🐐 SENATVS

README.md

@@ -22,6 +22,33 @@ Variables are set with the `DESIGNA` and `VT` keywords. Type is inferred.
 
 Variable can consist of lower-case letters, numbers, as well as `_`.
 
+### Compound assignment
+
+`AVGE` (+=) and `MINVE` (-=) are shorthand for incrementing or decrementing a variable:
+
+![Compound assignment](snippets/compound.png)
+
+```
+> VIII
+```
+
+`x AVGE III` is equivalent to `DESIGNA x VT x + III`.
+
+### Destructuring
+
+Multiple variables can be assigned at once by unpacking an array or multi-return function:
+
+```
+DEFINI pair (a, b) VT { REDI (a, b) }
+DESIGNA x, y VT INVOCA pair (III, VII)
+```
+
+The number of targets must match the length of the array. This also works with array literals:
+
+```
+DESIGNA a, b, c VT [I, II, III]
+```
+
 ## Data types
 ### NVLLVS
 `NVLLVS` is a special kind of data type in `CENTVRION`, similar to the `null` value in many other languages. `NVLLVS` can be 0 if evaluated as an int or float, or an empty string if evaluated as a string. `NVLLVS` cannot be evaluated as a boolean.
@@ -209,6 +236,11 @@ Breaks out of the current loop (`DVM` or `PER`). Has no meaningful return value.
 
 Returns the length of `array` (element count) or `string` (character count) as an integer.
 
+### SENATVS
+`SENATVS(bool, ...)` or `SENATVS([bool])`
+
+Returns VERITAS if a strict majority of the arguments are VERITAS, FALSITAS otherwise. Also accepts a single array of booleans. All values must be booleans. Ties return FALSITAS.
+
 ## Modules
 Modules are additions to the base `CENTVRION` syntax. They add or change certain features. Modules are included in your code by having
 
@@ -221,12 +253,16 @@ Vnlike many other programming languages with modules, the modules in `CENTVRION`
 ### FORS
 ![CVM FORS](snippets/fors.png)
 
-The `FORS` module allows you to add randomness to your `CENTVRION` program. It adds 2 new built-in functions: `FORTIS_NVMERVS int int` and `FORTIS_ELECTIONIS ['a]`.
+The `FORS` module allows you to add randomness to your `CENTVRION` program. It adds 4 new built-in functions: `FORTIS_NVMERVS int int`, `FORTIS_ELECTIONIS ['a]`, `DECIMATIO ['a]`, and `SEMEN int`.
 
 `FORTIS_NVMERVS int int` picks a random int in the (inclusive) range of the two given ints.
 
 `FORTIS_ELECTIONIS ['a]` picks a random element from the given array. `FORTIS_ELECTIONIS array` is identical to ```array[FORTIS_NVMERVS NVLLVS ((LONGITVDO array)-I)]```.
 
+`DECIMATIO ['a]` returns a copy of the given array with a random tenth of its elements removed. Arrays with fewer than 10 elements are returned unchanged.
+
+`SEMEN int` seeds the random number generator for reproducibility.
+
 ### FRACTIO
 ![CVM FRACTIO](snippets/fractio.png)
 

centvrion/ast_nodes.py

@@ -431,6 +431,35 @@ class DesignaIndex(Node):
     return vtable, ValNul()
 
 
+class DesignaDestructure(Node):
+  def __init__(self, variables: list, value: Node) -> None:
+    self.ids = variables
+    self.value = value
+
+  def __eq__(self, other):
+    return type(self) == type(other) and self.ids == other.ids and self.value == other.value
+
+  def __repr__(self) -> str:
+    ids_string = ", ".join(repr(i) for i in self.ids)
+    value_string = repr(self.value).replace('\n', '\n  ')
+    return f"DesignaDestructure(\n  [{ids_string}],\n  {value_string}\n)"
+
+  def print(self):
+    ids_str = ", ".join(i.print() for i in self.ids)
+    return f"DESIGNA {ids_str} VT {self.value.print()}"
+
+  def _eval(self, vtable):
+    vtable, val = self.value.eval(vtable)
+    if not isinstance(val, ValList):
+      raise CentvrionError("Cannot destructure non-array value")
+    if len(val.value()) != len(self.ids):
+      raise CentvrionError(
+        f"Destructuring mismatch: {len(self.ids)} targets, {len(val.value())} values")
+    for id_node, item in zip(self.ids, val.value()):
+      vtable[id_node.name] = item
+    return vtable, ValNul()
+
+
 class Defini(Node):
   def __init__(self, name: ID, parameters: list[ID], statements: list[Node]) -> None:
     self.name = name
@@ -920,6 +949,34 @@ class BuiltIn(Node):
         if len(lst) == 0:
           raise CentvrionError("FORTIS_ELECTIONIS: cannot select from an empty array")
         return vtable, lst[random.randint(0, len(lst) - 1)]
+      case "SEMEN":
+        if "FORS" not in vtable["#modules"]:
+          raise CentvrionError("Cannot use 'SEMEN' without module 'FORS'")
+        seed = params[0].value()
+        if not isinstance(seed, int):
+          raise CentvrionError("SEMEN requires an integer seed")
+        random.seed(seed)
+        return vtable, ValNul()
+      case "DECIMATIO":
+        if "FORS" not in vtable["#modules"]:
+          raise CentvrionError("Cannot use 'DECIMATIO' without module 'FORS'")
+        if not isinstance(params[0], ValList):
+          raise CentvrionError("DECIMATIO requires an array")
+        arr = list(params[0].value())
+        to_remove = len(arr) // 10
+        for _ in range(to_remove):
+          arr.pop(random.randint(0, len(arr) - 1))
+        return vtable, ValList(arr)
+      case "SENATVS":
+        if len(params) == 1 and isinstance(params[0], ValList):
+          items = params[0].value()
+        else:
+          items = params
+        for p in items:
+          if not isinstance(p, ValBool):
+            raise CentvrionError("SENATVS requires boolean arguments")
+        true_count = sum(1 for p in items if p.value())
+        return vtable, ValBool(true_count > len(items) / 2)
       case "LONGITVDO":
         if isinstance(params[0], (ValList, ValStr)):
           return vtable, ValInt(len(params[0].value()))

centvrion/compiler/emit_expr.py

@@ -186,6 +186,29 @@ def _emit_builtin(node, ctx):
       else:
         lines.append(f"CentValue {tmp} = cent_fortis_electionis({param_vars[0]});")
 
+    case "DECIMATIO":
+      if not ctx.has_module("FORS"):
+        lines.append('cent_runtime_error("FORS module required for DECIMATIO");')
+        lines.append(f"CentValue {tmp} = cent_null();")
+      else:
+        lines.append(f"CentValue {tmp} = cent_decimatio({param_vars[0]});")
+
+    case "SEMEN":
+      if not ctx.has_module("FORS"):
+        lines.append('cent_runtime_error("FORS module required for SEMEN");')
+        lines.append(f"CentValue {tmp} = cent_null();")
+      else:
+        lines.append(f"cent_semen({param_vars[0]});")
+        lines.append(f"CentValue {tmp} = cent_null();")
+
+    case "SENATVS":
+      if param_vars:
+        arr_tmp = ctx.fresh_tmp() + "_arr"
+        lines.append(f"CentValue {arr_tmp}[] = {{{', '.join(param_vars)}}};")
+        lines.append(f"CentValue {tmp} = cent_senatus({arr_tmp}, {len(param_vars)});")
+      else:
+        lines.append(f"CentValue {tmp} = cent_senatus(NULL, 0);")
+
     case "ERVMPE":
       # break as expression (side-effecting; result is unused)
       lines.append("break;")

centvrion/compiler/emit_stmt.py

@@ -1,6 +1,6 @@
 from centvrion.ast_nodes import (
-  Designa, DesignaIndex, SiStatement, DumStatement, PerStatement,
-  Defini, Redi, Erumpe, Continva, ExpressionStatement, ID,
+  Designa, DesignaIndex, DesignaDestructure, SiStatement, DumStatement,
+  PerStatement, Defini, Redi, Erumpe, Continva, ExpressionStatement, ID,
 )
 from centvrion.compiler.emit_expr import emit_expr
 
@@ -29,6 +29,18 @@ def emit_stmt(node, ctx):
       ]
     )
 
+  if isinstance(node, DesignaDestructure):
+    n = len(node.ids)
+    val_lines, val_var = emit_expr(node.value, ctx)
+    lines = val_lines[:]
+    lines.append(f'if ({val_var}.type != CENT_LIST) cent_type_error("Cannot destructure non-array value");')
+    lines.append(f'if ({val_var}.lval.len != {n}) cent_runtime_error("Destructuring mismatch");')
+    for i, id_node in enumerate(node.ids):
+      tmp = ctx.fresh_tmp()
+      lines.append(f"CentValue {tmp} = cent_list_index({val_var}, cent_int({i + 1}));")
+      lines.append(f'cent_scope_set(&_scope, "{id_node.name}", {tmp});')
+    return lines
+
   if isinstance(node, SiStatement):
     cond_lines, cond_var = emit_expr(node.test, ctx)
     then_lines = _emit_body(node.statements, ctx)

centvrion/compiler/runtime/cent_runtime.c

@@ -533,6 +533,46 @@ CentValue cent_fortis_electionis(CentValue lst) {
   return lst.lval.items[rand() % lst.lval.len];
 }
 
+CentValue cent_senatus(CentValue *args, int n) {
+  /* Single array argument: unpack it */
+  if (n == 1 && args[0].type == CENT_LIST) {
+    n = args[0].lval.len;
+    args = args[0].lval.items;
+  }
+  int true_count = 0;
+  for (int i = 0; i < n; i++) {
+    if (args[i].type != CENT_BOOL)
+      cent_type_error("'SENATVS' requires boolean arguments");
+    if (args[i].bval) true_count++;
+  }
+  return cent_bool(true_count * 2 > n);
+}
+
+CentValue cent_decimatio(CentValue lst) {
+  if (lst.type != CENT_LIST)
+    cent_type_error("'DECIMATIO' requires a list");
+  int len = lst.lval.len;
+  /* Copy the list so we can remove in-place */
+  CentValue result = cent_list_new(len);
+  for (int i = 0; i < len; i++)
+    cent_list_push(&result, lst.lval.items[i]);
+  int to_remove = result.lval.len / 10;
+  for (int i = 0; i < to_remove; i++) {
+    int idx = rand() % result.lval.len;
+    /* Shift remaining elements left */
+    for (int j = idx; j < result.lval.len - 1; j++)
+      result.lval.items[j] = result.lval.items[j + 1];
+    result.lval.len--;
+  }
+  return result;
+}
+
+void cent_semen(CentValue seed) {
+  if (seed.type != CENT_INT)
+    cent_type_error("'SEMEN' requires an integer seed");
+  srand((unsigned)seed.ival);
+}
+
 /* ------------------------------------------------------------------ */
 /* Array helpers                                                        */
 /* ------------------------------------------------------------------ */

centvrion/compiler/runtime/cent_runtime.h

@@ -177,7 +177,10 @@ CentValue cent_avdi_numerus(void);                    /* AVDI_NVMERVS */
 CentValue cent_longitudo(CentValue v);                  /* LONGITVDO  */
 CentValue cent_fortis_numerus(CentValue lo, CentValue hi); /* FORTIS_NVMERVS */
 CentValue cent_fortis_electionis(CentValue lst);          /* FORTIS_ELECTIONIS */
+CentValue cent_decimatio(CentValue lst);                       /* DECIMATIO */
+void      cent_semen(CentValue seed);                          /* SEMEN */
 void      cent_everro(void);                                   /* EVERRO */
+CentValue cent_senatus(CentValue *args, int n);                /* SENATVS */
 
 /* ------------------------------------------------------------------ */
 /* Array helpers                                                        */

centvrion/lexer.py

@@ -5,6 +5,7 @@ valid_characters = '|'.join(list("abcdefghiklmnopqrstvxyz_"))
 keyword_tokens = [("KEYWORD_"+i, i) for i in [
   "AETERNVM",
   "ALVID",
+  "AVGE",
   "AVT",
   "DEFINI",
   "DESIGNA",
@@ -19,6 +20,7 @@ keyword_tokens = [("KEYWORD_"+i, i) for i in [
   "FALSITAS",
   "INVOCA",
   "IN",
+  "MINVE",
   "MINVS",
   "NON",
   "NVLLVS",
@@ -37,11 +39,14 @@ keyword_tokens = [("KEYWORD_"+i, i) for i in [
 builtin_tokens = [("BUILTIN", i) for i in [
   "AVDI_NVMERVS",
   "AVDI",
+  "DECIMATIO",
   "DICE",
   "EVERRO",
   "FORTIS_NVMERVS",
   "FORTIS_ELECTIONIS",
-  "LONGITVDO"
+  "LONGITVDO",
+  "SEMEN",
+  "SENATVS"
 ]]
 
 data_tokens = [

centvrion/parser.py

@@ -74,6 +74,18 @@ class Parser():
     def statement_designa_index(tokens):
       return ast_nodes.DesignaIndex(tokens[1], tokens[3], tokens[6])
 
+    @self.pg.production('statement : KEYWORD_DESIGNA id SYMBOL_COMMA id_list_rest KEYWORD_VT expression')
+    def statement_designa_destructure(tokens):
+      return ast_nodes.DesignaDestructure([tokens[1]] + tokens[3], tokens[5])
+
+    @self.pg.production('statement : id KEYWORD_AVGE expression')
+    def statement_avge(tokens):
+      return ast_nodes.Designa(tokens[0], ast_nodes.BinOp(tokens[0], tokens[2], "SYMBOL_PLUS"))
+
+    @self.pg.production('statement : id KEYWORD_MINVE expression')
+    def statement_minve(tokens):
+      return ast_nodes.Designa(tokens[0], ast_nodes.BinOp(tokens[0], tokens[2], "SYMBOL_MINUS"))
+
     @self.pg.production('statement : expression')
     def statement_expression(tokens):
       return ast_nodes.ExpressionStatement(tokens[0])
@@ -250,6 +262,14 @@ class Parser():
       else:
         return [calls[0]] + calls[2]
 
+    @self.pg.production('id_list_rest : id')
+    @self.pg.production('id_list_rest : id SYMBOL_COMMA id_list_rest')
+    def id_list_rest(calls):
+      if len(calls) == 1:
+        return [calls[0]]
+      else:
+        return [calls[0]] + calls[2]
+
     @self.pg.production("id : ID")
     def id_expression(tokens):
       return ast_nodes.ID(tokens[0].value)

language/main.tex

@@ -30,6 +30,9 @@
       \multicolumn{3}{|c|}{\textbf{Statements}} \\ \hline
         \languageline{statement}{\textit{expression}} \\
         \languageline{statement}{\texttt{DESIGNA} \textbf{id} \texttt{VT} \textit{expression}} \\
+        \languageline{statement}{\texttt{DESIGNA} \textbf{id} \texttt{,} \textit{ids} \texttt{VT} \textit{expression}} \\
+        \languageline{statement}{\textbf{id} \texttt{AVGE} \textit{expression}} \\
+        \languageline{statement}{\textbf{id} \texttt{MINVE} \textit{expression}} \\
         \languageline{statement}{\texttt{DEFINI} \textbf{id} \texttt{(} \textit{optional-ids} \texttt{)} \texttt{VT} \textit{scope}} \\
         \languageline{statement}{\textit{if-statement}} \\
         \languageline{statement}{\texttt{DVM} \textit{expression} \texttt{FACE} \textit{scope}} \\

snippets/compound.cent

@@ -0,0 +1,3 @@
+DESIGNA x VT V
+x AVGE III
+DICE(x)

snippets/syntaxes/centvrion.sublime-syntax

@@ -57,7 +57,7 @@ contexts:
       scope: constant.language.centvrion
 
   builtins:
-    - match: '\b(AVDI_NVMERVS|AVDI|DICE|FORTIS_NVMERVS|FORTIS_ELECTIONIS|LONGITVDO)\b'
+    - match: '\b(AVDI_NVMERVS|AVDI|DECIMATIO|DICE|FORTIS_NVMERVS|FORTIS_ELECTIONIS|LONGITVDO|SEMEN)\b'
       scope: support.function.builtin.centvrion
 
   modules:
@@ -65,7 +65,7 @@ contexts:
       scope: support.class.module.centvrion
 
   keywords:
-    - match: '\b(AETERNVM|ALVID|AVT|DEFINI|DESIGNA|DONICVM|DVM|ERVMPE|EST|ET|FACE|INVOCA|IN|MINVS|NON|PER|PLVS|REDI|RELIQVVM|SI|TVNC|VSQVE|VT|CVM)\b'
+    - match: '\b(AETERNVM|ALVID|AVGE|AVT|CONTINVA|DEFINI|DESIGNA|DONICVM|DVM|ERVMPE|EST|ET|FACE|INVOCA|IN|MINVE|MINVS|NON|PER|PLVS|REDI|RELIQVVM|SI|TVNC|VSQVE|VT|CVM)\b'
       scope: keyword.control.centvrion
 
   operators:

tests.py

@@ -11,8 +11,8 @@ from fractions import Fraction
 
 from centvrion.ast_nodes import (
   ArrayIndex, Bool, BinOp, BuiltIn, DataArray, DataRangeArray, Defini,
-  Continva, Designa, DesignaIndex, DumStatement, Erumpe, ExpressionStatement, ID,
-  Invoca, ModuleCall, Nullus, Numeral, PerStatement,
+  Continva, Designa, DesignaDestructure, DesignaIndex, DumStatement, Erumpe,
+  ExpressionStatement, ID, Invoca, ModuleCall, Nullus, Numeral, PerStatement,
   Program, Redi, SiStatement, String, UnaryMinus, UnaryNot,
   Fractio, frac_to_fraction, fraction_to_frac,
   num_to_int, int_to_num, make_string,
@@ -265,6 +265,31 @@ assignment_tests = [
                  Designa(ID("x"), BinOp(ID("x"), Numeral("I"), "SYMBOL_PLUS")),
                  ExpressionStatement(ID("x"))]),
     ValInt(3)),
+  # Compound assignment — AVGE (+=)
+  ("DESIGNA x VT V\nx AVGE III\nx",
+    Program([], [Designa(ID("x"), Numeral("V")),
+                 Designa(ID("x"), BinOp(ID("x"), Numeral("III"), "SYMBOL_PLUS")),
+                 ExpressionStatement(ID("x"))]),
+    ValInt(8)),
+  # Compound assignment — MINVE (-=)
+  ("DESIGNA x VT X\nx MINVE III\nx",
+    Program([], [Designa(ID("x"), Numeral("X")),
+                 Designa(ID("x"), BinOp(ID("x"), Numeral("III"), "SYMBOL_MINUS")),
+                 ExpressionStatement(ID("x"))]),
+    ValInt(7)),
+  # AVGE with complex expression
+  ("DESIGNA x VT I\nx AVGE II + III\nx",
+    Program([], [Designa(ID("x"), Numeral("I")),
+                 Designa(ID("x"), BinOp(ID("x"), BinOp(Numeral("II"), Numeral("III"), "SYMBOL_PLUS"), "SYMBOL_PLUS")),
+                 ExpressionStatement(ID("x"))]),
+    ValInt(6)),
+  # AVGE inside a loop (DONICVM range is exclusive of upper bound: I VSQVE III = [1, 2])
+  ("DESIGNA s VT NVLLVS\nDONICVM i VT I VSQVE III FACE {\ns AVGE i\n}\ns",
+    Program([], [Designa(ID("s"), Nullus()),
+                 PerStatement(DataRangeArray(Numeral("I"), Numeral("III")), ID("i"),
+                   [Designa(ID("s"), BinOp(ID("s"), ID("i"), "SYMBOL_PLUS"))]),
+                 ExpressionStatement(ID("s"))]),
+    ValInt(3)),
 ]
 
 class TestAssignment(unittest.TestCase):
@@ -273,6 +298,57 @@ class TestAssignment(unittest.TestCase):
     run_test(self, source, nodes, value)
 
 
+# --- Destructuring ---
+
+destructuring_tests = [
+  # basic: unpack multi-return function
+  (
+    "DEFINI pair (a, b) VT { REDI (a, b) }\nDESIGNA x, y VT INVOCA pair (III, VII)\nx + y",
+    Program([], [
+      Defini(ID("pair"), [ID("a"), ID("b")], [Redi([ID("a"), ID("b")])]),
+      DesignaDestructure([ID("x"), ID("y")], Invoca(ID("pair"), [Numeral("III"), Numeral("VII")])),
+      ExpressionStatement(BinOp(ID("x"), ID("y"), "SYMBOL_PLUS")),
+    ]),
+    ValInt(10),
+  ),
+  # unpack array literal
+  (
+    "DESIGNA a, b VT [I, II]\na + b",
+    Program([], [
+      DesignaDestructure([ID("a"), ID("b")], DataArray([Numeral("I"), Numeral("II")])),
+      ExpressionStatement(BinOp(ID("a"), ID("b"), "SYMBOL_PLUS")),
+    ]),
+    ValInt(3),
+  ),
+  # three variables
+  (
+    "DESIGNA a, b, c VT [X, XX, XXX]\na + b + c",
+    Program([], [
+      DesignaDestructure([ID("a"), ID("b"), ID("c")], DataArray([Numeral("X"), Numeral("XX"), Numeral("XXX")])),
+      ExpressionStatement(BinOp(BinOp(ID("a"), ID("b"), "SYMBOL_PLUS"), ID("c"), "SYMBOL_PLUS")),
+    ]),
+    ValInt(60),
+  ),
+  # destructure into individual use
+  (
+    "DEFINI pair (a, b) VT { REDI (a, b) }\nDESIGNA x, y VT INVOCA pair (V, II)\nDICE(x)\nDICE(y)",
+    Program([], [
+      Defini(ID("pair"), [ID("a"), ID("b")], [Redi([ID("a"), ID("b")])]),
+      DesignaDestructure([ID("x"), ID("y")], Invoca(ID("pair"), [Numeral("V"), Numeral("II")])),
+      ExpressionStatement(BuiltIn("DICE", [ID("x")])),
+      ExpressionStatement(BuiltIn("DICE", [ID("y")])),
+    ]),
+    ValStr("II"),
+    "V\nII\n",
+  ),
+]
+
+class TestDestructuring(unittest.TestCase):
+  @parameterized.expand(destructuring_tests)
+  def test_destructuring(self, source, nodes, value, output=""):
+    run_test(self, source, nodes, value, output)
+
+
 # --- Control flow ---
 
 control_tests = [
@@ -460,6 +536,37 @@ builtin_tests = [
   ('LONGITVDO("salve")', Program([], [ExpressionStatement(BuiltIn("LONGITVDO", [String("salve")]))]), ValInt(5)),
   ('LONGITVDO("")', Program([], [ExpressionStatement(BuiltIn("LONGITVDO", [String("")]))]), ValInt(0)),
   ("CVM FORS\nFORTIS_ELECTIONIS([I, II, III])", Program([ModuleCall("FORS")], [ExpressionStatement(BuiltIn("FORTIS_ELECTIONIS", [DataArray([Numeral("I"), Numeral("II"), Numeral("III")])]))]), ValInt(1)),
+  ("CVM FORS\nSEMEN(XLII)\nFORTIS_NVMERVS(I, C)", Program([ModuleCall("FORS")], [ExpressionStatement(BuiltIn("SEMEN", [Numeral("XLII")])), ExpressionStatement(BuiltIn("FORTIS_NVMERVS", [Numeral("I"), Numeral("C")]))]), ValInt(82)),
+  # DECIMATIO: seed 42, 10 elements → removes 1 (element II)
+  ("CVM FORS\nSEMEN(XLII)\nDECIMATIO([I, II, III, IV, V, VI, VII, VIII, IX, X])", Program([ModuleCall("FORS")], [ExpressionStatement(BuiltIn("SEMEN", [Numeral("XLII")])), ExpressionStatement(BuiltIn("DECIMATIO", [DataArray([Numeral("I"), Numeral("II"), Numeral("III"), Numeral("IV"), Numeral("V"), Numeral("VI"), Numeral("VII"), Numeral("VIII"), Numeral("IX"), Numeral("X")])]))]), ValList([ValInt(1), ValInt(3), ValInt(4), ValInt(5), ValInt(6), ValInt(7), ValInt(8), ValInt(9), ValInt(10)])),
+  # DECIMATIO: seed 1, 3 elements → 3//10=0, nothing removed
+  ("CVM FORS\nSEMEN(I)\nDECIMATIO([I, II, III])", Program([ModuleCall("FORS")], [ExpressionStatement(BuiltIn("SEMEN", [Numeral("I")])), ExpressionStatement(BuiltIn("DECIMATIO", [DataArray([Numeral("I"), Numeral("II"), Numeral("III")])]))]), ValList([ValInt(1), ValInt(2), ValInt(3)])),
+  # DECIMATIO: empty array → empty array
+  ("CVM FORS\nDECIMATIO([])", Program([ModuleCall("FORS")], [ExpressionStatement(BuiltIn("DECIMATIO", [DataArray([])]))]), ValList([])),
+  # DECIMATIO: seed 42, 20 elements → removes 2 (elements I and IV)
+  ("CVM FORS\nSEMEN(XLII)\nDECIMATIO([I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX, XX])", Program([ModuleCall("FORS")], [ExpressionStatement(BuiltIn("SEMEN", [Numeral("XLII")])), ExpressionStatement(BuiltIn("DECIMATIO", [DataArray([Numeral("I"), Numeral("II"), Numeral("III"), Numeral("IV"), Numeral("V"), Numeral("VI"), Numeral("VII"), Numeral("VIII"), Numeral("IX"), Numeral("X"), Numeral("XI"), Numeral("XII"), Numeral("XIII"), Numeral("XIV"), Numeral("XV"), Numeral("XVI"), Numeral("XVII"), Numeral("XVIII"), Numeral("XIX"), Numeral("XX")])]))]), ValList([ValInt(2), ValInt(3), ValInt(5), ValInt(6), ValInt(7), ValInt(8), ValInt(9), ValInt(10), ValInt(11), ValInt(12), ValInt(13), ValInt(14), ValInt(15), ValInt(16), ValInt(17), ValInt(18), ValInt(19), ValInt(20)])),
+  # SENATVS: majority true → VERITAS
+  ("SENATVS(VERITAS, VERITAS, FALSITAS)", Program([], [ExpressionStatement(BuiltIn("SENATVS", [Bool(True), Bool(True), Bool(False)]))]), ValBool(True)),
+  # SENATVS: majority false → FALSITAS
+  ("SENATVS(FALSITAS, FALSITAS, VERITAS)", Program([], [ExpressionStatement(BuiltIn("SENATVS", [Bool(False), Bool(False), Bool(True)]))]), ValBool(False)),
+  # SENATVS: tie → FALSITAS
+  ("SENATVS(VERITAS, FALSITAS)", Program([], [ExpressionStatement(BuiltIn("SENATVS", [Bool(True), Bool(False)]))]), ValBool(False)),
+  # SENATVS: 4-arg tie → FALSITAS
+  ("SENATVS(VERITAS, VERITAS, FALSITAS, FALSITAS)", Program([], [ExpressionStatement(BuiltIn("SENATVS", [Bool(True), Bool(True), Bool(False), Bool(False)]))]), ValBool(False)),
+  # SENATVS: single true → VERITAS
+  ("SENATVS(VERITAS)", Program([], [ExpressionStatement(BuiltIn("SENATVS", [Bool(True)]))]), ValBool(True)),
+  # SENATVS: single false → FALSITAS
+  ("SENATVS(FALSITAS)", Program([], [ExpressionStatement(BuiltIn("SENATVS", [Bool(False)]))]), ValBool(False)),
+  # SENATVS: empty → FALSITAS (vacuous)
+  ("SENATVS()", Program([], [ExpressionStatement(BuiltIn("SENATVS", []))]), ValBool(False)),
+  # SENATVS: all true <20><> VERITAS
+  ("SENATVS(VERITAS, VERITAS, VERITAS, VERITAS, VERITAS)", Program([], [ExpressionStatement(BuiltIn("SENATVS", [Bool(True), Bool(True), Bool(True), Bool(True), Bool(True)]))]), ValBool(True)),
+  # SENATVS: array input, majority true → VERITAS
+  ("SENATVS([VERITAS, VERITAS, FALSITAS])", Program([], [ExpressionStatement(BuiltIn("SENATVS", [DataArray([Bool(True), Bool(True), Bool(False)])]))]), ValBool(True)),
+  # SENATVS: array input, majority false → FALSITAS
+  ("SENATVS([FALSITAS, FALSITAS, VERITAS])", Program([], [ExpressionStatement(BuiltIn("SENATVS", [DataArray([Bool(False), Bool(False), Bool(True)])]))]), ValBool(False)),
+  # SENATVS: array input, empty → FALSITAS
+  ("SENATVS([])", Program([], [ExpressionStatement(BuiltIn("SENATVS", [DataArray([])]))]), ValBool(False)),
 ]
 
 class TestBuiltins(unittest.TestCase):
@@ -494,11 +601,18 @@ error_tests = [
   ("\"hello\" MINVS \"world\"", CentvrionError),                       # comparison with strings
   ("I[I]", CentvrionError),                                           # indexing a non-array
   ("DESIGNA x VT I\nDESIGNA x[I] VT II", CentvrionError),             # index-assign to non-array
+  ("SEMEN(I)", CentvrionError),                                        # requires FORS module
+  ('CVM FORS\nSEMEN("abc")', CentvrionError),                          # SEMEN requires integer seed
   ("FORTIS_ELECTIONIS([])", CentvrionError),                           # FORS required for FORTIS_ELECTIONIS
   ("CVM FORS\nFORTIS_ELECTIONIS([])", CentvrionError),                 # FORTIS_ELECTIONIS on empty array
   ("CVM FORS\nFORTIS_NVMERVS(X, I)", CentvrionError),                  # FORTIS_NVMERVS a > b
   ("PER i IN I FACE { DICE(i) }", CentvrionError),                     # PER over non-array
+  ("DECIMATIO([I, II, III])", CentvrionError),                          # FORS required for DECIMATIO
+  ("CVM FORS\nDECIMATIO(I)", CentvrionError),                          # DECIMATIO requires an array
   ("LONGITVDO(I)", CentvrionError),                                    # LONGITVDO on non-array
+  ("SENATVS(I)", CentvrionError),                                      # SENATVS requires booleans
+  ("SENATVS(VERITAS, I)", CentvrionError),                             # SENATVS mixed types
+  ("SENATVS([I, II, III])", CentvrionError),                           # SENATVS array of non-bools
   ("DESIGNA x VT I\nINVOCA x ()", CentvrionError),                     # invoking a non-function
   ("SI I TVNC { DESIGNA r VT I }", CentvrionError),                    # non-bool SI condition: int
   ("IIIS", CentvrionError),                                            # fraction without FRACTIO module
@@ -511,6 +625,9 @@ error_tests = [
   ("NON I", CentvrionError),                                               # NON on integer
   ("DESIGNA z VT I - I\nNON z", CentvrionError),                          # NON on zero integer
   ('NON "hello"', CentvrionError),                                         # NON on string
+  ("DESIGNA a, b VT III", CentvrionError),                                 # destructure non-array
+  ("DESIGNA a, b VT [I]", CentvrionError),                                # destructure length mismatch: too many targets
+  ("DESIGNA a, b VT [I, II, III]", CentvrionError),                       # destructure length mismatch: too few targets
 ]
 
 class TestErrors(unittest.TestCase):

vscode-extension/syntaxes/cent.tmLanguage.json

@@ -65,7 +65,7 @@
 			"patterns": [
 				{
 					"name": "support.function.builtin.cent",
-					"match": "\\b(AVDI_NVMERVS|AVDI|DICE|EVERRO|FORTIS_NVMERVS|FORTIS_ELECTIONIS|LONGITVDO)\\b"
+					"match": "\\b(AVDI_NVMERVS|AVDI|DECIMATIO|DICE|EVERRO|FORTIS_NVMERVS|FORTIS_ELECTIONIS|LONGITVDO|SEMEN)\\b"
 				}
 			]
 		},