diff --git a/boot/ast.cc b/boot/ast.cc
index d023b86..0091962 100644
--- a/boot/ast.cc
+++ b/boot/ast.cc
@@ -1012,6 +1012,10 @@ namespace boot
                 return "or";
             case binary_operator::exclusive_disjunction:
                 return "xor";
+            case binary_operator::shift_left:
+                return "<<";
+            case binary_operator::shift_right:
+                return ">>";
         }
         __builtin_unreachable();
     };
diff --git a/boot/lexer.ll b/boot/lexer.ll
index 4fc2664..5837940 100644
--- a/boot/lexer.ll
+++ b/boot/lexer.ll
@@ -137,9 +137,6 @@ return                  {
 cast                    {
                             return yy::parser::make_CAST(this->location);
                         }
-sizeof                  {
-                            return yy::parser::make_SIZEOF(this->location);
-                        }
 defer                   {
                             return yy::parser::make_DEFER(this->location);
                         }
@@ -232,6 +229,12 @@ defer                   {
 \]                      {
                             return yy::parser::make_RIGHT_SQUARE(this->location);
                         }
+\<\<                    {
+                            return yy::parser::make_SHIFT_LEFT(this->location);
+                        }
+\>\>                    {
+                            return yy::parser::make_SHIFT_RIGHT(this->location);
+                        }
 \>=                     {
                             return yy::parser::make_GREATER_EQUAL(this->location);
                         }
diff --git a/boot/parser.yy b/boot/parser.yy
index 9de5c3b..49f3af9 100644
--- a/boot/parser.yy
+++ b/boot/parser.yy
@@ -85,7 +85,7 @@ along with GCC; see the file COPYING3.  If not see
 %token CONST VAR PROCEDURE ARRAY OF TYPE RECORD POINTER TO UNION
 %token BEGIN_BLOCK END_BLOCK EXTERN DEFER
 %token LEFT_PAREN RIGHT_PAREN LEFT_SQUARE RIGHT_SQUARE SEMICOLON DOT COMMA
-%token AND OR NOT CAST SIZEOF
+%token AND OR NOT CAST SHIFT_LEFT SHIFT_RIGHT
 %token GREATER_EQUAL LESS_EQUAL LESS_THAN GREATER_THAN NOT_EQUAL EQUALS
 %token PLUS MINUS MULTIPLICATION DIVISION REMAINDER
 %token ASSIGNMENT COLON HAT AT NIL ARROW
@@ -344,6 +344,16 @@ expression:
             $$ = new elna::boot::binary_expression(elna::boot::make_position(@2), $1, $3,
                 elna::boot::binary_operator::exclusive_disjunction);
         }
+    | expression SHIFT_LEFT expression
+        {
+            $$ = new elna::boot::binary_expression(elna::boot::make_position(@2), $1, $3,
+                elna::boot::binary_operator::shift_left);
+        }
+    | expression SHIFT_RIGHT expression
+        {
+            $$ = new elna::boot::binary_expression(elna::boot::make_position(@2), $1, $3,
+                elna::boot::binary_operator::shift_right);
+        }
 unary:
     AT operand
         {
@@ -448,7 +458,7 @@ variable_declarations:
     | variable_declaration { $$.emplace_back(std::move($1)); }
 variable_part:
     /* no variable declarations */ {}
-    | VAR variable_declarations SEMICOLON { std::swap($$, $2); }
+    | VAR variable_declarations { std::swap($$, $2); }
 constant_definition: identifier_definition EQUALS literal
         {
             $$ = new elna::boot::constant_definition(elna::boot::make_position(@1), $1.first, $1.second, $3);
diff --git a/gcc/elna-generic.cc b/gcc/elna-generic.cc
index 91abf3d..cecfcee 100644
--- a/gcc/elna-generic.cc
+++ b/gcc/elna-generic.cc
@@ -575,10 +575,11 @@ namespace gcc
         }
         if (left_type != right_type
                 && !are_compatible_pointers(left_type, right)
-                && !are_compatible_pointers(right_type, left))
+                && !are_compatible_pointers(right_type, left)
+                && !(is_integral_type(left_type) && right_type == elna_word_type_node))
         {
             error_at(expression_location,
-                    "invalid operands of type %s and %s for operator %s",
+                    "invalid operands of type '%s' and '%s' for operator %s",
                     print_type(left_type).c_str(), print_type(right_type).c_str(),
                     boot::print_binary_operator(expression->operation()));
             this->current_expression = error_mark_node;
@@ -628,6 +629,16 @@ namespace gcc
             case boot::binary_operator::not_equals:
                 this->current_expression = build_equality_operation(expression, left, right);
                 break;
+            case boot::binary_operator::shift_left:
+                this->current_expression = build_binary_operation(
+                        is_numeric_type(left_type) && right_type == elna_word_type_node,
+                        expression, LSHIFT_EXPR, left, right, left_type);
+                break;
+            case boot::binary_operator::shift_right:
+                this->current_expression = build_binary_operation(
+                        is_numeric_type(left_type) && right_type == elna_word_type_node,
+                        expression, RSHIFT_EXPR, left, right, left_type);
+                break;
         }
     }
 
diff --git a/gcc/elna-tree.cc b/gcc/elna-tree.cc
index 2b7bb0a..f36faf7 100644
--- a/gcc/elna-tree.cc
+++ b/gcc/elna-tree.cc
@@ -195,7 +195,7 @@ namespace gcc
         else
         {
             error_at(expression_location,
-                    "invalid operands of type %s and %s for operator %s",
+                    "invalid operands of type '%s' and '%s' for operator %s",
                     print_type(left_type).c_str(), print_type(right_type).c_str(),
                     elna::boot::print_binary_operator(expression->operation()));
             return error_mark_node;
diff --git a/include/elna/boot/ast.h b/include/elna/boot/ast.h
index 10800d2..06054e5 100644
--- a/include/elna/boot/ast.h
+++ b/include/elna/boot/ast.h
@@ -42,7 +42,9 @@ namespace boot
         greater_equal,
         disjunction,
         conjunction,
-        exclusive_disjunction
+        exclusive_disjunction,
+        shift_left,
+        shift_right
     };
 
     enum class unary_operator
diff --git a/source.elna b/source.elna
index 5c4df3c..3868369 100644
--- a/source.elna
+++ b/source.elna
@@ -173,7 +173,7 @@ end
 proc write_i(value: Int);
 var
   digit: Int, n: Word,
-  buffer: array 10 of Char;
+  buffer: array 10 of Char
 begin
   n := 10u;
 
@@ -230,7 +230,7 @@ end
 
 proc string_dup(origin: String) -> String;
 var
-  copy: pointer to Char;
+  copy: pointer to Char
 begin
   copy := cast(malloc(origin.length): pointer to Char);
   strncpy(copy, origin.ptr, origin.length);
@@ -244,7 +244,7 @@ end
 
 proc make_position() -> Position;
 var
-  result: Position;
+  result: Position
 begin
   return Position(1u, 1u)
 end
@@ -253,7 +253,7 @@ proc read_source(filename: pointer to Char, result: pointer to String) -> Bool;
 var
   input_file: pointer to FILE,
   source_size: Int,
-  input: pointer to Byte;
+  input: pointer to Byte
 begin
   input_file := fopen(filename, "rb\0".ptr);
 
@@ -349,7 +349,7 @@ end
 
 proc lex_identifier(source_code: pointer to SourceCode, token_content: pointer to String);
 var
-  content_length: Word;
+  content_length: Word
 begin
   content_length := 0u;
   token_content^ := source_code^.text;
@@ -363,7 +363,7 @@ end
 
 proc lex_comment(source_code: pointer to SourceCode, token_content: pointer to String) -> Bool;
 var
-  content_length: Word;
+  content_length: Word
 begin
   content_length := 0u;
   token_content^ := source_code^.text;
@@ -401,7 +401,7 @@ var
   token_end: pointer to Char,
   constructed_string: pointer to Char,
   token_length: Word,
-  is_valid: Bool;
+  is_valid: Bool
 begin
   token_end := input;
 
@@ -439,7 +439,7 @@ end
 proc print_tokens(tokens: pointer to Token, tokens_size: Word);
 var
   current_token: pointer to Token,
-  i: Word;
+  i: Word
 begin
   i := 0u;
   while i < tokens_size do
@@ -583,7 +583,7 @@ end
 
 proc categorize_identifier(token_content: String) -> Token;
 var
-  current_token: Token;
+  current_token: Token
 begin
   if "if" = token_content then
 	current_token.kind := TOKEN_IF
@@ -662,7 +662,7 @@ var
   current_token: pointer to Token,
   token_length: Word,
   first_char: Char,
-  token_content: String;
+  token_content: String
 begin
   tokens_size^ := 0u;
   tokens := nil;
@@ -827,7 +827,7 @@ end
 proc parse_constant_definition(tokens: pointer to pointer to Token,
     tokens_size: pointer to Word) -> pointer to ConstantDefinition;
 var
-  result: pointer to ConstantDefinition;
+  result: pointer to ConstantDefinition
 begin
   result := cast(calloc(1u, ConstantDefinition.size): pointer to ConstantDefinition);
 
@@ -851,7 +851,7 @@ end
 proc parse_program(tokens: pointer to pointer to Token, tokens_size: pointer to Word) -> pointer to Program;
 var
   result: pointer to Program,
-  current_constant: pointer to pointer to ConstantDefinition;
+  current_constant: pointer to pointer to ConstantDefinition
 begin
   result := cast(calloc(1u, Program.size): pointer to Program);
 
@@ -885,7 +885,7 @@ proc parse_command_line*(argc: Int, argv: pointer to pointer to Char) -> pointer
 var
   parameter: pointer to pointer to Char,
   i: Int,
-  result: pointer to CommandLine;
+  result: pointer to CommandLine
 begin
   i := 1;
   result := cast(malloc(CommandLine.size): pointer to CommandLine);
@@ -927,7 +927,7 @@ var
   tokens: pointer to Token,
   tokens_size: Word,
   source_code: SourceCode,
-  command_line: pointer to CommandLine;
+  command_line: pointer to CommandLine
 begin
   command_line := parse_command_line(argc, argv);
   if command_line = nil then