🐐 NVLLVUS fix

centvrion/ast_nodes.py

@@ -133,8 +133,11 @@ def int_to_num(n, m, s=False) -> str:
       for i in thousands_chars
     ])
 
-    return thousands + int_to_num(n % 1000, m, s)
+    remainder = n % 1000
+    return thousands + (int_to_num(remainder, m, s) if remainder else "")
   else:
+    if n == 0:
+      return "NVLLVS"
     nums = []
     while n > 0:
       for num, i in list(NUMERALS.items())[::-1]:
@@ -779,8 +782,14 @@ class BinOp(Node):
           raise CentvrionError("Cannot compare strings or arrays with PLVS")
         return vtable, ValBool((lv or 0) > (rv or 0))
       case "KEYWORD_EST":
+        if ((isinstance(left, ValInt) and lv == 0 and isinstance(right, ValNul)) or
+            (isinstance(left, ValNul) and isinstance(right, ValInt) and rv == 0)):
+          return vtable, ValBool(True)
         return vtable, ValBool(lv == rv)
       case "KEYWORD_DISPAR":
+        if ((isinstance(left, ValInt) and lv == 0 and isinstance(right, ValNul)) or
+            (isinstance(left, ValNul) and isinstance(right, ValInt) and rv == 0)):
+          return vtable, ValBool(False)
         return vtable, ValBool(lv != rv)
       case "KEYWORD_ET":
         return vtable, ValBool(bool(left) and bool(right))

centvrion/compiler/runtime/cent_runtime.c

@@ -177,8 +177,12 @@ static void transform_thousands(const char *src, char *dst, size_t dstsz) {
 }
 
 void cent_int_to_roman(long n, char *buf, size_t bufsz) {
-  if (n <= 0 || (n > 3999 && !cent_magnvm))
+  if (n == 0) {
-    cent_runtime_error("number out of range for Roman numerals (1-3999)");
+    if (bufsz > 6) { memcpy(buf, "NVLLVS", 6); buf[6] = '\0'; }
+    return;
+  }
+  if (n < 0 || (n > 3999 && !cent_magnvm))
+    cent_runtime_error("number out of range for Roman numerals");
   size_t pos = 0;
   if (n > 3999) {
     char base[64];
@@ -480,6 +484,9 @@ CentValue cent_mod_frac(CentValue a, CentValue b) {
 }
 
 CentValue cent_eq(CentValue a, CentValue b) {
+  if ((a.type == CENT_INT && a.ival == 0 && b.type == CENT_NULL) ||
+      (a.type == CENT_NULL && b.type == CENT_INT && b.ival == 0))
+    return cent_bool(1);
   if ((a.type == CENT_INT || a.type == CENT_FRAC) &&
       (b.type == CENT_INT || b.type == CENT_FRAC)) {
     long an, ad, bn, bd;

tests.py

@@ -881,7 +881,7 @@ class TestNumerals(unittest.TestCase):
 
   # int_to_num: valid cases
   def test_int_to_num(self):
-    for n, s in [(1,"I"),(4,"IV"),(9,"IX"),(40,"XL"),(42,"XLII"),(3999,"MMMCMXCIX")]:
+    for n, s in [(0,"NVLLVS"),(1,"I"),(4,"IV"),(9,"IX"),(40,"XL"),(42,"XLII"),(3999,"MMMCMXCIX")]:
       self.assertEqual(int_to_num(n, False), s)
 
   def test_int_to_num_above_3999_raises(self):
@@ -907,6 +907,9 @@ class TestMakeString(unittest.TestCase):
   def test_int(self):
     self.assertEqual(make_string(ValInt(3)), "III")
 
+  def test_int_zero(self):
+    self.assertEqual(make_string(ValInt(0)), "NVLLVS")
+
   def test_bool_true(self):
     self.assertEqual(make_string(ValBool(True)), "VERITAS")
 
@@ -939,6 +942,8 @@ dic_type_tests = [
   ('DIC("")', Program([], [ExpressionStatement(BuiltIn("DIC", [String("")]))]), ValStr(""), "\n"),
   # arithmetic result printed as numeral
   ("DIC(II + III)", Program([], [ExpressionStatement(BuiltIn("DIC", [BinOp(Numeral("II"), Numeral("III"), "SYMBOL_PLUS")]))]), ValStr("V"), "V\n"),
+  # integer 0 prints as NVLLVS
+  ("DIC(I - I)", Program([], [ExpressionStatement(BuiltIn("DIC", [BinOp(Numeral("I"), Numeral("I"), "SYMBOL_MINUS")]))]), ValStr("NVLLVS"), "NVLLVS\n"),
   # multiple args of mixed types
   ('DIC("x", VERITAS)', Program([], [ExpressionStatement(BuiltIn("DIC", [String("x"), Bool(True)]))]), ValStr("x VERITAS"), "x VERITAS\n"),
 ]
@@ -1062,6 +1067,8 @@ interpolation_tests = [
     Program([], [
       ExpressionStatement(InterpolatedString([String("value: "), Nullus()]))
     ]), ValStr("value: NVLLVS")),
+  # integer 0 interpolates as NVLLVS
+  ('"value: {I - I}"', Program([], [ExpressionStatement(InterpolatedString([String("value: "), BinOp(Numeral("I"), Numeral("I"), "SYMBOL_MINUS")]))]), ValStr("value: NVLLVS")),
   # expression-only string (no literal parts around it)
   ('DESIGNA x VT "hi"\n"{x}"',
     Program([], [
@@ -1194,6 +1201,14 @@ comparison_tests = [
   ("NVLLVS DISPAR NVLLVS", Program([], [ExpressionStatement(BinOp(Nullus(), Nullus(), "KEYWORD_DISPAR"))]), ValBool(False)),
   # cross-type: an int and a string are never equal
   ('I DISPAR "I"', Program([], [ExpressionStatement(BinOp(Numeral("I"), String("I"), "KEYWORD_DISPAR"))]), ValBool(True)),
+  # integer 0 equals NVLLVS
+  ("(I - I) EST NVLLVS", Program([], [ExpressionStatement(BinOp(BinOp(Numeral("I"), Numeral("I"), "SYMBOL_MINUS"), Nullus(), "KEYWORD_EST"))]), ValBool(True)),
+  ("NVLLVS EST (I - I)", Program([], [ExpressionStatement(BinOp(Nullus(), BinOp(Numeral("I"), Numeral("I"), "SYMBOL_MINUS"), "KEYWORD_EST"))]), ValBool(True)),
+  ("(I - I) DISPAR NVLLVS", Program([], [ExpressionStatement(BinOp(BinOp(Numeral("I"), Numeral("I"), "SYMBOL_MINUS"), Nullus(), "KEYWORD_DISPAR"))]), ValBool(False)),
+  ("NVLLVS DISPAR (I - I)", Program([], [ExpressionStatement(BinOp(Nullus(), BinOp(Numeral("I"), Numeral("I"), "SYMBOL_MINUS"), "KEYWORD_DISPAR"))]), ValBool(False)),
+  # non-zero integer does not equal NVLLVS
+  ("I EST NVLLVS", Program([], [ExpressionStatement(BinOp(Numeral("I"), Nullus(), "KEYWORD_EST"))]), ValBool(False)),
+  ("NVLLVS DISPAR I", Program([], [ExpressionStatement(BinOp(Nullus(), Numeral("I"), "KEYWORD_DISPAR"))]), ValBool(True)),
 ]
 
 class TestComparisons(unittest.TestCase):