🐐 Negation

tests.py

@@ -8,7 +8,7 @@ from centvrion.ast_nodes import (
   Bool, BinOp, BuiltIn, DataArray, DataRangeArray, Defini,
   Designa, DumStatement, Erumpe, ExpressionStatement, ID,
   Invoca, ModuleCall, Nullus, Numeral, PerStatement,
-  Program, Redi, SiStatement, String,
+  Program, Redi, SiStatement, String, UnaryMinus,
   num_to_int, int_to_num, make_string,
 )
 from centvrion.lexer import Lexer
@@ -105,6 +105,10 @@ arithmetic_tests = [
   ("X / III", None, ValInt(3)),           # integer division: 10 // 3 = 3
   ("II + III * IV", None, ValInt(14)),    # precedence: 2 + (3*4) = 14
   ("(II + III) * IV", None, ValInt(20)),  # parens: (2+3)*4 = 20
+  ("- III", None, ValInt(-3)),            # unary negation
+  ("- (II + III)", None, ValInt(-5)),     # unary negation of expression
+  ("- - II", None, ValInt(2)),            # double negation
+  ("III + - II", None, ValInt(1)),        # unary in binary context
 ]
 
 class TestArithmetic(unittest.TestCase):