     class binary_expression;
     class unary_expression;
-    class primitive_type_expression;
+    class named_type_expression;
     class array_type_expression;
     class pointer_type_expression;
     class record_type_expression;
     class union_type_expression;
     class procedure_type_expression;
+    class enumeration_type_expression;
     class variable_expression;
     class array_access_expression;
     class field_access_expression;
@@ -100,16 +102,18 @@ namespace elna::boot
         virtual void visit(while_statement *) = 0;
         virtual void visit(return_statement *) = 0;
         virtual void visit(defer_statement *) = 0;
+        virtual void visit(case_statement *) = 0;
         virtual void visit(block *) = 0;
         virtual void visit(program *) = 0;
         virtual void visit(binary_expression *) = 0;
         virtual void visit(unary_expression *) = 0;
-        virtual void visit(primitive_type_expression *) = 0;
+        virtual void visit(named_type_expression *) = 0;
         virtual void visit(array_type_expression *) = 0;
         virtual void visit(pointer_type_expression *) = 0;
         virtual void visit(record_type_expression *) = 0;
         virtual void visit(union_type_expression *) = 0;
         virtual void visit(procedure_type_expression *) = 0;
+        virtual void visit(enumeration_type_expression *) = 0;
         virtual void visit(variable_expression *) = 0;
         virtual void visit(array_access_expression *) = 0;
         virtual void visit(field_access_expression *) = 0;
@@ -188,28 +192,29 @@ namespace elna::boot
     class type_expression : public node
     {
     public:
-        virtual primitive_type_expression *is_primitive();
+        virtual named_type_expression *is_named();
         virtual array_type_expression *is_array();
         virtual pointer_type_expression *is_pointer();
         virtual record_type_expression *is_record();
         virtual union_type_expression *is_union();
         virtual procedure_type_expression *is_procedure();
+        virtual enumeration_type_expression *is_enumeration();
 
     protected:
         type_expression(const struct position position);
     };
 
     /**
-     * Expression defining a basic type.
+     * Expression refering to a type by its name.
      */
-    class primitive_type_expression : public type_expression
+    class named_type_expression : public type_expression
     {
     public:
         const std::string name;
 
-        primitive_type_expression(const struct position position, const std::string& name);
+        named_type_expression(const struct position position, const std::string& name);
         void accept(parser_visitor *visitor) override;
-        primitive_type_expression *is_primitive() override;
+        named_type_expression *is_named() override;
     };
 
     class array_type_expression : public type_expression
@@ -269,6 +274,20 @@ namespace elna::boot
         union_type_expression *is_union() override;
     };
 
+    /**
+     * Enumeration type.
+     */
+    class enumeration_type_expression : public type_expression
+    {
+    public:
+        const std::vector<std::string> members;
+
+        enumeration_type_expression(const struct position, std::vector<std::string>&& members);
+
+        void accept(parser_visitor *visitor) override;
+        enumeration_type_expression *is_enumeration() override;
+    };
+
     /**
      * Variable declaration.
      */
@@ -291,14 +310,6 @@ namespace elna::boot
     class literal_expression : public expression
     {
     public:
-        virtual literal<std::int32_t> *is_int() = 0;
-        virtual literal<std::uint32_t> *is_word() = 0;
-        virtual literal<double> *is_float() = 0;
-        virtual literal<bool> *is_bool() = 0;
-        virtual literal<unsigned char> *is_char() = 0;
-        virtual literal<std::nullptr_t> *is_nil() = 0;
-        virtual literal<std::string> *is_string() = 0;
-
         literal_expression *is_literal() override;
 
     protected:
@@ -428,18 +439,34 @@ namespace elna::boot
 
     class return_statement : public statement
     {
-        expression *m_return_expression{ nullptr };
-
     public:
+        expression *const return_expression{ nullptr };
+
         return_statement(const struct position position, expression *return_expression = nullptr);
         void accept(parser_visitor *visitor) override;
         virtual return_statement *is_return() override;
 
-        expression *return_expression();
-
         virtual ~return_statement() override;
     };
 
+    struct switch_case
+    {
+        std::vector<literal_expression *> labels;
+        std::vector<statement *> statements;
+    };
+
+    class case_statement : public statement
+    {
+        expression *m_condition;
+
+    public:
+        const std::vector<switch_case> cases;
+
+        case_statement(const struct position position, expression *condition, std::vector<switch_case>&& cases);
+        void accept(parser_visitor *visitor) override;
+        expression& condition();
+    };
+
     class designator_expression : public expression
     {
     public:
@@ -635,90 +662,6 @@ namespace elna::boot
         {
         }
 
-        literal<std::int32_t> *is_int() override
-        {
-            if (std::is_same<T, std::int32_t>::value)
-            {
-                return reinterpret_cast<literal<std::int32_t> *>(this);
-            }
-            else
-            {
-                return nullptr;
-            }
-        }
-
-        literal<std::uint32_t> *is_word() override
-        {
-            if (std::is_same<T, std::uint32_t>::value)
-            {
-                return reinterpret_cast<literal<std::uint32_t> *>(this);
-            }
-            else
-            {
-                return nullptr;
-            }
-        }
-
-        literal<double> *is_float() override
-        {
-            if (std::is_same<T, double>::value)
-            {
-                return reinterpret_cast<literal<double> *>(this);
-            }
-            else
-            {
-                return nullptr;
-            }
-        }
-
-        literal<bool> *is_bool() override
-        {
-            if (std::is_same<T, bool>::value)
-            {
-                return reinterpret_cast<literal<bool> *>(this);
-            }
-            else
-            {
-                return nullptr;
-            }
-        }
-
-        literal<unsigned char> *is_char() override
-        {
-            if (std::is_same<T, unsigned char>::value)
-            {
-                return reinterpret_cast<literal<unsigned char> *>(this);
-            }
-            else
-            {
-                return nullptr;
-            }
-        }
-
-        literal<std::nullptr_t> *is_nil() override
-        {
-            if (std::is_same<T, std::nullptr_t>::value)
-            {
-                return reinterpret_cast<literal<std::nullptr_t> *>(this);
-            }
-            else
-            {
-                return nullptr;
-            }
-        }
-
-        literal<std::string> *is_string() override
-        {
-            if (std::is_same<T, std::string>::value)
-            {
-                return reinterpret_cast<literal<std::string> *>(this);
-            }
-            else
-            {
-                return nullptr;
-            }
-        }
-
         void accept(parser_visitor *visitor) override
         {
             visitor->visit(this);
@@ -728,9 +671,9 @@ namespace elna::boot
     class defer_statement : public statement
     {
     public:
-        std::vector<statement *> statements;
+        const std::vector<statement *> statements;
 
-        defer_statement(const struct position position);
+        defer_statement(const struct position position, std::vector<statement *>&& statements);
         void accept(parser_visitor *visitor) override;
         defer_statement *is_defer() override;
 
diff --git a/include/elna/boot/semantic.h b/include/elna/boot/semantic.h
index 76de3dd..a74b9b6 100644
--- a/include/elna/boot/semantic.h
+++ b/include/elna/boot/semantic.h
@@ -49,6 +49,8 @@ namespace elna::boot
     class declaration_visitor final : public parser_visitor, public error_container
     {
         type current_type;
+        constant_info::variant current_literal;
+
         std::shared_ptr<symbol_table> symbols;
 
         procedure_type build_procedure(procedure_type_expression& type_expression);
@@ -58,7 +60,7 @@ namespace elna::boot
 
         explicit declaration_visitor(const char *path, std::shared_ptr<symbol_table> symbols);
 
-        void visit(primitive_type_expression *type_expression) override;
+        void visit(named_type_expression *type_expression) override;
         void visit(array_type_expression *type_expression) override;
         void visit(pointer_type_expression *type_expression) override;
         void visit(program *program) override;
@@ -66,15 +68,17 @@ namespace elna::boot
         void visit(record_type_expression *type_expression) override;
         void visit(union_type_expression *type_expression) override;
         void visit(procedure_type_expression *type_expression) override;
+        void visit(enumeration_type_expression *type_expression) override;
 
         void visit(variable_declaration *declaration) override;
-        void visit(constant_definition *) override;
+        void visit(constant_definition *definition) override;
         void visit(procedure_definition *definition) override;
         void visit(assign_statement *statement) override;
         void visit(if_statement *statement) override;
         void visit(while_statement *statement) override;
         void visit(return_statement *statement) override;
         void visit(defer_statement *statement) override;
+        void visit(case_statement *statement) override;
         void visit(procedure_call *call) override;
         void visit(block *block) override;
         void visit(cast_expression *expression) override;
@@ -85,12 +89,12 @@ namespace elna::boot
         void visit(array_access_expression *expression) override;
         void visit(field_access_expression *expression) override;
         void visit(dereference_expression *expression) override;
-        void visit(literal<std::int32_t> *) override;
-        void visit(literal<std::uint32_t> *) override;
-        void visit(literal<double> *) override;
-        void visit(literal<bool> *) override;
-        void visit(literal<unsigned char> *) override;
-        void visit(literal<std::nullptr_t> *) override;
-        void visit(literal<std::string> *) override;
+        void visit(literal<std::int32_t> *literal) override;
+        void visit(literal<std::uint32_t> *literal) override;
+        void visit(literal<double> *literal) override;
+        void visit(literal<bool> *literal) override;
+        void visit(literal<unsigned char> *literal) override;
+        void visit(literal<std::nullptr_t> *literal) override;
+        void visit(literal<std::string> *literal) override;
     };
 }
diff --git a/include/elna/boot/symbol.h b/include/elna/boot/symbol.h
index 45629c8..ba48e17 100644
--- a/include/elna/boot/symbol.h
+++ b/include/elna/boot/symbol.h
@@ -34,6 +34,7 @@ namespace elna::boot
     class pointer_type;
     class array_type;
     class procedure_type;
+    class enumeration_type;
 
     class type
     {
@@ -46,7 +47,8 @@ namespace elna::boot
             _union,
             pointer,
             array,
-            procedure
+            procedure,
+            enumeration
         };
         type_tag tag{ type_tag::empty };
         union
@@ -58,6 +60,7 @@ namespace elna::boot
             std::shared_ptr<pointer_type> pointer;
             std::shared_ptr<array_type> array;
             std::shared_ptr<procedure_type> procedure;
+            std::shared_ptr<enumeration_type> enumeration;
         };
 
         void copy(const type& other);
@@ -72,6 +75,7 @@ namespace elna::boot
         explicit type(std::shared_ptr<pointer_type> pointer);
         explicit type(std::shared_ptr<array_type> array);
         explicit type(std::shared_ptr<procedure_type> procedure);
+        explicit type(std::shared_ptr<enumeration_type> enumeration);
 
         type(const type& other);
         type& operator=(const type& other);
@@ -141,8 +145,16 @@ namespace elna::boot
         procedure_type(return_t return_type = return_t());
     };
 
+    struct enumeration_type
+    {
+        std::vector<std::string> members;
+
+        explicit enumeration_type(const std::vector<std::string>& members);
+    };
+
     class type_info;
     class procedure_info;
+    class constant_info;
 
     class info : public std::enable_shared_from_this<info>
     {
@@ -174,6 +186,17 @@ namespace elna::boot
         std::shared_ptr<procedure_info> is_procedure() override;
     };
 
+    class constant_info : public info
+    {
+    public:
+        using variant = typename
+            std::variant<std::int32_t, std::uint32_t, double, bool, unsigned char, std::nullptr_t, std::string>;
+
+        const variant symbol;
+
+        explicit constant_info(const variant& symbol);
+    };
+
     /**
      * Symbol table.
      */
diff --git a/include/elna/gcc/elna-generic.h b/include/elna/gcc/elna-generic.h
index dca60bb..c2f13da 100644
--- a/include/elna/gcc/elna-generic.h
+++ b/include/elna/gcc/elna-generic.h
@@ -47,7 +47,6 @@ namespace elna::gcc
         std::unordered_map<std::string, tree> unresolved;
 
         void declare_procedure(boot::procedure_definition *const definition);
-        tree build_label_decl(const char *name, location_t loc);
         tree build_procedure_type(boot::procedure_type_expression& type);
         void build_composite_type(const std::vector<boot::field_declaration>& fields,
                 tree composite_type_node);
@@ -101,13 +100,15 @@ namespace elna::gcc
         void visit(boot::assign_statement *statement) override;
         void visit(boot::if_statement *statement) override;
         void visit(boot::while_statement *statement) override;
-        void visit(boot::primitive_type_expression *type) override;
+        void visit(boot::named_type_expression *type) override;
         void visit(boot::array_type_expression *type) override;
         void visit(boot::pointer_type_expression *type) override;
         void visit(boot::record_type_expression *type) override;
         void visit(boot::union_type_expression *type) override;
         void visit(boot::procedure_type_expression *type) override;
+        void visit(boot::enumeration_type_expression *type) override;
         void visit(boot::return_statement *statement) override;
         void visit(boot::defer_statement *statement) override;
+        void visit(boot::case_statement *statement) override;
     };
 }
diff --git a/include/elna/gcc/elna-tree.h b/include/elna/gcc/elna-tree.h
index 4f026e6..223fe52 100644
--- a/include/elna/gcc/elna-tree.h
+++ b/include/elna/gcc/elna-tree.h
@@ -33,7 +33,6 @@ namespace elna::gcc
 {
     using symbol_table = boot::symbol_map<tree, tree, NULL_TREE>;
 
-    bool is_pointer_type(tree type);
     bool is_integral_type(tree type);
     bool is_numeric_type(tree type);
     bool is_primitive_type(tree type);
@@ -42,9 +41,9 @@ namespace elna::gcc
 
     /**
      * \param type The type to evaluate.
-     * \return Whether the given type is record or union.
+     * \return Whether this type can be converted to another type.
      */
-    bool is_aggregate_type(tree type);
+    bool is_castable_type(tree type);
 
     /**
      * \param lhs Left hand value.
@@ -82,4 +81,5 @@ namespace elna::gcc
     tree build_field(location_t location, tree record_type, const std::string name, tree type);
     tree find_field_by_name(location_t expression_location, tree type, const std::string& field_name);
     tree build_global_pointer_type(tree type);
+    tree build_label_decl(const char *name, location_t loc);
 }
diff --git a/source.elna b/source.elna
index 695b0e1..efbc560 100644
--- a/source.elna
+++ b/source.elna
@@ -3,67 +3,69 @@ const
   SEEK_CUR* = 1;
   SEEK_END* = 2;
 
-  TOKEN_IDENTIFIER* = 1;
-  TOKEN_IF* = 2;
-  TOKEN_THEN* = 3;
-  TOKEN_ELSE* = 4;
-  TOKEN_ELSIF* = 5;
-  TOKEN_WHILE* = 6;
-  TOKEN_DO* = 7;
-  TOKEN_PROC* = 8;
-  TOKEN_BEGIN* = 9;
-  TOKEN_END* = 10;
-  TOKEN_EXTERN* = 11;
-  TOKEN_CONST* = 12;
-  TOKEN_VAR* = 13;
-  TOKEN_ARRAY* = 14;
-  TOKEN_OF* = 15;
-  TOKEN_TYPE* = 16;
-  TOKEN_RECORD* = 17;
-  TOKEN_UNION* = 18;
-  TOKEN_POINTER* = 19;
-  TOKEN_TO* = 20;
-  TOKEN_BOOLEAN* = 21;
-  TOKEN_NIL* = 22;
-  TOKEN_AND* = 23;
-  TOKEN_OR* = 24;
-  TOKEN_NOT* = 25;
-  TOKEN_RETURN* = 26;
-  TOKEN_CAST* = 27;
-  TOKEN_SHIFT_LEFT* = 28;
-  TOKEN_SHIFT_RIGHT* = 29;
-  TOKEN_LEFT_PAREN* = 30;
-  TOKEN_RIGHT_PAREN* = 31;
-  TOKEN_LEFT_SQUARE* = 32;
-  TOKEN_RIGHT_SQUARE* = 33;
-  TOKEN_GREATER_EQUAL* = 34;
-  TOKEN_LESS_EQUAL* = 35;
-  TOKEN_GREATER_THAN* = 36;
-  TOKEN_LESS_THAN* = 37;
-  TOKEN_NOT_EQUAL* = 38;
-  TOKEN_EQUAL* = 39;
-  TOKEN_SEMICOLON* = 40;
-  TOKEN_DOT* = 41;
-  TOKEN_COMMA* = 42;
-  TOKEN_PLUS* = 43;
-  TOKEN_MINUS* = 44;
-  TOKEN_MULTIPLICATION* = 45;
-  TOKEN_DIVISION* = 46;
-  TOKEN_REMAINDER* = 47;
-  TOKEN_ASSIGNMENT* = 48;
-  TOKEN_COLON* = 49;
-  TOKEN_HAT* = 50;
-  TOKEN_AT* = 51;
-  TOKEN_COMMENT* = 52;
-  TOKEN_INTEGER* = 53;
-  TOKEN_WORD* = 54;
-  TOKEN_CHARACTER* = 55;
-  TOKEN_STRING* = 56;
-  TOKEN_DEFER* = 57;
-  TOKEN_EXCLAMATION* = 58;
-  TOKEN_ARROW = 59;
-
 type
+  TokenKind* = (
+    unknown,
+    identifier,
+    _if,
+    _then,
+    _else,
+    _elsif,
+    _while,
+    _do,
+    _proc,
+    _begin,
+    _end,
+    _extern,
+    _const,
+    _var,
+    array,
+    _of,
+    _type,
+    _record,
+    _union,
+    pointer,
+    to,
+    boolean,
+    _nil,
+    and,
+    _or,
+    not,
+    _return,
+    _cast,
+    shift_left,
+    shift_right,
+    left_paren,
+    right_paren,
+    left_square,
+    right_square,
+    greater_equal,
+    less_equal,
+    greater_than,
+    less_than,
+    not_equal,
+    equal,
+    semicolon,
+    dot,
+    comma,
+    plus,
+    minus,
+    multiplication,
+    division,
+    remainder,
+    assignment,
+    colon,
+    hat,
+    at,
+    comment,
+    integer,
+    word,
+    character,
+    string,
+    _defer,
+    exclamation,
+    arrow
+  );
   Position* = record
     line: Word;
 	column: Word
@@ -93,7 +95,7 @@ type
 	head: proc(^Byte) -> Char
   end;
   Token* = record
-    kind: Int;
+    kind: TokenKind;
     value: union
       int_value: Int;
       string: String;
@@ -208,12 +210,12 @@ end
 
 proc is_alnum(c: Char) -> Bool;
 begin
-  return is_digit(c) | is_alpha(c)
+  return is_digit(c) or is_alpha(c)
 end
 
 proc is_space(c: Char) -> Bool;
 begin
-  return c = ' ' | c = '\n' | c = '\t'
+  return c = ' ' or c = '\n' or c = '\t'
 end
 
 proc substring(string: String, start: Word, count: Word) -> String;
@@ -413,7 +415,7 @@ end
 
 proc is_ident(char: Char) -> Bool;
 begin
-  return is_alnum(char) | char = '_'
+  return is_alnum(char) or char = '_'
 end
 
 proc lex_identifier(source_code: ^SourceCode, token_content: ^StringBuffer);
@@ -516,137 +518,137 @@ begin
   while i < tokens_size do
     current_token := tokens + i;
 
-    if current_token^.kind = TOKEN_IF then
+    if current_token^.kind = TokenKind._if then
 	  write_s("IF")
-    elsif current_token^.kind = TOKEN_THEN then
+    elsif current_token^.kind = TokenKind._then then
 	  write_s("THEN")
-    elsif current_token^.kind = TOKEN_ELSE then
+    elsif current_token^.kind = TokenKind._else then
 	  write_s("ELSE")
-    elsif current_token^.kind = TOKEN_ELSIF then
+    elsif current_token^.kind = TokenKind._elsif then
 	  write_s("ELSIF")
-    elsif current_token^.kind = TOKEN_WHILE then
+    elsif current_token^.kind = TokenKind._while then
 	  write_s("WHILE")
-    elsif current_token^.kind = TOKEN_DO then
+    elsif current_token^.kind = TokenKind._do then
 	  write_s("DO")
-	elsif current_token^.kind = TOKEN_PROC then
+	elsif current_token^.kind = TokenKind._proc then
 	  write_s("PROC")
-	elsif current_token^.kind = TOKEN_BEGIN then
+	elsif current_token^.kind = TokenKind._begin then
 	  write_s("BEGIN")
-	elsif current_token^.kind = TOKEN_END then
+	elsif current_token^.kind = TokenKind._end then
 	  write_s("END")
-   	elsif current_token^.kind = TOKEN_EXTERN then
+   	elsif current_token^.kind = TokenKind._extern then
 	  write_s("EXTERN")
-	elsif current_token^.kind = TOKEN_CONST then
+	elsif current_token^.kind = TokenKind._const then
 	  write_s("CONST")
-	elsif current_token^.kind = TOKEN_VAR then
+	elsif current_token^.kind = TokenKind._var then
 	  write_s("VAR")
-   	elsif current_token^.kind = TOKEN_ARRAY then
+   	elsif current_token^.kind = TokenKind.array then
 	  write_s("ARRAY")
-	elsif current_token^.kind = TOKEN_OF then
+	elsif current_token^.kind = TokenKind._of then
 	  write_s("OF")
-	elsif current_token^.kind = TOKEN_TYPE then
+	elsif current_token^.kind = TokenKind._type then
 	  write_s("TYPE")
-	elsif current_token^.kind = TOKEN_RECORD then
+	elsif current_token^.kind = TokenKind._record then
 	  write_s("RECORD")
-	elsif current_token^.kind = TOKEN_UNION then
+	elsif current_token^.kind = TokenKind._union then
 	  write_s("UNION")
-	elsif current_token^.kind = TOKEN_POINTER then
+	elsif current_token^.kind = TokenKind.pointer then
 	  write_s("POINTER")
-	elsif current_token^.kind = TOKEN_TO then
+	elsif current_token^.kind = TokenKind.to then
 	  write_s("TO")
-	elsif current_token^.kind = TOKEN_BOOLEAN then
+	elsif current_token^.kind = TokenKind.boolean then
 	  write_s("BOOLEAN<");
 	  write_b(current_token^.value.boolean_value);
 	  write_c('>')
-	elsif current_token^.kind = TOKEN_NIL then
+	elsif current_token^.kind = TokenKind._nil then
 	  write_s("NIL")
-	elsif current_token^.kind = TOKEN_AND then
+	elsif current_token^.kind = TokenKind.and then
 	  write_s("AND")
-	elsif current_token^.kind = TOKEN_OR then
+	elsif current_token^.kind = TokenKind._or then
 	  write_s("OR")
-	elsif current_token^.kind = TOKEN_NOT then
+	elsif current_token^.kind = TokenKind.not then
 	  write_s("NOT")
-	elsif current_token^.kind = TOKEN_RETURN then
+	elsif current_token^.kind = TokenKind._return then
 	  write_s("RETURN")
-	elsif current_token^.kind = TOKEN_CAST then
+	elsif current_token^.kind = TokenKind._cast then
 	  write_s("CAST")
-	elsif current_token^.kind = TOKEN_SHIFT_LEFT then
+	elsif current_token^.kind = TokenKind.shift_left then
 	  write_s("<<")
-	elsif current_token^.kind = TOKEN_SHIFT_RIGHT then
+	elsif current_token^.kind = TokenKind.shift_right then
 	  write_s(">>")
-	elsif current_token^.kind = TOKEN_IDENTIFIER then
+	elsif current_token^.kind = TokenKind.identifier then
 	  write_c('<');
       write_s(current_token^.value.string);
 	  write_c('>')
-	elsif current_token^.kind = TOKEN_LEFT_PAREN then
+	elsif current_token^.kind = TokenKind.left_paren then
 	  write_s("(")
-	elsif current_token^.kind = TOKEN_RIGHT_PAREN then
+	elsif current_token^.kind = TokenKind.right_paren then
 	  write_s(")")
-	elsif current_token^.kind = TOKEN_LEFT_SQUARE then
+	elsif current_token^.kind = TokenKind.left_square then
 	  write_s("[")
-	elsif current_token^.kind = TOKEN_RIGHT_SQUARE then
+	elsif current_token^.kind = TokenKind.right_square then
 	  write_s("]")
-	elsif current_token^.kind = TOKEN_GREATER_EQUAL then
+	elsif current_token^.kind = TokenKind.greater_equal then
 	  write_s(">=")
-	elsif current_token^.kind = TOKEN_LESS_EQUAL then
+	elsif current_token^.kind = TokenKind.less_equal then
 	  write_s("<=")
-	elsif current_token^.kind = TOKEN_GREATER_THAN then
+	elsif current_token^.kind = TokenKind.greater_than then
 	  write_s(">")
-	elsif current_token^.kind = TOKEN_LESS_THAN then
+	elsif current_token^.kind = TokenKind.less_than then
 	  write_s("<")
-	elsif current_token^.kind = TOKEN_EQUAL then
+	elsif current_token^.kind = TokenKind.equal then
 	  write_s("=")
-	elsif current_token^.kind = TOKEN_NOT_EQUAL then
+	elsif current_token^.kind = TokenKind.not_equal then
 	  write_s("<>")
-	elsif current_token^.kind = TOKEN_SEMICOLON then
+	elsif current_token^.kind = TokenKind.semicolon then
 	  write_c(';')
-	elsif current_token^.kind = TOKEN_DOT then
+	elsif current_token^.kind = TokenKind.dot then
 	  write_c('.')
-	elsif current_token^.kind = TOKEN_COMMA then
+	elsif current_token^.kind = TokenKind.comma then
 	  write_c(',')
-	elsif current_token^.kind = TOKEN_PLUS then
+	elsif current_token^.kind = TokenKind.plus then
 	  write_c('+')
-	elsif current_token^.kind = TOKEN_MINUS then
+	elsif current_token^.kind = TokenKind.minus then
 	  write_c('-')
-	elsif current_token^.kind = TOKEN_MULTIPLICATION then
+	elsif current_token^.kind = TokenKind.multiplication then
 	  write_c('*')
-	elsif current_token^.kind = TOKEN_DIVISION then
+	elsif current_token^.kind = TokenKind.division then
 	  write_c('/')
-	elsif current_token^.kind = TOKEN_REMAINDER then
+	elsif current_token^.kind = TokenKind.remainder then
 	  write_c('%')
-	elsif current_token^.kind = TOKEN_ASSIGNMENT then
+	elsif current_token^.kind = TokenKind.assignment then
 	  write_s(":=")
-	elsif current_token^.kind = TOKEN_COLON then
+	elsif current_token^.kind = TokenKind.colon then
 	  write_c(':')
-	elsif current_token^.kind = TOKEN_HAT then
+	elsif current_token^.kind = TokenKind.hat then
 	  write_c('^')
-	elsif current_token^.kind = TOKEN_AT then
+	elsif current_token^.kind = TokenKind.at then
 	  write_c('@')
-	elsif current_token^.kind = TOKEN_COMMENT then
+	elsif current_token^.kind = TokenKind.comment then
 	  write_s("(* COMMENT *)")
-	elsif current_token^.kind = TOKEN_INTEGER then
+	elsif current_token^.kind = TokenKind.integer then
 	  write_c('<');
       write_i(current_token^.value.int_value);
 	  write_c('>')
-	elsif current_token^.kind = TOKEN_WORD then
+	elsif current_token^.kind = TokenKind.word then
 	  write_c('<');
       write_i(current_token^.value.int_value);
 	  write_s("u>")
-	elsif current_token^.kind = TOKEN_CHARACTER then
+	elsif current_token^.kind = TokenKind.character then
 	  write_c('<');
       write_i(cast(current_token^.value.char_value: Int));
 	  write_s("c>")
-	elsif current_token^.kind = TOKEN_STRING then
+	elsif current_token^.kind = TokenKind.string then
 	  write_s("\"...\"")
-	elsif current_token^.kind = TOKEN_DEFER then
+	elsif current_token^.kind = TokenKind._defer then
 	  write_s("DEFER")
-	elsif current_token^.kind = TOKEN_EXCLAMATION then
+	elsif current_token^.kind = TokenKind.exclamation then
 	  write_c('!')
-	elsif current_token^.kind = TOKEN_ARROW then
+	elsif current_token^.kind = TokenKind.arrow then
 	  write_s("->")
 	else
 	  write_s("UNKNOWN<");
-	  write_i(current_token^.kind);
+	  write_i(cast(current_token^.kind: Int));
 	  write_c('>')
 	end;
 	write_c(' ');
@@ -661,65 +663,65 @@ var
   current_token: Token;
 begin
   if "if" = token_content then
-	current_token.kind := TOKEN_IF
+	current_token.kind := TokenKind._if
   elsif "then" = token_content then
-	current_token.kind := TOKEN_THEN
+	current_token.kind := TokenKind._then
   elsif "else" = token_content then
-	current_token.kind := TOKEN_ELSE
+	current_token.kind := TokenKind._else
   elsif "elsif" = token_content then
-	current_token.kind := TOKEN_ELSIF
+	current_token.kind := TokenKind._elsif
   elsif "while" = token_content then
-	current_token.kind := TOKEN_WHILE
+	current_token.kind := TokenKind._while
   elsif "do" = token_content then
-	current_token.kind := TOKEN_DO
+	current_token.kind := TokenKind._do
   elsif "proc" = token_content then
-	current_token.kind := TOKEN_PROC
+	current_token.kind := TokenKind._proc
   elsif "begin" = token_content then
-	current_token.kind := TOKEN_BEGIN
+	current_token.kind := TokenKind._begin
   elsif "end" = token_content then
-	current_token.kind := TOKEN_END
+	current_token.kind := TokenKind._end
   elsif "extern" = token_content then
-	current_token.kind := TOKEN_EXTERN
+	current_token.kind := TokenKind._extern
   elsif "const" = token_content then
-	current_token.kind := TOKEN_CONST
+	current_token.kind := TokenKind._const
   elsif "var" = token_content then
-	current_token.kind := TOKEN_VAR
+	current_token.kind := TokenKind._var
   elsif "array" = token_content then
-	current_token.kind := TOKEN_ARRAY
+	current_token.kind := TokenKind.array
   elsif "of" = token_content then
-	current_token.kind := TOKEN_OF
+	current_token.kind := TokenKind._of
   elsif "type" = token_content then
-	current_token.kind := TOKEN_TYPE
+	current_token.kind := TokenKind._type
   elsif "record" = token_content then
-	current_token.kind := TOKEN_RECORD
+	current_token.kind := TokenKind._record
   elsif "union" = token_content then
-	current_token.kind := TOKEN_UNION
+	current_token.kind := TokenKind._union
   elsif "pointer" = token_content then
-	current_token.kind := TOKEN_POINTER
+	current_token.kind := TokenKind.pointer
   elsif "to" = token_content then
-	current_token.kind := TOKEN_TO
+	current_token.kind := TokenKind.to
   elsif "true" = token_content then
-	current_token.kind := TOKEN_BOOLEAN;
+	current_token.kind := TokenKind.boolean;
 	current_token.value.boolean_value := true
   elsif "false" = token_content then
-	current_token.kind := TOKEN_BOOLEAN;
+	current_token.kind := TokenKind.boolean;
 	current_token.value.boolean_value := false
   elsif "nil" = token_content then
-	current_token.kind := TOKEN_NIL
+	current_token.kind := TokenKind._nil
   elsif "and" = token_content then
-	current_token.kind := TOKEN_AND
+	current_token.kind := TokenKind.and
   elsif "or" = token_content then
-	current_token.kind := TOKEN_OR
+	current_token.kind := TokenKind._or
   elsif "not" = token_content then
-	current_token.kind := TOKEN_NOT
+	current_token.kind := TokenKind.not
   elsif "return" = token_content then
-	current_token.kind := TOKEN_RETURN
+	current_token.kind := TokenKind._return
   elsif "cast" = token_content then
-	current_token.kind := TOKEN_CAST
+	current_token.kind := TokenKind._cast
   elsif "defer" = token_content then
-	current_token.kind := TOKEN_DEFER
+	current_token.kind := TokenKind._defer
   else
-	current_token.kind := TOKEN_IDENTIFIER;
+	current_token.kind := TokenKind.identifier;
 	current_token.value.string := string_dup(token_content)
   end;
 
@@ -743,154 +745,154 @@ begin
     current_token := tokens + tokens_size^;
 	first_char := source_code_head(source_code);
 
-    if is_alpha(first_char) | first_char = '_' then
+    if is_alpha(first_char) or first_char = '_' then
       lex_identifier(@source_code, @token_buffer);
       current_token^ := categorize_identifier(string_buffer_clear(@token_buffer))
 	elsif is_digit(first_char) then
 	  lex_number(@source_code, @current_token^.value.int_value);
 
 	  if source_code_expect(@source_code, 'u') then
-	    current_token^.kind := TOKEN_WORD;
+	    current_token^.kind := TokenKind.word;
         source_code_advance(@source_code)
 	  else
-	    current_token^.kind := TOKEN_INTEGER
+	    current_token^.kind := TokenKind.integer
 	  end
 	elsif first_char = '(' then
 	  source_code_advance(@source_code);
 
 	  if source_code_empty(@source_code) then
-	    current_token^.kind := TOKEN_LEFT_PAREN
+	    current_token^.kind := TokenKind.left_paren
 	  elsif source_code_head(source_code) = '*' then
 	    source_code_advance(@source_code);
 
 		if lex_comment(@source_code, @token_buffer) then
 	      current_token^.value.string := string_dup(string_buffer_clear(@token_buffer));
-		  current_token^.kind := TOKEN_COMMENT
+		  current_token^.kind := TokenKind.comment
 		else
-	      current_token^.kind := 0
+	      current_token^.kind := TokenKind.unknown
 		end
 	  else
-	    current_token^.kind := TOKEN_LEFT_PAREN
+	    current_token^.kind := TokenKind.left_paren
 	  end
 	elsif first_char = ')' then
-	  current_token^.kind := TOKEN_RIGHT_PAREN;
+	  current_token^.kind := TokenKind.right_paren;
 	  source_code_advance(@source_code)
 	elsif first_char = '\'' then
       source_code_advance(@source_code);
 
 	  if lex_character(@source_code, @current_token^.value.char_value) & source_code_expect(@source_code, '\'') then
-	  	current_token^.kind := TOKEN_CHARACTER;
+	  	current_token^.kind := TokenKind.character;
 	    source_code_advance(@source_code)
 	  else
-	    current_token^.kind := 0
+	    current_token^.kind := TokenKind.unknown
 	  end
 	elsif first_char = '"' then
       source_code_advance(@source_code);
 	  
       if lex_string(@source_code, @token_buffer) then
-		current_token^.kind := TOKEN_STRING;
+		current_token^.kind := TokenKind.string;
 		current_token^.value.string := string_dup(string_buffer_clear(@token_buffer))
 	  else
-	    current_token^.kind := 0
+	    current_token^.kind := TokenKind.unknown
 	  end
 	elsif first_char = '[' then
-	  current_token^.kind := TOKEN_LEFT_SQUARE;
+	  current_token^.kind := TokenKind.left_square;
 	  source_code_advance(@source_code)
 	elsif first_char = ']' then
-	  current_token^.kind := TOKEN_RIGHT_SQUARE;
+	  current_token^.kind := TokenKind.right_square;
 	  source_code_advance(@source_code)
 	elsif first_char = '>' then
 	  source_code_advance(@source_code);
 
       if source_code_empty(@source_code) then
-	    current_token^.kind := TOKEN_GREATER_THAN
+	    current_token^.kind := TokenKind.greater_than
 	  elsif source_code_head(source_code) = '=' then
-	    current_token^.kind := TOKEN_GREATER_EQUAL;
+	    current_token^.kind := TokenKind.greater_equal;
 	    source_code_advance(@source_code)
 	  elsif source_code_head(source_code) = '>' then
-	    current_token^.kind := TOKEN_SHIFT_RIGHT;
+	    current_token^.kind := TokenKind.shift_right;
 	    source_code_advance(@source_code)
 	  else
-	    current_token^.kind := TOKEN_GREATER_THAN
+	    current_token^.kind := TokenKind.greater_than
 	  end
 	elsif first_char = '<' then
 	  source_code_advance(@source_code);
 
 	  if source_code_empty(@source_code) then
-	    current_token^.kind := TOKEN_LESS_THAN
+	    current_token^.kind := TokenKind.less_than
 	  elsif source_code_head(source_code) = '=' then
-	    current_token^.kind := TOKEN_LESS_EQUAL;
+	    current_token^.kind := TokenKind.less_equal;
 	    source_code_advance(@source_code)
 	  elsif source_code_head(source_code) = '<' then
-	    current_token^.kind := TOKEN_SHIFT_LEFT;
+	    current_token^.kind := TokenKind.shift_left;
 	    source_code_advance(@source_code)
 	  elsif source_code_head(source_code) = '>' then
-	    current_token^.kind := TOKEN_NOT_EQUAL;
+	    current_token^.kind := TokenKind.not_equal;
 	    source_code_advance(@source_code)
 	  else
-	    current_token^.kind := TOKEN_LESS_THAN
+	    current_token^.kind := TokenKind.less_than
 	  end
 	elsif first_char = '=' then
-	  current_token^.kind := TOKEN_EQUAL;
+	  current_token^.kind := TokenKind.equal;
 	  source_code_advance(@source_code)
 	elsif first_char = ';' then
-	  current_token^.kind := TOKEN_SEMICOLON;
+	  current_token^.kind := TokenKind.semicolon;
 	  source_code_advance(@source_code)
 	elsif first_char = '.' then
-	  current_token^.kind := TOKEN_DOT;
+	  current_token^.kind := TokenKind.dot;
 	  source_code_advance(@source_code)
 	elsif first_char = ',' then
-	  current_token^.kind := TOKEN_COMMA;
+	  current_token^.kind := TokenKind.comma;
 	  source_code_advance(@source_code)
 	elsif first_char = '+' then
-	  current_token^.kind := TOKEN_PLUS;
+	  current_token^.kind := TokenKind.plus;
 	  source_code_advance(@source_code)
 	elsif first_char = '-' then
 	  source_code_advance(@source_code);
 
       if source_code_empty(@source_code) then
-	    current_token^.kind := TOKEN_MINUS
+	    current_token^.kind := TokenKind.minus
 	  elsif source_code_head(source_code) = '>' then
-	    current_token^.kind := TOKEN_ARROW;
+	    current_token^.kind := TokenKind.arrow;
 	    source_code_advance(@source_code)
 	  else
-	    current_token^.kind := TOKEN_MINUS
+	    current_token^.kind := TokenKind.minus
 	  end
 	elsif first_char = '*' then
-	  current_token^.kind := TOKEN_MULTIPLICATION;
+	  current_token^.kind := TokenKind.multiplication;
 	  source_code_advance(@source_code)
 	elsif first_char = '/' then
-	  current_token^.kind := TOKEN_DIVISION;
+	  current_token^.kind := TokenKind.division;
 	  source_code_advance(@source_code)
 	elsif first_char = '%' then
-	  current_token^.kind := TOKEN_REMAINDER;
+	  current_token^.kind := TokenKind.remainder;
 	  source_code_advance(@source_code)
 	elsif first_char = ':' then
 	  source_code_advance(@source_code);
 
 	  if source_code_empty(@source_code) then
-	    current_token^.kind := TOKEN_COLON
+	    current_token^.kind := TokenKind.colon
 	  elsif source_code_head(source_code) = '=' then
-	    current_token^.kind := TOKEN_ASSIGNMENT;
+	    current_token^.kind := TokenKind.assignment;
 	    source_code_advance(@source_code)
 	  else
-	    current_token^.kind := TOKEN_COLON
+	    current_token^.kind := TokenKind.colon
 	  end
 	elsif first_char = '^' then
-	  current_token^.kind := TOKEN_HAT;
+	  current_token^.kind := TokenKind.hat;
 	  source_code_advance(@source_code)
 	elsif first_char = '@' then
-	  current_token^.kind := TOKEN_AT;
+	  current_token^.kind := TokenKind.at;
 	  source_code_advance(@source_code)
 	elsif first_char = '!' then
-	  current_token^.kind := TOKEN_EXCLAMATION;
+	  current_token^.kind := TokenKind.exclamation;
 	  source_code_advance(@source_code)
 	else
-	  current_token^.kind := 0;
+	  current_token^.kind := TokenKind.unknown;
 	  source_code_advance(@source_code)
 	end;
 
-	if current_token^.kind <> 0 then
+	if current_token^.kind <> TokenKind.unknown then
       tokens_size^ := tokens_size^ + 1u;
       skip_spaces(@source_code)
 	else