Parse and transpile unary operations

source/Parser.def

@@ -1,9 +1,55 @@
 DEFINITION MODULE Parser;
 
-FROM Common IMPORT Identifier, PIdentifier;
+FROM Common IMPORT Identifier, PIdentifier, ShortString;
 FROM Lexer IMPORT PLexer;
 
 TYPE
+  AstLiteralKind = (
+    astLiteralKindInteger,
+    astLiteralKindString,
+    astLiteralKindNull
+  );
+  AstLiteral = RECORD
+    CASE kind: AstLiteralKind OF
+      astLiteralKindInteger: integer: INTEGER |
+      astLiteralKindString: string: ShortString |
+      astLiteralKindNull:
+    END
+  END;
+  PAstLiteral = POINTER TO AstLiteral;
+
+  AstUnaryOperator = (
+    astUnaryOperatorNot,
+    astUnaryOperatorMinus
+  );
+
+  AstExpressionKind = (
+    astExpressionKindLiteral,
+    astExpressionKindIdentifier,
+    astExpressionKindArrayAccess,
+    astExpressionKindDereference,
+    astExpressionKindFieldAccess,
+    astExpressionKindUnary
+  );
+  AstExpression = RECORD 
+    CASE kind: AstExpressionKind OF
+      astExpressionKindLiteral: literal: PAstLiteral |
+      astExpressionKindIdentifier: identifier: Identifier |
+      astExpressionKindDereference: reference: PAstExpression |
+      astExpressionKindArrayAccess:
+        array: PAstExpression;
+        index: PAstExpression |
+      astExpressionKindFieldAccess:
+        aggregate: PAstExpression;
+        field: Identifier |
+      astExpressionKindUnary:
+        unary_operator: AstUnaryOperator;
+        unary_operand: PAstExpression
+    END
+  END;
+  PAstExpression = POINTER TO AstExpression;
+  PPAstExpression = POINTER TO PAstExpression;
+
   AstImportStatement = RECORD
     package: Identifier;
     symbols: PIdentifier
@@ -74,5 +120,6 @@ PROCEDURE parse_type_part(lexer: PLexer): PPAstTypeDeclaration;
 PROCEDURE parse_variable_part(lexer: PLexer): PPAstVariableDeclaration;
 PROCEDURE parse_constant_part(lexer: PLexer): PPAstConstantDeclaration;
 PROCEDURE parse_import_part(lexer: PLexer): PPAstImportStatement;
+PROCEDURE parse_designator(lexer: PLexer): PAstExpression;
 
 END Parser.