diff --git a/Rakefile b/Rakefile
index 774a3e7..ba6063a 100644
--- a/Rakefile
+++ b/Rakefile
@@ -44,11 +44,12 @@ end
       .partition { |f| f.end_with? '.elna' }
 
     File.open t.name, 'w' do |output|
-      puts
-      puts(compiler * ' ')
+      compiler_command = compiler + sources
 
-      Open3.popen2(*compiler) do |cl_in, cl_out|
-        cl_in.write File.read(*sources)
+      puts
+      puts(compiler_command * ' ')
+
+      Open3.popen2(*compiler_command) do |cl_in, cl_out|
         cl_in.close
 
         IO.copy_stream cl_out, output
@@ -87,11 +88,11 @@ task default: 'source/Compiler.elna'
 task :default do |t|
   exe, previous_output, source = t.prerequisites
 
-  cat_arguments = ['cat', source]
+  exe_arguments = [exe, source]
   diff_arguments = ['diff', '-Nur', '--text', previous_output, '-']
 
-  puts [cat_arguments * ' ', exe, diff_arguments * ' '].join(' | ')
-  Open3.pipeline(cat_arguments, exe, diff_arguments)
+  puts [exe, diff_arguments * ' '].join(' | ')
+  Open3.pipeline exe_arguments, diff_arguments
 end
 
 task :backport do
@@ -104,7 +105,7 @@ task :backport do
     source
       .gsub(/^(var|type|const|begin)/) { |match| match.upcase }
       .gsub(/^[[:alnum:]]* ?module/) { |match| match.upcase }
-      .gsub(/\b(record|nil|or)\b/) { |match| match.upcase }
+      .gsub(/\b(record|nil|or|false|true)\b/) { |match| match.upcase }
       .gsub(/proc\(/, 'PROCEDURE(')
       .gsub(/ & /, ' AND ')
       .gsub(/ -> /, ': ')
diff --git a/source/CommandLineInterface.def b/source/CommandLineInterface.def
new file mode 100644
index 0000000..85be324
--- /dev/null
+++ b/source/CommandLineInterface.def
@@ -0,0 +1,15 @@
+DEFINITION MODULE CommandLineInterface;
+
+FROM Common IMPORT ShortString;
+
+TYPE
+  CommandLine = RECORD
+    input: ShortString;
+    lex: BOOLEAN;
+    parse: BOOLEAN
+  END;
+  PCommandLine = POINTER TO CommandLine;
+
+PROCEDURE parse_command_line(): PCommandLine;
+
+END CommandLineInterface.
diff --git a/source/CommandLineInterface.elna b/source/CommandLineInterface.elna
new file mode 100644
index 0000000..eb16b4f
--- /dev/null
+++ b/source/CommandLineInterface.elna
@@ -0,0 +1,75 @@
+implementation module CommandLineInterface;
+
+from SYSTEM import ADR, TSIZE;
+
+from Args import GetArg, Narg;
+from FIO import WriteString, WriteChar, WriteLine, StdErr;
+from Storage import ALLOCATE;
+from Strings import CompareStr, Length;
+from MemUtils import MemZero;
+
+from Common import ShortString;
+
+proc parse_command_line() -> PCommandLine;
+var
+  parameter: ShortString;
+  i: CARDINAL;
+  result: PCommandLine;
+  parsed: BOOLEAN;
+begin
+  i := 1;
+  ALLOCATE(result, TSIZE(CommandLine));
+  result^.lex := false;
+  result^.parse := false;
+  MemZero(ADR(result^.input), 256);
+
+  while (i < Narg()) & (result <> nil) do
+    parsed := GetArg(parameter, i);
+    parsed := false;
+
+    if CompareStr(parameter, '--lex') = 0 then
+      parsed := true;
+      result^.lex := true
+    end;
+    if CompareStr(parameter, '--parse') = 0 then
+      parsed := true;
+      result^.parse := true
+    end;
+    if parameter[0] <> '-' then
+      parsed := true;
+
+      if Length(result^.input) > 0 then
+        WriteString(StdErr, 'Fatal error: only one source file can be compiled at once. First given "');
+        WriteString(StdErr, result^.input);
+        WriteString(StdErr, '", then "');
+        WriteString(StdErr, parameter);
+        WriteString(StdErr, '".');
+        WriteLine(StdErr);
+        result := nil
+      end;
+      if result <> nil then
+        result^.input := parameter
+      end
+    end;
+    if parsed = false then
+      WriteString(StdErr, 'Fatal error: unknown command line options: ');
+
+      WriteString(StdErr, parameter);
+      WriteChar(StdErr, '.');
+      WriteLine(StdErr);
+
+      result := nil
+    end;
+
+    i := i + 1
+  end;
+  if (result <> nil) & (Length(result^.input) = 0) then
+    WriteString(StdErr, 'Fatal error: no input files.');
+    WriteLine(StdErr);
+    result := nil
+  end;
+
+  return result
+end;
+
+end CommandLineInterface.
diff --git a/source/Common.def b/source/Common.def
new file mode 100644
index 0000000..c6f661d
--- /dev/null
+++ b/source/Common.def
@@ -0,0 +1,8 @@
+DEFINITION MODULE Common;
+
+TYPE
+  ShortString = ARRAY[0..255] OF CHAR;
+  Identifier = ARRAY[1..256] OF CHAR;
+  PIdentifier = POINTER TO Identifier;
+
+END Common.
diff --git a/source/Common.elna b/source/Common.elna
new file mode 100644
index 0000000..7b8d623
--- /dev/null
+++ b/source/Common.elna
@@ -0,0 +1,3 @@
+implementation module Common;
+
+end Common.
diff --git a/source/Compiler.elna b/source/Compiler.elna
index 4e6ea19..b5f85a5 100644
--- a/source/Compiler.elna
+++ b/source/Compiler.elna
@@ -1,18 +1,51 @@
 module Compiler;
 
-from FIO import StdIn;
+from FIO import Close, IsNoError, File, OpenToRead, StdErr, StdOut, WriteLine, WriteString;
 from SYSTEM import ADR;
+from M2RTS import HALT, ExitOnHalt;
 
 from Lexer import Lexer, lexer_destroy, lexer_initialize;
 from Transpiler import transpile;
+from CommandLineInterface import PCommandLine, parse_command_line;
 
+var
+  command_line: PCommandLine;
+
+proc compile_from_stream();
 var
   lexer: Lexer;
+  source_input: File;
+begin
+  source_input := OpenToRead(command_line^.input);
+
+  if IsNoError(source_input) = false then
+    WriteString(StdErr, 'Fatal error: failed to read the input file "');
+    WriteString(StdErr, command_line^.input);
+    WriteString(StdErr, '".');
+    WriteLine(StdErr);
+
+    ExitOnHalt(2)
+  end;
+  if IsNoError(source_input) then
+    lexer_initialize(ADR(lexer), source_input);
+
+    transpile(ADR(lexer), StdOut);
+
+    lexer_destroy(ADR(lexer));
+
+    Close(source_input)
+  end
+end;
 
 begin
-  lexer_initialize(ADR(lexer), StdIn);
+  ExitOnHalt(0);
+  command_line := parse_command_line();
 
-  transpile(ADR(lexer));
-
-  lexer_destroy(ADR(lexer))
+  if command_line <> nil then
+    compile_from_stream()
+  end;
+  if command_line = nil then
+    ExitOnHalt(1)
+  end;
+  HALT()
 end Compiler.
diff --git a/source/Lexer.def b/source/Lexer.def
index 0df33cd..68643f8 100644
--- a/source/Lexer.def
+++ b/source/Lexer.def
@@ -2,6 +2,8 @@ DEFINITION MODULE Lexer;
 
 FROM FIO IMPORT File;
 
+FROM Common IMPORT Identifier;
+
 TYPE
   PLexerBuffer = POINTER TO CHAR;
   Lexer = RECORD
@@ -81,7 +83,7 @@ TYPE
   LexerToken = RECORD
     CASE kind: LexerKind OF
       lexerKindBoolean: booleanKind: BOOLEAN |
-      lexerKindIdentifier: identifierKind: ARRAY[1..256] OF CHAR
+      lexerKindIdentifier: identifierKind: Identifier
     END
   END;
   PLexerToken = POINTER TO LexerToken;
diff --git a/source/Lexer.elna b/source/Lexer.elna
index 902e93a..19cfd34 100644
--- a/source/Lexer.elna
+++ b/source/Lexer.elna
@@ -217,7 +217,7 @@ var
   index: CARDINAL;
 begin
   index := 0;
-  result := TRUE;
+  result := true;
 
   while (index < Length(Keyword)) & (TokenStart <> TokenEnd) & result DO
     result := (Keyword[index] = TokenStart^) or (Lower(Keyword[index]) = TokenStart^);
@@ -409,11 +409,11 @@ begin
   end;
   if compare_keyword('TRUE', lexer^.Start, lexer^.Current) then
     token^.kind := lexerKindBoolean;
-    token^.booleanKind := TRUE
+    token^.booleanKind := true
   end;
   if compare_keyword('FALSE', lexer^.Start, lexer^.Current) then
     token^.kind := lexerKindBoolean;
-    token^.booleanKind := FALSE
+    token^.booleanKind := false
   end
 end;
 
diff --git a/source/Parser.def b/source/Parser.def
new file mode 100644
index 0000000..d4fe66e
--- /dev/null
+++ b/source/Parser.def
@@ -0,0 +1,46 @@
+DEFINITION MODULE Parser;
+
+FROM Common IMPORT Identifier, PIdentifier;
+
+TYPE
+  AstConstantDeclaration = RECORD
+  END;
+  PAstConstantDeclaration = POINTER TO AstConstantDeclaration;
+  PPAstConstantDeclaration = POINTER TO PAstConstantDeclaration;
+
+  AstTypeExpressionKind = (
+    astTypeExpressionKindNamed,
+    astTypeExpressionKindRecord,
+    astTypeExpressionKindEnumeration,
+    astTypeExpressionKindArray,
+    astTypeExpressionKindPointer,
+    astTypeExpressionKindProcedure
+  );
+  AstTypeExpression = RECORD
+    CASE kind: AstTypeExpressionKind OF
+      astTypeExpressionKindNamed: name: Identifier |
+      astTypeExpressionKindEnumeration: cases: PIdentifier
+    END
+  END;
+  PAstTypeExpression = POINTER TO AstTypeExpression;
+
+  AstTypeDeclaration = RECORD
+    identifier: Identifier;
+    type_expression: PAstTypeExpression
+  END;
+  PAstTypeDeclaration = POINTER TO AstTypeDeclaration;
+  PPAstTypeDeclaration = POINTER TO PAstTypeDeclaration;
+
+  AstVariableDeclaration = RECORD
+  END;
+  PAstVariableDeclaration = POINTER TO AstVariableDeclaration;
+  PPAstVariableDeclaration = POINTER TO PAstVariableDeclaration;
+
+  AstModule = RECORD
+    constants: PPAstConstantDeclaration;
+    types: PPAstTypeDeclaration;
+    variables: PPAstVariableDeclaration
+  END;
+  PAstModule = POINTER TO AstModule;
+
+END Parser.
diff --git a/source/Parser.elna b/source/Parser.elna
new file mode 100644
index 0000000..d4d55ed
--- /dev/null
+++ b/source/Parser.elna
@@ -0,0 +1,3 @@
+implementation module Parser;
+
+end Parser.
diff --git a/source/Transpiler.def b/source/Transpiler.def
index c3cd8a7..555a960 100644
--- a/source/Transpiler.def
+++ b/source/Transpiler.def
@@ -1,7 +1,17 @@
 DEFINITION MODULE Transpiler;
 
-FROM Lexer IMPORT PLexer;
+FROM FIO IMPORT File;
 
-PROCEDURE transpile(ALexer: PLexer);
+FROM Lexer IMPORT PLexer, Lexer;
+
+TYPE
+  TranspilerContext = RECORD
+    indentation: CARDINAL;
+    output: File;
+    lexer: PLexer
+  END;
+  PTranspilerContext = POINTER TO TranspilerContext;
+
+PROCEDURE transpile(lexer: PLexer; output: File);
 
 END Transpiler.
diff --git a/source/Transpiler.elna b/source/Transpiler.elna
index 9820193..373a18a 100644
--- a/source/Transpiler.elna
+++ b/source/Transpiler.elna
@@ -1,16 +1,18 @@
 implementation module Transpiler;
 
-from FIO import WriteNBytes, StdOut;
-from SYSTEM import ADR, ADDRESS;
+from FIO import WriteNBytes, WriteLine, WriteChar, WriteString;
+from SYSTEM import ADR, ADDRESS, TSIZE;
 
-from Terminal import Write, WriteLn, WriteString;
+from Storage import ALLOCATE, REALLOCATE;
+from MemUtils import MemCopy, MemZero;
+
+from Common import Identifier, PIdentifier;
 from Lexer import Lexer, LexerToken, lexer_current, lexer_lex, LexerKind;
-
-type
-  PTranspilerContext = ^TranspilerContext;
-  TranspilerContext = record
-    Indentation: CARDINAL
-  end;
+from Parser import AstModule, PAstModule, AstTypeExpressionKind,
+  AstConstantDeclaration, PPAstConstantDeclaration,
+  AstTypeDeclaration, PAstTypeDeclaration, PPAstTypeDeclaration,
+  AstVariableDeclaration, PPAstVariableDeclaration,
+  PAstTypeExpression, AstTypeExpression;
 
 (* Calls lexer_lex() but skips the comments. *)
 proc transpiler_lex(lexer: PLexer) -> LexerToken;
@@ -27,643 +29,740 @@ begin
 end;
 
 (* Write a semicolon followed by a newline. *)
-proc write_semicolon();
+proc write_semicolon(output: File);
 begin
-  WriteString(';');
-  WriteLn()
+  WriteChar(output, ';');
+  WriteLine(output)
 end;
 
-proc transpile_import(context: PTranspilerContext,  lexer: PLexer);
+proc write_current(lexer: PLexer, output: File);
 var
-  token: LexerToken;
   written_bytes: CARDINAL;
 begin
-  WriteString('FROM ');
-  token := transpiler_lex(lexer);
-
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-
-  token := transpiler_lex(lexer);
-  WriteString(' IMPORT ');
-
-  token := transpiler_lex(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-
-  token := transpiler_lex(lexer);
-  while token.kind <> lexerKindSemicolon do
-    WriteString(', ');
-    token := transpiler_lex(lexer);
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-    token := transpiler_lex(lexer)
-  end;
-  write_semicolon();
-  token := transpiler_lex(lexer)
+  written_bytes := WriteNBytes(output, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start)
 end;
 
-proc transpile_import_part(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_import(context: PTranspilerContext);
 var
   token: LexerToken;
 begin
-  token := lexer_current(lexer);
+  WriteString(context^.output, 'FROM ');
+  token := transpiler_lex(context^.lexer);
+
+  write_current(context^.lexer, context^.output);
+  token := transpiler_lex(context^.lexer);
+  WriteString(context^.output, ' IMPORT ');
+
+  token := transpiler_lex(context^.lexer);
+  write_current(context^.lexer, context^.output);
+
+  token := transpiler_lex(context^.lexer);
+  while token.kind <> lexerKindSemicolon do
+    WriteString(context^.output, ', ');
+    token := transpiler_lex(context^.lexer);
+    write_current(context^.lexer, context^.output);
+    token := transpiler_lex(context^.lexer)
+  end;
+  write_semicolon(context^.output);
+  token := transpiler_lex(context^.lexer)
+end;
+
+proc transpile_import_part(context: PTranspilerContext);
+var
+  token: LexerToken;
+begin
+  token := lexer_current(context^.lexer);
 
   while token.kind = lexerKindFrom do
-    transpile_import(context, lexer);
-    token := lexer_current(lexer)
+    transpile_import(context);
+    token := lexer_current(context^.lexer)
   end;
-  WriteLn()
+  WriteLine(context^.output)
 end;
 
-proc transpile_constant(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_constant(context: PTranspilerContext);
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
 begin
-  WriteString('  ');
-  token := lexer_current(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
+  WriteString(context^.output, '  ');
+  token := lexer_current(context^.lexer);
+  write_current(context^.lexer, context^.output);
 
-  token := transpiler_lex(lexer);
-  WriteString(' = ');
+  token := transpiler_lex(context^.lexer);
+  WriteString(context^.output, ' = ');
 
-  token := transpiler_lex(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
+  token := transpiler_lex(context^.lexer);
+  write_current(context^.lexer, context^.output);
 
-  token := transpiler_lex(lexer);
-  write_semicolon()
+  token := transpiler_lex(context^.lexer);
+  write_semicolon(context^.output)
 end;
 
-proc transpile_constant_part(context: PTranspilerContext,  lexer: PLexer) -> BOOLEAN;
+proc transpile_constant_part(context: PTranspilerContext) -> PPAstConstantDeclaration;
 var
   token: LexerToken;
-  result: BOOLEAN;
 begin
-  token := lexer_current(lexer);
-  result := token.kind = lexerKindConst;
+  token := lexer_current(context^.lexer);
 
-  if result then
-    WriteString('CONST');
-    WriteLn();
-    token := transpiler_lex(lexer);
+  if token.kind = lexerKindConst then
+    WriteString(context^.output, 'CONST');
+    WriteLine(context^.output);
+    token := transpiler_lex(context^.lexer);
 
     while token.kind = lexerKindIdentifier do
-      transpile_constant(context, lexer);
-      token := transpiler_lex(lexer)
+      transpile_constant(context);
+      token := transpiler_lex(context^.lexer)
     end
   end;
-  return result
+  return nil
 end;
 
-proc transpile_module(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_module(context: PTranspilerContext) -> PAstModule;
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
+  result: PAstModule;
 begin
-  token := transpiler_lex(lexer);
+  ALLOCATE(result, TSIZE(AstModule));
+  token := transpiler_lex(context^.lexer);
 
   if token.kind = lexerKindDefinition then
-    WriteString('DEFINITION ');
-    token := transpiler_lex(lexer)
+    WriteString(context^.output, 'DEFINITION ');
+    token := transpiler_lex(context^.lexer)
   end;
   if token.kind = lexerKindImplementation then
-    WriteString('IMPLEMENTATION ');
-    token := transpiler_lex(lexer)
+    WriteString(context^.output, 'IMPLEMENTATION ');
+    token := transpiler_lex(context^.lexer)
   end;
-  WriteString('MODULE ');
+  WriteString(context^.output, 'MODULE ');
 
   (* Write the module name and end the line with a semicolon and newline. *)
-  token := transpiler_lex(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
+  token := transpiler_lex(context^.lexer);
+  write_current(context^.lexer, context^.output);
 
-  token := transpiler_lex(lexer);
-  write_semicolon();
-  WriteLn();
+  token := transpiler_lex(context^.lexer);
+  write_semicolon(context^.output);
+  WriteLine(context^.output);
 
   (* Write the module body. *)
-  token := transpiler_lex(lexer);
-  transpile_import_part(context, lexer);
-  if transpile_constant_part(context, lexer) then
-    WriteLn()
-  end;
-  transpile_type_part(context, lexer);
-  if transpile_variable_part(context, lexer) then
-    WriteLn()
-  end;
-  transpile_procedure_part(context, lexer);
-  transpile_statement_part(context, lexer);
+  token := transpiler_lex(context^.lexer);
+  transpile_import_part(context);
 
-  WriteString('END ');
+  result^.constants := transpile_constant_part(context);
+  result^.types := transpile_type_part(context);
+  result^.variables := transpile_variable_part(context);
 
-  token := transpiler_lex(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
+  transpile_procedure_part(context);
+  transpile_statement_part(context);
 
-  token := transpiler_lex(lexer);
-  Write('.');
+  WriteString(context^.output, 'END ');
 
-  token := transpiler_lex(lexer);
-  WriteLn()
+  token := transpiler_lex(context^.lexer);
+  write_current(context^.lexer, context^.output);
+
+  token := transpiler_lex(context^.lexer);
+  WriteChar(context^.output, '.');
+
+  token := transpiler_lex(context^.lexer);
+  WriteLine(context^.output);
+
+  return result
 end;
 
-proc transpile_type_fields(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_type_fields(context: PTranspilerContext);
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
+  type_expression: PAstTypeExpression;
 begin
-  token := transpiler_lex(lexer);
+  token := transpiler_lex(context^.lexer);
 
   while token.kind <> lexerKindEnd do
-    WriteString('    ');
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-    token := transpiler_lex(lexer);
-    WriteString(': ');
-    transpile_type_expression(context, lexer);
-    token := transpiler_lex(lexer);
+    WriteString(context^.output, '    ');
+    write_current(context^.lexer, context^.output);
+    token := transpiler_lex(context^.lexer);
+    WriteString(context^.output, ': ');
+    type_expression := transpile_type_expression(context);
+    token := transpiler_lex(context^.lexer);
 
     if token.kind = lexerKindSemicolon then
-      token := transpiler_lex(lexer);
-      Write(';')
+      token := transpiler_lex(context^.lexer);
+      WriteChar(context^.output, ';')
     end;
-    WriteLn()
+    WriteLine(context^.output)
   end
 end;
 
-proc transpile_record_type(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_record_type(context: PTranspilerContext) -> PAstTypeExpression;
 var
-  token: LexerToken;
+  result: PAstTypeExpression;
 begin
-  WriteString('RECORD');
-  WriteLn();
-  transpile_type_fields(context, lexer);
-  WriteString('  END')
+  ALLOCATE(result, TSIZE(AstTypeExpression));
+  result^.kind := astTypeExpressionKindRecord;
+
+  WriteString(context^.output, 'RECORD');
+  WriteLine(context^.output);
+  transpile_type_fields(context);
+  WriteString(context^.output, '  END');
+
+  return result
 end;
 
-proc transpile_pointer_type(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_pointer_type(context: PTranspilerContext) -> PAstTypeExpression;
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
+  type_expression: PAstTypeExpression;
+  result: PAstTypeExpression;
 begin
-  token := lexer_current(lexer);
-  WriteString('POINTER TO ');
+  ALLOCATE(result, TSIZE(AstTypeExpression));
+  result^.kind := astTypeExpressionKindPointer;
+
+  token := lexer_current(context^.lexer);
+  WriteString(context^.output, 'POINTER TO ');
   if token.kind = lexerKindPointer then
-    token := transpiler_lex(lexer)
+    token := transpiler_lex(context^.lexer)
   end;
-  transpile_type_expression(context, lexer)
+  type_expression := transpile_type_expression(context);
+
+  return result
 end;
 
-proc transpile_array_type(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_array_type(context: PTranspilerContext) -> PAstTypeExpression;
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
+  type_expression: PAstTypeExpression;
+  result: PAstTypeExpression;
 begin
-  WriteString('ARRAY');
-  token := lexer_current(lexer);
+  ALLOCATE(result, TSIZE(AstTypeExpression));
+  result^.kind := astTypeExpressionKindArray;
+
+  WriteString(context^.output, 'ARRAY');
+  token := lexer_current(context^.lexer);
 
   if token.kind = lexerKindArray then
-    token := transpiler_lex(lexer)
+    token := transpiler_lex(context^.lexer)
   end;
   if token.kind <> lexerKindOf then
-    WriteString('[1..');
-    token := transpiler_lex(lexer);
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-    token := transpiler_lex(lexer);
-    Write(']')
+    WriteString(context^.output, '[1..');
+    token := transpiler_lex(context^.lexer);
+    write_current(context^.lexer, context^.output);
+    token := transpiler_lex(context^.lexer);
+    WriteChar(context^.output, ']')
   end;
-  WriteString(' OF ');
-  transpile_type_expression(context, lexer)
+  WriteString(context^.output, ' OF ');
+  type_expression := transpile_type_expression(context);
+
+  return result
 end;
 
-proc transpile_enumeration_type(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_enumeration_type(context: PTranspilerContext) -> PAstTypeExpression;
 var
   token: LexerToken;
+  result: PAstTypeExpression;
+  current_case: PIdentifier;
+  case_count: CARDINAL;
   written_bytes: CARDINAL;
 begin
-  WriteString('(');
-  WriteLn();
-  WriteString('    ');
+  ALLOCATE(result, TSIZE(AstTypeExpression));
+  result^.kind := astTypeExpressionKindEnumeration;
 
-  token := transpiler_lex(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
+  case_count := 1;
+  ALLOCATE(result^.cases, TSIZE(Identifier) * 2);
+  token := transpiler_lex(context^.lexer);
+  current_case := result^.cases;
+  current_case^ := token.identifierKind;
 
-  token := transpiler_lex(lexer);
+  token := transpiler_lex(context^.lexer);
 
   while token.kind = lexerKindComma do
-    Write(',');
-    WriteLn();
-    WriteString('    ');
-    token := transpiler_lex(lexer);
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
+    token := transpiler_lex(context^.lexer);
 
-    token := transpiler_lex(lexer)
+    INC(case_count);
+    REALLOCATE(result^.cases, TSIZE(Identifier) * (case_count + 1));
+    current_case := result^.cases;
+	INC(current_case, TSIZE(Identifier) * (case_count - 1));
+	current_case^ := token.identifierKind;
+
+    token := transpiler_lex(context^.lexer)
   end;
-  WriteLn();
-  WriteString('  )')
+  INC(current_case, TSIZE(Identifier));
+  MemZero(current_case, TSIZE(Identifier));
+
+  (* Write the cases using the generated identifier list before. *)
+  current_case := result^.cases;
+
+  WriteString(context^.output, '(');
+  WriteLine(context^.output);
+  WriteString(context^.output, '    ');
+  written_bytes := WriteNBytes(context^.output, ORD(current_case^[1]), ADR(current_case^[2]));
+  INC(current_case, TSIZE(Identifier));
+
+  while ORD(current_case^[1]) <> 0 do
+    WriteChar(context^.output, ',');
+    WriteLine(context^.output);
+    WriteString(context^.output, '    ');
+    written_bytes := WriteNBytes(context^.output, ORD(current_case^[1]), ADR(current_case^[2]));
+
+    INC(current_case, TSIZE(Identifier))
+  end;
+  WriteLine(context^.output);
+  WriteString(context^.output, '  )');
+
+  return result
 end;
 
-proc transpile_union_type(context: PTranspilerContext,  lexer: PLexer);
-var
-  token: LexerToken;
-end;
-
-proc transpile_procedure_type(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_named_type(context: PTranspilerContext) -> PAstTypeExpression;
 var
   token: LexerToken;
+  result: PAstTypeExpression;
   written_bytes: CARDINAL;
 begin
-  token := transpiler_lex(lexer);
-  WriteString('PROCEDURE(');
+  token := lexer_current(context^.lexer);
+  ALLOCATE(result, TSIZE(AstTypeExpression));
 
-  token := transpiler_lex(lexer);
+  result^.kind := astTypeExpressionKindNamed;
+  result^.name := token.identifierKind;
+
+  written_bytes := WriteNBytes(context^.output, ORD(result^.name[1]), ADR(result^.name[2]));
+
+  return result
+end;
+
+proc transpile_procedure_type(context: PTranspilerContext) -> PAstTypeExpression;
+var
+  token: LexerToken;
+  result: PAstTypeExpression;
+begin
+  ALLOCATE(result, TSIZE(AstTypeExpression));
+  result^.kind := astTypeExpressionKindProcedure;
+
+  token := transpiler_lex(context^.lexer);
+  WriteString(context^.output, 'PROCEDURE(');
+
+  token := transpiler_lex(context^.lexer);
 
   while token.kind <> lexerKindRightParen do
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
+    write_current(context^.lexer, context^.output);
 
-    token := transpiler_lex(lexer);
+    token := transpiler_lex(context^.lexer);
     if token.kind = lexerKindComma then
-      token := transpiler_lex(lexer);
-      WriteString(', ')
+      token := transpiler_lex(context^.lexer);
+      WriteString(context^.output, ', ')
     end
   end;
-  Write(')')
+  WriteChar(context^.output, ')');
+
+  return nil
 end;
 
-proc transpile_type_expression(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_type_expression(context: PTranspilerContext) -> PAstTypeExpression;
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
+  result: PAstTypeExpression;
 begin
-  token := transpiler_lex(lexer);
+  result := nil;
+  token := transpiler_lex(context^.lexer);
+
   if token.kind = lexerKindRecord then
-    transpile_record_type(context, lexer)
+    result := transpile_record_type(context)
   end;
   if token.kind = lexerKindLeftParen then
-    transpile_enumeration_type(context, lexer)
+    result := transpile_enumeration_type(context)
   end;
   if (token.kind = lexerKindArray) or (token.kind = lexerKindLeftSquare) then
-    transpile_array_type(context, lexer)
+    result := transpile_array_type(context)
   end;
   if token.kind = lexerKindHat then
-    transpile_pointer_type(context, lexer)
+    result := transpile_pointer_type(context)
   end;
   if token.kind = lexerKindProc then
-    transpile_procedure_type(context, lexer)
+    result := transpile_procedure_type(context)
   end;
   if token.kind = lexerKindIdentifier then
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start)
-  end
-end;
-
-proc transpile_type_declaration(context: PTranspilerContext,  lexer: PLexer);
-var
-  token: LexerToken;
-  written_bytes: CARDINAL;
-begin
-  WriteString('  ');
-  token := lexer_current(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-
-  token := transpiler_lex(lexer);
-  WriteString(' = ');
-  transpile_type_expression(context, lexer);
-  token := transpiler_lex(lexer);
-  write_semicolon();
-end;
-
-proc transpile_type_part(context: PTranspilerContext,  lexer: PLexer);
-var
-  token: LexerToken;
-begin
-  token := lexer_current(lexer);
-
-  if token.kind = lexerKindType then
-    WriteString('TYPE');
-    WriteLn();
-    token := transpiler_lex(lexer);
-
-    while token.kind = lexerKindIdentifier do
-      transpile_type_declaration(context, lexer);
-      token := transpiler_lex(lexer)
-    end;
-    WriteLn()
-  end
-end;
-
-proc transpile_variable_declaration(context: PTranspilerContext,  lexer: PLexer);
-var
-  token: LexerToken;
-  written_bytes: CARDINAL;
-begin
-  WriteString('  ');
-  token := lexer_current(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-
-  token := transpiler_lex(lexer);
-  WriteString(': ');
-  transpile_type_expression(context, lexer);
-  token := transpiler_lex(lexer);
-  write_semicolon()
-end;
-
-proc transpile_variable_part(context: PTranspilerContext,  lexer: PLexer) -> BOOLEAN;
-var
-  token: LexerToken;
-  result: BOOLEAN;
-begin
-  token := lexer_current(lexer);
-  result := token.kind = lexerKindVar;
-
-  if result then
-    WriteString('VAR');
-    WriteLn();
-    token := transpiler_lex(lexer);
-
-    while token.kind = lexerKindIdentifier do
-      transpile_variable_declaration(context, lexer);
-      token := transpiler_lex(lexer)
-    end
+    result := transpile_named_type(context)
   end;
   return result
 end;
 
-proc transpile_procedure_heading(context: PTranspilerContext, lexer: PLexer) -> LexerToken;
+proc transpile_type_declaration(context: PTranspilerContext) -> PAstTypeDeclaration;
+var
+  token: LexerToken;
+  result: PAstTypeDeclaration;
+  written_bytes: CARDINAL;
+begin
+  WriteString(context^.output, '  ');
+  token := lexer_current(context^.lexer);
+
+  ALLOCATE(result, TSIZE(AstTypeDeclaration));
+  result^.identifier := token.identifierKind;
+
+  written_bytes := WriteNBytes(context^.output, ORD(token.identifierKind[1]), ADR(token.identifierKind[2]));
+
+  token := transpiler_lex(context^.lexer);
+  WriteString(context^.output, ' = ');
+  result^.type_expression := transpile_type_expression(context);
+  token := transpiler_lex(context^.lexer);
+  write_semicolon(context^.output);
+
+  return result
+end;
+
+proc transpile_type_part(context: PTranspilerContext) -> PPAstTypeDeclaration;
+var
+  token: LexerToken;
+  result: PPAstTypeDeclaration;
+  current_declaration: PPAstTypeDeclaration;
+  declaration_count: CARDINAL;
+begin
+  token := lexer_current(context^.lexer);
+
+  ALLOCATE(result, TSIZE(PAstTypeDeclaration));
+  current_declaration := result;
+  declaration_count := 0;
+
+  if token.kind = lexerKindType then
+    WriteString(context^.output, 'TYPE');
+    WriteLine(context^.output);
+    token := transpiler_lex(context^.lexer);
+
+    while token.kind = lexerKindIdentifier do
+      INC(declaration_count);
+
+      REALLOCATE(result, TSIZE(PAstTypeDeclaration) * (declaration_count + 1));
+      current_declaration := result;
+      INC(current_declaration, TSIZE(PAstTypeDeclaration) * (declaration_count - 1));
+
+      current_declaration^ := transpile_type_declaration(context);
+      token := transpiler_lex(context^.lexer)
+    end;
+    WriteLine(context^.output)
+  end;
+  if declaration_count <> 0 then
+    INC(current_declaration, TSIZE(PAstTypeDeclaration))
+  end;
+  current_declaration^ := nil;
+  return result
+end;
+
+proc transpile_variable_declaration(context: PTranspilerContext);
+var
+  token: LexerToken;
+  type_expression: PAstTypeExpression;
+begin
+  WriteString(context^.output, '  ');
+  token := lexer_current(context^.lexer);
+  write_current(context^.lexer, context^.output);
+
+  token := transpiler_lex(context^.lexer);
+  WriteString(context^.output, ': ');
+  type_expression := transpile_type_expression(context);
+  token := transpiler_lex(context^.lexer);
+  write_semicolon(context^.output)
+end;
+
+proc transpile_variable_part(context: PTranspilerContext) -> PPAstVariableDeclaration;
+var
+  token: LexerToken;
+begin
+  token := lexer_current(context^.lexer);
+
+  if token.kind = lexerKindVar then
+    WriteString(context^.output, 'VAR');
+    WriteLine(context^.output);
+    token := transpiler_lex(context^.lexer);
+
+    while token.kind = lexerKindIdentifier do
+      transpile_variable_declaration(context);
+      token := transpiler_lex(context^.lexer)
+    end
+  end;
+  return nil
+end;
+
+proc transpile_procedure_heading(context: PTranspilerContext) -> LexerToken;
 var
   token: LexerToken;
   result: LexerToken;
-  written_bytes: CARDINAL;
+  type_expression: PAstTypeExpression;
 begin
-  WriteString('PROCEDURE ');
+  WriteString(context^.output, 'PROCEDURE ');
 
-  result := transpiler_lex(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
+  result := transpiler_lex(context^.lexer);
+  write_current(context^.lexer, context^.output);
 
-  token := transpiler_lex(lexer);
-  Write('(');
+  token := transpiler_lex(context^.lexer);
+  WriteChar(context^.output, '(');
 
-  token := transpiler_lex(lexer);
+  token := transpiler_lex(context^.lexer);
   while token.kind <> lexerKindRightParen do
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
+    write_current(context^.lexer, context^.output);
 
-    token := transpiler_lex(lexer);
-    WriteString(': ');
+    token := transpiler_lex(context^.lexer);
+    WriteString(context^.output, ': ');
 
-    transpile_type_expression(context, lexer);
+    type_expression := transpile_type_expression(context);
 
-    token := transpiler_lex(lexer);
+    token := transpiler_lex(context^.lexer);
     if (token.kind = lexerKindSemicolon) or (token.kind = lexerKindComma) then
-      WriteString('; ');
-      token := transpiler_lex(lexer)
+      WriteString(context^.output, '; ');
+      token := transpiler_lex(context^.lexer)
     end
   end;
-  WriteString(')');
-  token := transpiler_lex(lexer);
+  WriteString(context^.output, ')');
+  token := transpiler_lex(context^.lexer);
 
   (* Check for the return type and write it. *)
   if token.kind = lexerKindArrow then
-    WriteString(': ');
-    token := transpiler_lex(lexer);
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-    token := transpiler_lex(lexer)
+    WriteString(context^.output, ': ');
+    token := transpiler_lex(context^.lexer);
+    write_current(context^.lexer, context^.output);
+    token := transpiler_lex(context^.lexer)
   end;
-  token := transpiler_lex(lexer);
-  write_semicolon();
+  token := transpiler_lex(context^.lexer);
+  write_semicolon(context^.output);
 
   return result
 end;
 
-proc transpile_expression(context: PTranspilerContext,  lexer: PLexer, trailing_token: LexerKind);
+proc transpile_expression(context: PTranspilerContext, trailing_token: LexerKind);
 var
   token: LexerToken;
   written_bytes: CARDINAL;
 begin
-  token := transpiler_lex(lexer);
+  token := transpiler_lex(context^.lexer);
 
   while (token.kind <> trailing_token) & (token.kind <> lexerKindEnd) do
     written_bytes := 0;
     if token.kind = lexerKindNull then
-      WriteString('NIL ');
+      WriteString(context^.output, 'NIL ');
+      written_bytes := 1
+    end;
+    if (token.kind = lexerKindBoolean) & token.booleanKind then
+      WriteString(context^.output, 'TRUE ');
+      written_bytes := 1
+    end;
+    if (token.kind = lexerKindBoolean) & (~token.booleanKind) then
+      WriteString(context^.output, 'FALSE ');
       written_bytes := 1
     end;
     if token.kind = lexerKindOr then
-      WriteString('OR ');
+      WriteString(context^.output, 'OR ');
       written_bytes := 1
     end;
     if token.kind = lexerKindAnd then
-      WriteString('AND ');
+      WriteString(context^.output, 'AND ');
       written_bytes := 1
     end;
     if token.kind = lexerKindNot then
-      WriteString('NOT ');
+      WriteString(context^.output, 'NOT ');
       written_bytes := 1
     end;
     if written_bytes = 0 then
-      written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-      Write(' ')
+      write_current(context^.lexer, context^.output);
+      WriteChar(context^.output, ' ')
     end;
-    token := transpiler_lex(lexer)
+    token := transpiler_lex(context^.lexer)
   end
 end;
 
-proc transpile_if_statement(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_if_statement(context: PTranspilerContext);
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
 begin
-  WriteString('  IF ');
-  transpile_expression(context, lexer, lexerKindThen);
+  WriteString(context^.output, '  IF ');
+  transpile_expression(context, lexerKindThen);
 
-  WriteString('THEN');
-  WriteLn();
-  transpile_statements(context, lexer);
-  WriteString('  END');
-  token := transpiler_lex(lexer)
+  WriteString(context^.output, 'THEN');
+  WriteLine(context^.output);
+  transpile_statements(context);
+  WriteString(context^.output, '  END');
+  token := transpiler_lex(context^.lexer)
 end;
 
-proc transpile_while_statement(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_while_statement(context: PTranspilerContext);
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
 begin
-  WriteString('  WHILE ');
-  transpile_expression(context, lexer, lexerKindDo);
+  WriteString(context^.output, '  WHILE ');
+  transpile_expression(context, lexerKindDo);
 
-  WriteString('DO');
-  WriteLn();
-  transpile_statements(context, lexer);
-  WriteString('  END');
-  token := transpiler_lex(lexer)
+  WriteString(context^.output, 'DO');
+  WriteLine(context^.output);
+  transpile_statements(context);
+  WriteString(context^.output, '  END');
+  token := transpiler_lex(context^.lexer)
 end;
 
-proc transpile_assignment_statement(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_assignment_statement(context: PTranspilerContext);
 begin
-  WriteString(' := ');
-  transpile_expression(context, lexer, lexerKindSemicolon);
+  WriteString(context^.output, ' := ');
+  transpile_expression(context, lexerKindSemicolon);
 end;
 
-proc transpile_call_statement(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_call_statement(context: PTranspilerContext);
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
 begin
-  WriteString('(');
-  token := transpiler_lex(lexer);
+  WriteString(context^.output, '(');
+  token := transpiler_lex(context^.lexer);
 
   while (token.kind <> lexerKindSemicolon) & (token.kind <> lexerKindEnd) do
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-    token := transpiler_lex(lexer)
+    write_current(context^.lexer, context^.output);
+    token := transpiler_lex(context^.lexer)
   end
 end;
 
-proc transpile_designator_expression(context: PTranspilerContext, lexer: PLexer);
+proc transpile_designator_expression(context: PTranspilerContext);
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
 begin
-  WriteString('  ');
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-  token := transpiler_lex(lexer);
+  WriteString(context^.output, '  ');
+  write_current(context^.lexer, context^.output);
+  token := transpiler_lex(context^.lexer);
 
   while token.kind = lexerKindLeftSquare do
-    Write('[');
-    token := transpiler_lex(lexer);
+    WriteChar(context^.output, '[');
+    token := transpiler_lex(context^.lexer);
     while token.kind <> lexerKindRightSquare do
-      written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-      token := transpiler_lex(lexer)
+      write_current(context^.lexer, context^.output);
+      token := transpiler_lex(context^.lexer)
     end;
-    Write(']');
-    token := transpiler_lex(lexer)
+    WriteChar(context^.output, ']');
+    token := transpiler_lex(context^.lexer)
   end;
   if token.kind = lexerKindHat then
-    Write('^');
-    token := transpiler_lex(lexer)
+    WriteChar(context^.output, '^');
+    token := transpiler_lex(context^.lexer)
   end;
   if token.kind = lexerKindDot then
-    Write('.');
-    token := transpiler_lex(lexer);
-    written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-    token := transpiler_lex(lexer)
+    WriteChar(context^.output, '.');
+    token := transpiler_lex(context^.lexer);
+    write_current(context^.lexer, context^.output);
+    token := transpiler_lex(context^.lexer)
   end;
   if token.kind = lexerKindHat then
-    Write('^');
-    token := transpiler_lex(lexer)
+    WriteChar(context^.output, '^');
+    token := transpiler_lex(context^.lexer)
   end;
   while token.kind = lexerKindLeftSquare do
-    Write('[');
-    token := transpiler_lex(lexer);
+    WriteChar(context^.output, '[');
+    token := transpiler_lex(context^.lexer);
     while token.kind <> lexerKindRightSquare do
-      written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-      token := transpiler_lex(lexer)
+      write_current(context^.lexer, context^.output);
+      token := transpiler_lex(context^.lexer)
     end;
-    Write(']');
-    token := transpiler_lex(lexer)
+    WriteChar(context^.output, ']');
+    token := transpiler_lex(context^.lexer)
   end
 end;
 
-proc transpile_return_statement(context: PTranspilerContext, lexer: PLexer);
+proc transpile_return_statement(context: PTranspilerContext);
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
 begin
-  WriteString('  RETURN ');
-  token := transpiler_lex(lexer);
-  written_bytes := WriteNBytes(StdOut, ADDRESS(lexer^.Current - lexer^.Start), lexer^.Start);
-  token := transpiler_lex(lexer)
+  WriteString(context^.output, '  RETURN ');
+  transpile_expression(context, lexerKindSemicolon)
 end;
 
-proc transpile_statement(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_statement(context: PTranspilerContext);
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
 begin
-  token := transpiler_lex(lexer);
+  token := transpiler_lex(context^.lexer);
 
   if token.kind = lexerKindIf then
-    transpile_if_statement(context, lexer)
+    transpile_if_statement(context)
   end;
   if token.kind = lexerKindWhile then
-    transpile_while_statement(context, lexer)
+    transpile_while_statement(context)
   end;
   if token.kind = lexerKindReturn then
-    transpile_return_statement(context, lexer)
+    transpile_return_statement(context)
   end;
   if token.kind = lexerKindIdentifier then
-    transpile_designator_expression(context, lexer);
-    token := lexer_current(lexer);
+    transpile_designator_expression(context);
+    token := lexer_current(context^.lexer);
 
     if token.kind = lexerKindAssignment then
-      transpile_assignment_statement(context, lexer)
+      transpile_assignment_statement(context)
     end;
     if token.kind = lexerKindLeftParen then
-      transpile_call_statement(context, lexer)
+      transpile_call_statement(context)
     end
   end
 end;
 
-proc transpile_statements(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_statements(context: PTranspilerContext);
 var
   token: LexerToken;
 begin
-  token := lexer_current(lexer);
+  token := lexer_current(context^.lexer);
 
   while token.kind <> lexerKindEnd do
-    transpile_statement(context, lexer);
-    token := lexer_current(lexer);
+    transpile_statement(context);
+    token := lexer_current(context^.lexer);
 
     if token.kind = lexerKindSemicolon then
-      Write(';')
+      WriteChar(context^.output, ';')
     end;
-    WriteLn()
+    WriteLine(context^.output)
   end
 end;
 
-proc transpile_statement_part(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_statement_part(context: PTranspilerContext);
 var
   token: LexerToken;
 begin
-  token := lexer_current(lexer);
+  token := lexer_current(context^.lexer);
   if token.kind = lexerKindBegin then
-    WriteString('BEGIN');
-    WriteLn();
-    transpile_statements(context, lexer)
+    WriteString(context^.output, 'BEGIN');
+    WriteLine(context^.output);
+    transpile_statements(context)
   end
 end;
 
-proc transpile_procedure_declaration(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_procedure_declaration(context: PTranspilerContext);
 var
   token: LexerToken;
-  seen_part: BOOLEAN;
+  seen_variables: PPAstVariableDeclaration;
   written_bytes: CARDINAL;
+  seen_constants: PPAstConstantDeclaration;
 begin
-  token := transpile_procedure_heading(context, lexer);
-  seen_part := transpile_constant_part(context, lexer);
-  seen_part := transpile_variable_part(context, lexer);
-  transpile_statement_part(context, lexer);
+  token := transpile_procedure_heading(context);
+  seen_constants := transpile_constant_part(context);
+  seen_variables := transpile_variable_part(context);
+  transpile_statement_part(context);
 
-  WriteString('END ');
-  written_bytes := WriteNBytes(StdOut, ORD(token.identifierKind[1]), ADR(token.identifierKind[2]));
+  WriteString(context^.output, 'END ');
+  written_bytes := WriteNBytes(context^.output, ORD(token.identifierKind[1]), ADR(token.identifierKind[2]));
 
-  token := transpiler_lex(lexer);
-  write_semicolon();
-  token := transpiler_lex(lexer)
+  token := transpiler_lex(context^.lexer);
+  write_semicolon(context^.output);
+  token := transpiler_lex(context^.lexer)
 end;
 
-proc transpile_procedure_part(context: PTranspilerContext,  lexer: PLexer);
+proc transpile_procedure_part(context: PTranspilerContext);
 var
   token: LexerToken;
 begin
-  token := lexer_current(lexer);
+  token := lexer_current(context^.lexer);
 
   while token.kind = lexerKindProc do
-    transpile_procedure_declaration(context, lexer);
-    token := lexer_current(lexer);
-    WriteLn()
+    transpile_procedure_declaration(context);
+    token := lexer_current(context^.lexer);
+    WriteLine(context^.output)
   end
 end;
 
-proc transpile(lexer: PLexer);
+proc transpile(lexer: PLexer, output: File);
 var
   token: LexerToken;
-  written_bytes: CARDINAL;
   context: TranspilerContext;
+  ast_module: PAstModule;
 begin
-  transpile_module(ADR(context), lexer)
+  context.indentation := 0;
+  context.output := output;
+  context.lexer := lexer;
+
+  ast_module := transpile_module(ADR(context))
 end;
 
 end Transpiler.