hyperpolymath · hyperpolymath · May 18, 2026 · May 18, 2026
diff --git a/affinescript-deno-test/example/codegen_regression_test.affine b/affinescript-deno-test/example/codegen_regression_test.affine
@@ -40,7 +40,7 @@ fn advance(s: Lifecycle) -> Lifecycle {
 }
 
 fn make_counters() -> Counters {
-  { tag: 1, profile_id: 42, activity_count: 7 }
+  #{ tag: 1, profile_id: 42, activity_count: 7 }
 }
 
 fn read_profile_id(c: Counters) -> Int {

diff --git a/conformance/valid/011_rows.affine b/conformance/valid/011_rows.affine
@@ -9,7 +9,7 @@ fn get_name[..r](entity: {name: String, ..r}) -> String {
 }
 
 fn with_id[..r](record: {..r}, id: Int) -> {id: Int, ..r} {
-  { id: id, ..record }
+  #{ id: id, ..record }
 }
 
 type HasPosition[..r] = {x: Int, y: Int, ..r}

diff --git a/examples/comprehensive_test.affine b/examples/comprehensive_test.affine
@@ -12,7 +12,7 @@ enum Shape {
 }
 
 fn vec2_add(a: Vec2, b: Vec2) -> Vec2 {
-  { x: a.x + b.x, y: a.y + b.y }
+  #{ x: a.x + b.x, y: a.y + b.y }
 }
 
 fn area(s: Shape) -> Int {
@@ -30,7 +30,7 @@ fn larger_area(s1: Shape, s2: Shape) -> Int = max(area(s1), area(s2));
 
 fn main() -> () {
   let circle = Circle(5);
-  let rect = Rect({ x: 3, y: 4 });
+  let rect = Rect(#{ x: 3, y: 4 });
   let result = larger_area(circle, rect);
   ();
 }
diff --git a/examples/rows.affine b/examples/rows.affine
@@ -15,5 +15,5 @@ struct Point3D {
 fn getX(p: Point2D) -> Int = p.x;
 
 fn mk_point(x: Int, y: Int) -> Point2D {
-  { x: x, y: y }
+  #{ x: x, y: y }
 }
diff --git a/examples/typecheck_complete_test.affine b/examples/typecheck_complete_test.affine
@@ -15,11 +15,11 @@ enum Color {
 }
 
 fn make_point(x: Int, y: Int) -> Point {
-  { x: x, y: y }
+  #{ x: x, y: y }
 }
 
 fn origin() -> Point {
-  { x: 0, y: 0 }
+  #{ x: 0, y: 0 }
 }
 
 fn mutate_counter() -> Int {

diff --git a/lib/lexer.ml b/lib/lexer.ml
@@ -183,6 +183,9 @@ let rec token state buf =
   | "-=" -> MINUSEQ
   | "*=" -> STAREQ
   | "/=" -> SLASHEQ
+  (* `#{` opens a record/struct literal (#218); longest-match, and `#` has
+     no other lexer rule, so this never shadows a single-char token. *)
+  | "#{" -> HASH_LBRACE
 
   (* Single-char tokens *)
   | '(' -> LPAREN

diff --git a/lib/parse_driver.ml b/lib/parse_driver.ml
@@ -76,6 +76,7 @@ let to_menhir_token (tok : Token.t) : Parser.token =
     | Token.LPAREN -> Parser.LPAREN
     | Token.RPAREN -> Parser.RPAREN
     | Token.LBRACE -> Parser.LBRACE
+    | Token.HASH_LBRACE -> Parser.HASH_LBRACE
     | Token.RBRACE -> Parser.RBRACE
     | Token.LBRACKET -> Parser.LBRACKET
     | Token.RBRACKET -> Parser.RBRACKET

diff --git a/lib/parser.mly b/lib/parser.mly
@@ -66,6 +66,10 @@ let rec effect_union_of_list = function
 
 /* Punctuation */
 %token LPAREN RPAREN LBRACE RBRACE LBRACKET RBRACKET
+/* `#{` opens a record/struct literal (#218). `{` is ALWAYS a block in
+   expression position — this structurally removes the block-vs-record
+   ambiguity (#215 families C+D) with no lookahead heuristic. */
+%token HASH_LBRACE
 %token COMMA SEMICOLON COLON COLONCOLON DOT DOTDOT
 %token ARROW FAT_ARROW PIPE AT UNDERSCORE BACKSLASH QUESTION
 
@@ -768,10 +772,10 @@ expr_primary:
      ordinary parameter binding named "self". */
   | SELF_KW { ExprVar (mk_ident "self" $startpos $endpos) }
   | name = lower_ident { ExprVar (mk_ident name $startpos $endpos) }
-  /* Struct literal: `Point { x: v, y: w }`.  Must come before the plain
-     upper_ident production so Menhir shifts LBRACE rather than reducing
-     upper_ident to ExprVar when the next token is LBRACE. */
-  | _ty = upper_ident LBRACE b = expr_record_body RBRACE
+  /* Struct literal: `Point #{ x: v, y: w }` (#218).  The `#{` sigil makes
+     this unambiguous against the plain `upper_ident` production and against
+     a following block, so no LBRACE-shift heuristic is needed any more. */
+  | _ty = upper_ident HASH_LBRACE b = expr_record_body RBRACE
     { ExprRecord { er_fields = fst b; er_spread = snd b } }
   | name = upper_ident { ExprVar (mk_ident name $startpos $endpos) }
   | ty = upper_ident COLONCOLON variant = upper_ident
@@ -787,11 +791,12 @@ expr_primary:
   /* Arrays */
   | LBRACKET es = separated_list(COMMA, expr) RBRACKET { ExprArray es }
 
-  /* Records — use a recursive rule (expr_record_body / expr_record_rest) to
-     avoid the LALR(1) greedy-separator conflict that arises when a ROW_VAR
-     spread like `..record` follows a COMMA that `separated_list` has already
-     consumed expecting another record_field. */
-  | LBRACE b = expr_record_body RBRACE
+  /* Anonymous record `#{ f: v, ..spread }` (#218).  Uses a recursive rule
+     (expr_record_body / expr_record_rest) to avoid the LALR(1) greedy-
+     separator conflict that arises when a ROW_VAR spread like `..record`
+     follows a COMMA that `separated_list` has already consumed expecting
+     another record_field. */
+  | HASH_LBRACE b = expr_record_body RBRACE
     { ExprRecord { er_fields = fst b; er_spread = snd b } }
 
   /* Block */

diff --git a/lib/token.ml b/lib/token.ml
@@ -72,6 +72,7 @@ type t =
   | LPAREN
   | RPAREN
   | LBRACE
+  | HASH_LBRACE
   | RBRACE
   | LBRACKET
   | RBRACKET
@@ -186,6 +187,7 @@ let to_string = function
   | LPAREN -> "("
   | RPAREN -> ")"
   | LBRACE -> "{"
+  | HASH_LBRACE -> "#{"
   | RBRACE -> "}"
   | LBRACKET -> "["
   | RBRACKET -> "]"

diff --git a/stdlib/testing.affine b/stdlib/testing.affine
@@ -303,7 +303,7 @@ fn bench(f: () -> (), iterations: Int) -> BenchResult {
   }
 
   let tot = time_now() - start;
-  {
+  #{
     iterations: iterations,
     total_time: tot,
     avg_time: tot / float(iterations)

diff --git a/test/e2e/fixtures/counter.affine b/test/e2e/fixtures/counter.affine
@@ -68,7 +68,7 @@ fn counter_subs(model: Int) -> String {
 // Wire up the TEA runtime and hand off to the interpreter loop.
 
 fn main() -> () {
-  tea_run({
+  tea_run(#{
     init:          counter_init,
     update:        counter_update,
     view:          counter_view,

diff --git a/test/e2e/fixtures/full_pipeline.affine b/test/e2e/fixtures/full_pipeline.affine
@@ -13,7 +13,7 @@ enum Shape {
 }
 
 fn vec2_add(a: Vec2, b: Vec2) -> Vec2 {
-  { x: a.x + b.x, y: a.y + b.y }
+  #{ x: a.x + b.x, y: a.y + b.y }
 }
 
 fn area(s: Shape) -> Int {
@@ -31,7 +31,7 @@ fn larger_area(s1: Shape, s2: Shape) -> Int = max(area(s1), area(s2));
 
 fn main() -> () {
   let circle = Circle(5);
-  let rect = Rect({ x: 3, y: 4 });
+  let rect = Rect(#{ x: 3, y: 4 });
   let result = larger_area(circle, rect);
   ();
 }
diff --git a/test/e2e/fixtures/row_polymorphism.affine b/test/e2e/fixtures/row_polymorphism.affine
@@ -16,5 +16,5 @@ struct Point3D {
 fn getX(p: Point2D) -> Int = p.x;
 
 fn mk_point(x: Int, y: Int) -> Point2D {
-  { x: x, y: y }
+  #{ x: x, y: y }
 }
diff --git a/test/e2e/fixtures/titlescreen.affine b/test/e2e/fixtures/titlescreen.affine
@@ -44,7 +44,7 @@ struct TitleModel {
 // ── init ─────────────────────────────────────────────────────────────────────
 
 fn title_init() -> TitleModel {
-  {
+  #{
     screen_w:    1280,
     screen_h:    720,
     bgm_playing: 0,
@@ -58,10 +58,10 @@ fn title_init() -> TitleModel {
 
 fn title_update(msg: TitleMsg, model: TitleModel) -> TitleModel {
   match msg {
-    NewGame  => { screen_w: model.screen_w, screen_h: model.screen_h, bgm_playing: model.bgm_playing, selected: "new_game" },
-    LoadGame => { screen_w: model.screen_w, screen_h: model.screen_h, bgm_playing: model.bgm_playing, selected: "load_game" },
-    Settings => { screen_w: model.screen_w, screen_h: model.screen_h, bgm_playing: model.bgm_playing, selected: "settings" },
-    Credits  => { screen_w: model.screen_w, screen_h: model.screen_h, bgm_playing: model.bgm_playing, selected: "credits" }
+    NewGame  => #{ screen_w: model.screen_w, screen_h: model.screen_h, bgm_playing: model.bgm_playing, selected: "new_game" },
+    LoadGame => #{ screen_w: model.screen_w, screen_h: model.screen_h, bgm_playing: model.bgm_playing, selected: "load_game" },
+    Settings => #{ screen_w: model.screen_w, screen_h: model.screen_h, bgm_playing: model.bgm_playing, selected: "settings" },
+    Credits  => #{ screen_w: model.screen_w, screen_h: model.screen_h, bgm_playing: model.bgm_playing, selected: "credits" }
   }
 }
 
@@ -84,7 +84,7 @@ fn title_subs(model: TitleModel) -> String {
 // ── main ──────────────────────────────────────────────────────────────────────
 
 fn main() -> () {
-  tea_run({
+  tea_run(#{
     init:          title_init,
     update:        title_update,
     view:          title_view,

diff --git a/test/e2e/fixtures/type_decls.affine b/test/e2e/fixtures/type_decls.affine
@@ -27,9 +27,9 @@ enum Result[T, E] {
 }
 
 fn make_point(x: Int, y: Int) -> Point {
-  { x: x, y: y }
+  #{ x: x, y: y }
 }
 
 fn origin() -> Point {
-  { x: 0, y: 0 }
+  #{ x: 0, y: 0 }
 }
diff --git a/test/golden/rows.affine b/test/golden/rows.affine
@@ -4,5 +4,5 @@ fn getX[..r](p: {x: Int, ..r}) -> Int {
 }
 
 fn addY[..r](p: {..r}) -> {y: Int, ..r} {
-  {y: 0, ..p}
+  #{y: 0, ..p}
 }
diff --git a/tests/borrow/test_move.affine b/tests/borrow/test_move.affine
@@ -43,14 +43,14 @@ fn test_add_two_negatives() -> TestResult {
 
 /// Run all add conformance tests
 fn test_alib_arithmetic_add() -> TestResult {
-  let suite = {
+  let suite = #{
     name: "aLib arithmetic/add conformance",
     tests: [
-      { name: "add_positive", test: test_add_positive },
-      { name: "add_negative", test: test_add_negative },
-      { name: "add_zeros", test: test_add_zeros },
-      { name: "add_decimal", test: test_add_decimal },
-      { name: "add_two_negatives", test: test_add_two_negatives }
+      #{ name: "add_positive", test: test_add_positive },
+      #{ name: "add_negative", test: test_add_negative },
+      #{ name: "add_zeros", test: test_add_zeros },
+      #{ name: "add_decimal", test: test_add_decimal },
+      #{ name: "add_two_negatives", test: test_add_two_negatives }
     ]
   };
 

diff --git a/tests/codegen/test_pattern_record.affine b/tests/codegen/test_pattern_record.affine
@@ -1,7 +1,7 @@
 // Test record pattern matching
 
 fn main() -> Int {
-  let r = {x: 10, y: 20};
+  let r = #{x: 10, y: 20};
 
   let result = match r {
     {x: a, y: b} => a + b

diff --git a/tests/codegen/test_record_multi_field.affine b/tests/codegen/test_record_multi_field.affine
@@ -1,6 +1,6 @@
 // Test record with multiple fields
 
 fn main() -> Int {
-  let r = {x: 10, y: 20, z: 30};
+  let r = #{x: 10, y: 20, z: 30};
   return r.x + r.y + r.z;  // Should return 60
 }
diff --git a/tests/codegen/test_record_multiple.affine b/tests/codegen/test_record_multiple.affine
@@ -1,8 +1,8 @@
 // Test multiple distinct records
 
 fn main() -> Int {
-  let r1 = {a: 5, b: 10};
-  let r2 = {x: 20, y: 30, z: 40};
+  let r1 = #{a: 5, b: 10};
+  let r2 = #{x: 20, y: 30, z: 40};
 
   return r1.a + r1.b + r2.x + r2.y + r2.z;  // 5 + 10 + 20 + 30 + 40 = 105
 }
diff --git a/tests/codegen/test_record_simple.affine b/tests/codegen/test_record_simple.affine
@@ -1,6 +1,6 @@
 // Test simple record construction and field access
 
 fn main() -> Int {
-  let r = {x: 42};
+  let r = #{x: 42};
   return r.x;  // Should return 42
 }
diff --git a/tests/codegen/test_tuple_record_array.affine b/tests/codegen/test_tuple_record_array.affine
@@ -3,7 +3,7 @@
 type Point = { x: Int, y: Int, z: Int };
 
 fn main() -> Int {
-  let p = { x: 10, y: 20, z: 30 };
+  let p = #{ x: 10, y: 20, z: 30 };
   let t = (1, 2, 3, 4);
   let a = [5, 6];
   return p.x + p.y + p.z + t.0 + t.1 + t.2 + t.3 + a[0] + a[1];

diff --git a/tests/conformance/arithmetic/add.affine b/tests/conformance/arithmetic/add.affine
@@ -43,14 +43,14 @@ fn test_add_two_negatives() -> TestResult {
 
 /// Run all add conformance tests
 fn test_alib_arithmetic_add() -> TestResult {
-  let suite = {
+  let suite = #{
     name: "aLib arithmetic/add conformance",
     tests: [
-      { name: "add_positive", test: test_add_positive },
-      { name: "add_negative", test: test_add_negative },
-      { name: "add_zeros", test: test_add_zeros },
-      { name: "add_decimal", test: test_add_decimal },
-      { name: "add_two_negatives", test: test_add_two_negatives }
+      #{ name: "add_positive", test: test_add_positive },
+      #{ name: "add_negative", test: test_add_negative },
+      #{ name: "add_zeros", test: test_add_zeros },
+      #{ name: "add_decimal", test: test_add_decimal },
+      #{ name: "add_two_negatives", test: test_add_two_negatives }
     ]
   };
 

diff --git a/tests/conformance/arithmetic/divide.affine b/tests/conformance/arithmetic/divide.affine
@@ -50,15 +50,15 @@ fn test_divide_two_negatives() -> TestResult {
 
 /// Run all divide conformance tests
 fn test_alib_arithmetic_divide() -> TestResult {
-  let suite = {
+  let suite = #{
     name: "aLib arithmetic/divide conformance",
     tests: [
-      { name: "divide_exact", test: test_divide_exact },
-      { name: "divide_fractional", test: test_divide_fractional },
-      { name: "divide_zero", test: test_divide_zero },
-      { name: "divide_negative_dividend", test: test_divide_negative_dividend },
-      { name: "divide_negative_divisor", test: test_divide_negative_divisor },
-      { name: "divide_two_negatives", test: test_divide_two_negatives }
+      #{ name: "divide_exact", test: test_divide_exact },
+      #{ name: "divide_fractional", test: test_divide_fractional },
+      #{ name: "divide_zero", test: test_divide_zero },
+      #{ name: "divide_negative_dividend", test: test_divide_negative_dividend },
+      #{ name: "divide_negative_divisor", test: test_divide_negative_divisor },
+      #{ name: "divide_two_negatives", test: test_divide_two_negatives }
     ]
   };
 

diff --git a/tests/conformance/arithmetic/modulo.affine b/tests/conformance/arithmetic/modulo.affine
@@ -43,14 +43,14 @@ fn test_modulo_large() -> TestResult {
 
 /// Run all modulo conformance tests
 fn test_alib_arithmetic_modulo() -> TestResult {
-  let suite = {
+  let suite = #{
     name: "aLib arithmetic/modulo conformance",
     tests: [
-      { name: "modulo_basic", test: test_modulo_basic },
-      { name: "modulo_no_remainder", test: test_modulo_no_remainder },
-      { name: "modulo_nonzero", test: test_modulo_nonzero },
-      { name: "modulo_zero", test: test_modulo_zero },
-      { name: "modulo_large", test: test_modulo_large }
+      #{ name: "modulo_basic", test: test_modulo_basic },
+      #{ name: "modulo_no_remainder", test: test_modulo_no_remainder },
+      #{ name: "modulo_nonzero", test: test_modulo_nonzero },
+      #{ name: "modulo_zero", test: test_modulo_zero },
+      #{ name: "modulo_large", test: test_modulo_large }
     ]
   };
 

diff --git a/tests/conformance/arithmetic/multiply.affine b/tests/conformance/arithmetic/multiply.affine
@@ -50,15 +50,15 @@ fn test_multiply_two_negatives() -> TestResult {
 
 /// Run all multiply conformance tests
 fn test_alib_arithmetic_multiply() -> TestResult {
-  let suite = {
+  let suite = #{
     name: "aLib arithmetic/multiply conformance",
     tests: [
-      { name: "multiply_positive", test: test_multiply_positive },
-      { name: "multiply_negative", test: test_multiply_negative },
-      { name: "multiply_zero", test: test_multiply_zero },
-      { name: "multiply_identity", test: test_multiply_identity },
-      { name: "multiply_decimal", test: test_multiply_decimal },
-      { name: "multiply_two_negatives", test: test_multiply_two_negatives }
+      #{ name: "multiply_positive", test: test_multiply_positive },
+      #{ name: "multiply_negative", test: test_multiply_negative },
+      #{ name: "multiply_zero", test: test_multiply_zero },
+      #{ name: "multiply_identity", test: test_multiply_identity },
+      #{ name: "multiply_decimal", test: test_multiply_decimal },
+      #{ name: "multiply_two_negatives", test: test_multiply_two_negatives }
     ]
   };