Phase 4b: enum types name magic-int value spaces

enum Name { A, B, C } declares named int constants; Enum.Variant is a
compile-time int (index by declaration order), usable in match patterns,
comparisons, setreg. New: parse_enum + dispatch, enum_ordinal resolver
(emit_core), Enum.Variant handling (emit_expr). Scoped to a naming layer over
int (no enum-typed variables), so register/save semantics are untouched.

combat.ludic battle menus dispatch on KnightAct/MageAct instead of 0..3;
chronorift golden byte-identical. Editor vocab (ludic_syntax.h, JetBrains,
TextMate, emacs) gained enum, dropped retired edge/export/pure decl keywords;
check-vocabulary + test-tools 28/0. when/if kept by choice; bitwise stays
functions. Reseeded, fixpoint holds, test.sh 14/14.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

LANGUAGE.md

@@ -392,6 +392,26 @@ is still accepted when a state needs a specific value.) A `machine <reg>` reads
 value>)`. Both lower to plain branches (and `match` runs on the native LLVM
 backend too).
 
+## Enums
+
+`enum` names a set of related integer values so a magic-number space — a menu
+selection, a mode, a machine state — reads as names instead of literals:
+
+```ludic
+# doc-check: skip — composite: a declaration plus its uses
+enum Action { Attack, Guard, Item, Flee }        # Attack = 0, Guard = 1, …
+
+match reg(R_CUR) { Action.Attack => attack()  Action.Guard => guard()  _ => wait() }
+if reg(R_MODE) == Mode.Battle { … }
+```
+
+A variant is a **compile-time `int`** accessed as `Enum.Variant` (`Action.Guard`
+is `1`), numbered from `0` by declaration order, so it works anywhere an int does
+— `match` patterns, comparisons, `setreg`. Enums are a naming layer over `int`:
+there is no distinct enum runtime type yet, so an enum value lives in an ordinary
+`int` or register (and is saved with it). See `examples/chronorift/combat.ludic`,
+whose battle menus dispatch on `KnightAct`/`MageAct` instead of `0..3`.
+
 ## Expressions
 
 Precedence: `or → and → compar(< <= > >= == !=) → + - → * / % → unary(- not) →

SYNTAX-REDESIGN.md

@@ -48,9 +48,9 @@ Verified against the self-hosted compiler ([selfhost/parse.ludic](selfhost/parse
 11. Operators are words (`and`/`or`/`not`), symbols (`==`/`<=`), *and* functions
     (`band`/`shl`) at once.
 12. Three overlapping control families — `if`/`when`, `match`, `machine`/`become`
-    — and `enter` reuses `become`'s AST node ([parse.ludic:176-177](selfhost/parse.ludic)).
+    — and `enter` reuses `become`'s AST node ([parse.ludic:176-177](selfhost/parse.ludic)). *(Phase 4: `if`/`when` kept by choice; magic-int dispatch resolved)*
 13. Typed components/structs exist, but real state lives in 64 untyped int
-    registers (`reg`/`setreg`), so `machine`/`match` dispatch on magic numbers.
+    registers (`reg`/`setreg`), so `machine`/`match` dispatch on magic numbers. *(✅ Phase 4: auto-numbered states + `enum` name the values)*
 
 ---
 
@@ -285,13 +285,36 @@ migration (IR byte-identical / goldens identical) → reseed → docs. The migra
 tools ([migrate_separators.c](tools/ludic-tools/migrate_separators.c),
 [migrate_records.c](tools/ludic-tools/migrate_records.c)) are the reusable spine.
 
-### Phase 4 — Control-flow & operator consolidation (largest)
-- Remove `when`; confirm `if` covers all uses in the corpus.
-- Introduce `enum` + typed `machine`/state; migrate `combat.ludic`'s R_PHASE
-  machine and the register-driven `match reg(…)` sites.
-- Decide the bitwise story: keep `band/shl/…` as functions (document as a
-  deliberate "one spelling" choice) or promote to operators — pick one and state
-  it, don't leave it implicit.
+### Phase 4 — Control-flow & state consolidation
+
+**4a — machine states auto-number ✅ DONE.** `state KnightMenu = 0 { }` →
+`state KnightMenu { }`; a state's value is its declaration index (an explicit
+`= expr` still works). Removes the magic constants from state machines
+([parse.ludic](selfhost/parse.ludic)). combat.ludic migrated; chronorift golden
+byte-identical.
+
+**4b — `enum` types ✅ DONE.** `enum Action { Attack, Guard, Item, Flee }` declares
+named `int` constants; a variant is a compile-time int accessed as `Action.Guard`
+(= 1), numbered by order. Parser `parse_enum` + dispatch, `enum_ordinal` resolver
+in [emit_core.ludic](selfhost/emit_core.ludic), and `Enum.Variant` handling in
+[emit_expr.ludic](selfhost/emit_expr.ludic). combat.ludic's battle menus now
+dispatch on `KnightAct`/`MageAct` instead of `0..3`; chronorift golden
+byte-identical. Editor vocab (`ludic_syntax.h`, JetBrains, TextMate, emacs) gained
+`enum` and lost the retired `edge`/`export`/`pure` decl keywords; check-vocabulary
++ test-tools green. **Scoped:** enums are a naming layer over `int` (no distinct
+runtime type / enum-typed variables yet) — that keeps register/save semantics
+untouched, which the "enum var replaces the register" vision would have to solve.
+
+**`when` vs `if` — kept both (decision).** `when` stays as the `if`-without-else
+spelling: it is not incoherent so much as a readability signal ("no else here"),
+it is documented and highlighted, and it is a pure alias with no semantic overlap
+to untangle. The real target of finding #12 — dispatch on magic integers — is
+addressed by 4a/4b, not by collapsing `if`/`when`.
+
+**Bitwise operators — kept as functions (decision).** `band`/`bor`/`bxor`/`bnot`/
+`shl`/`shr` stay functions, documented as the deliberate "one spelling, symbols
+stay free" choice (LANGUAGE.md §Expressions already states this). Promoting them
+to operators would re-introduce the symbol soup the current design avoids.
 
 ### Phase 5 — Single source of truth for keywords/grammar
 - Generate every editor plugin keyword list, `ludic_syntax.h`, and the LSP's

examples/chronorift/combat.ludic

@@ -3,6 +3,11 @@
 # The battle is a state machine over R_PHASE. `machine` dispatches on the
 # register and `become` transitions to a named state — no more `if ph == N`
 # ladders. Knight turn (0,1), Mage turn (2,3), Enemy turn (4).
+
+# Menu selections, named instead of matched on bare integers (R_CUR holds one).
+enum KnightAct { Attack, Guard, Item, Flee }
+enum MageAct   { Attack, Heal, Guard }
+
 system Battle phase Update {
   if reg(R_MODE) == 1 {
     let k = key()
@@ -20,20 +25,20 @@ system Battle phase Update {
                 if k == 's' { setreg(R_CUR, min(3, reg(R_CUR) + 1)) }
                 if is_confirm(k) {
                   match reg(R_CUR) {
-                    0 => {
+                    KnightAct.Attack => {
                       let d = max(1, st.atk - e.def + rng_range(0, 4))
                       e.hp = e.hp - d
                       setreg(R_PDMG, d)
                     }
-                    1 => { st.guard = 1;  setreg(R_PDMG, 0) }
-                    2 => {
+                    KnightAct.Guard => { st.guard = 1;  setreg(R_PDMG, 0) }
+                    KnightAct.Item => {
                       if reg(R_POTION) > 0 {
                         setreg(R_POTION, reg(R_POTION) - 1)
                         st.hp = min(st.maxhp, st.hp + 24)
                         setreg(R_PDMG, 24)
                       } else { setreg(R_PDMG, 0) }
                     }
-                    3 => {
+                    KnightAct.Flee => {
                       if rng_chance(50) { e.hp = 0;  setreg(R_MODE, 0) }
                       else { setreg(R_PDMG, 0) }
                     }
@@ -71,12 +76,12 @@ system Battle phase Update {
                 if k == 'k' { setreg(R_CUR, min(2, reg(R_CUR) + 1)) }
                 if k == 'j' {
                   match reg(R_CUR) {
-                    0 => {
+                    MageAct.Attack => {
                       let d = max(1, st.atk + 5 - e.def + rng_range(0, 5))
                       e.hp = e.hp - d
                       setreg(R_PDMG, d)
                     }
-                    1 => {
+                    MageAct.Heal => {
                       if st.mp >= 4 {
                         st.mp = st.mp - 4
                         for (t2, p2) in query [Stats, Party] {
@@ -85,7 +90,7 @@ system Battle phase Update {
                         setreg(R_PDMG, 16)
                       } else { setreg(R_PDMG, 0) }
                     }
-                    2 => { st.guard = 1;  setreg(R_PDMG, 0) }
+                    MageAct.Guard => { st.guard = 1;  setreg(R_PDMG, 0) }
                   }
                   become MageResolve
                   setreg(R_CUR, 0)

selfhost/ast.ludic

@@ -15,6 +15,7 @@ const N_SYS:    int = 9
 const N_ARCH:   int = 10
 const N_EXTERN: int = 11
 const N_UI:     int = 12
+const N_ENUM:   int = 27         # enum Name { A, B, ... } — named int constants
 # statements
 const S_LET:      int = 10
 const S_ASSIGN:   int = 11

selfhost/emit_core.ludic

@@ -119,6 +119,21 @@ fn find_global(name: ptr) -> Node {
   }
   return ptr_null()
 }
+
+# `Enum.Variant` -> the variant's ordinal (its index), or -1 if `ename` names no
+# enum with that variant. Enum names live in `prog` like any other declaration.
+fn enum_ordinal(ename: ptr, vname: ptr) -> int {
+  let i = 0
+  while i < len(prog) {
+    let d = prog[i]
+    if d.kind == N_ENUM and streq(d.s, ename) {
+      let j = 0
+      while j < len(d.kids) { if streq(d.kids[j].s, vname) { return j };  j = j + 1 }
+    }
+    i = i + 1
+  }
+  return 0 - 1
+}
 fn find_fn(name: ptr) -> Node {
   let i = 0
   while i < len(prog) { let d = prog[i];  if d.kind == N_FN and streq(d.s, name) { return d };  i = i + 1 }

selfhost/emit_expr.ludic

@@ -152,7 +152,13 @@ fn emit_expr(e: Node) -> Val {
     if is_ui_ident(e.s) { return val(itoa(ui_index_of(e.s)), "int") }
     perr(sconcat("unknown identifier ", e.s))
   }
-  if e.kind == E_MEMBER { let a = emit_member_addr(e);  return emit_load_at(a, g_addr_ty) }
+  if e.kind == E_MEMBER {
+    if e.a.kind == E_ID {                        # `Enum.Variant` -> its ordinal, a compile-time int
+      let ord = enum_ordinal(e.a.s, e.s)
+      if ord >= 0 { return val(itoa(ord), "int") }
+    }
+    let a = emit_member_addr(e);  return emit_load_at(a, g_addr_ty)
+  }
   if e.kind == E_INDEX  { let a = emit_index_addr(e);   return emit_load_at(a, g_addr_ty) }
   if e.kind == E_CALL   { return emit_call(e) }
   if e.kind == E_BIN    { return emit_bin(e) }

selfhost/parse.ludic

@@ -296,6 +296,7 @@ fn parse_one_decl() -> void {
     return
   }
   if is_id("struct") { push(prog, parse_struct()); return }
+  if is_id("enum") { push(prog, parse_enum()); return }
   if is_id("component") { push(prog, parse_component()); return }
   if is_id("archetype") { push(prog, parse_archetype()); return }
   if is_id("system") { push(prog, parse_system()); return }

selfhost/parse_game.ludic

@@ -96,6 +96,17 @@ fn parse_spawn() -> Node {
   eat_op("}"); return n
 }
 
+# enum Name { A, B, C } — named int constants; a variant's value is its index.
+# Accessed as `Name.A` (a compile-time int), so it names magic-int value spaces
+# (state ids, menu selections, mode registers) without a runtime cost.
+fn parse_enum() -> Node {
+  pi = pi + 1; let n = node(N_ENUM); n.s = eat_id(); skipnl(); eat_op("{")
+  while true { skipnl(); if is_op("}") { break }
+    let v = node(E_ID); v.s = eat_id(); push(n.kids, v)
+    if is_op(",") { pi = pi + 1 };  skipnl() }
+  eat_op("}"); return n
+}
+
 # archetype Name { CompA, CompB } — a named entity kind (bundle of components)
 fn parse_archetype() -> Node {
   pi = pi + 1; let n = node(N_ARCH); n.s = eat_id(); skipnl(); eat_op("{")

tools/editors/emacs/ludic-mode.el

@@ -11,8 +11,8 @@
 ;;; Code:
 
 (defconst ludic--declaration-keywords
-  '("game" "module" "import" "component" "archetype" "ui" "scene" "layer"
-    "const" "var" "export" "fn" "pure" "extern" "system" "edge" "start" "on"))
+  '("game" "module" "import" "component" "struct" "archetype" "enum" "ui" "scene" "layer"
+    "const" "var" "fn" "extern" "system" "start" "on"))
 
 (defconst ludic--clause-keywords
   '("phase" "query" "reads" "writes" "needs" "uses"

tools/editors/jetbrains/src/main/kotlin/io/ludic/ide/LudicTokens.kt

@@ -41,8 +41,8 @@ object LudicTokens {
  */
 object LudicVocabulary {
     val DECL = setOf(
-        "game", "module", "import", "component", "struct", "archetype", "ui", "scene", "layer",
-        "const", "var", "export", "fn", "pure", "extern", "system", "edge", "start", "on"
+        "game", "module", "import", "component", "struct", "archetype", "enum", "ui", "scene", "layer",
+        "const", "var", "fn", "extern", "system", "start", "on"
     )
     val CLAUSE = setOf(
         "phase", "query", "reads", "writes", "needs", "uses",

tools/editors/shared/ludic.tmLanguage.json

@@ -174,8 +174,8 @@
         { "name": "keyword.control.ludic", "match": "\\b(if|else|when|while|for|in|match|machine|become|enter|return|spawn|despawn|where|break|continue|new)\\b" },
         { "name": "keyword.operator.logical.ludic", "match": "\\b(and|or|not)\\b" },
         { "name": "keyword.other.clause.ludic", "match": "\\b(phase|query|reads|writes|needs|uses|requires|ensures|invariant|effects|on)\\b" },
-        { "name": "keyword.other.ludic", "match": "\\b(import|export|pure|extern|start|edge)\\b" },
-        { "name": "storage.type.ludic", "match": "\\b(game|module|component|archetype|ui|scene|layer|const|var|let|fn|system|state)\\b" },
+        { "name": "keyword.other.ludic", "match": "\\b(import|extern|start)\\b" },
+        { "name": "storage.type.ludic", "match": "\\b(game|module|component|struct|archetype|enum|ui|scene|layer|const|var|let|fn|system|state)\\b" },
         { "name": "support.type.primitive.ludic", "match": "\\b(int|fixed|bool|entity|str|ptr|void)\\b" },
         { "name": "constant.language.boolean.ludic", "match": "\\b(true|false)\\b" },
         { "name": "constant.language.phase.ludic", "match": "\\b(Start|Input|FixedUpdate|Update|LateUpdate|Render)\\b" }

tools/editors/vscode/syntaxes/ludic.tmLanguage.json

@@ -174,8 +174,8 @@
         { "name": "keyword.control.ludic", "match": "\\b(if|else|when|while|for|in|match|machine|become|enter|return|spawn|despawn|where|break|continue|new)\\b" },
         { "name": "keyword.operator.logical.ludic", "match": "\\b(and|or|not)\\b" },
         { "name": "keyword.other.clause.ludic", "match": "\\b(phase|query|reads|writes|needs|uses|requires|ensures|invariant|effects|on)\\b" },
-        { "name": "keyword.other.ludic", "match": "\\b(import|export|pure|extern|start|edge)\\b" },
-        { "name": "storage.type.ludic", "match": "\\b(game|module|component|archetype|ui|scene|layer|const|var|let|fn|system|state)\\b" },
+        { "name": "keyword.other.ludic", "match": "\\b(import|extern|start)\\b" },
+        { "name": "storage.type.ludic", "match": "\\b(game|module|component|struct|archetype|enum|ui|scene|layer|const|var|let|fn|system|state)\\b" },
         { "name": "support.type.primitive.ludic", "match": "\\b(int|fixed|bool|entity|str|ptr|void)\\b" },
         { "name": "constant.language.boolean.ludic", "match": "\\b(true|false)\\b" },
         { "name": "constant.language.phase.ludic", "match": "\\b(Start|Input|FixedUpdate|Update|LateUpdate|Render)\\b" }

tools/ludic-tools/ludic_syntax.h

@@ -52,8 +52,8 @@ typedef struct {
  * mirror the compiler's parser: anything parse_decl() dispatches on is a
  * declaration keyword, anything stmt() dispatches on is a statement keyword. */
 static const char* LUDIC_KW_DECL[] = {
-    "game","module","import","component","struct","archetype","ui","scene","layer",
-    "const","var","export","fn","pure","extern","system","edge","start","on", 0
+    "game","module","import","component","struct","archetype","enum","ui","scene","layer",
+    "const","var","fn","extern","system","start","on", 0
 };
 static const char* LUDIC_KW_CLAUSE[] = {
     "phase","query","reads","writes","needs","uses",