lua: proper early-return via guard+raise sentinel; fixes if-then-return-end-rest +3 tests

lib/lua/runtime.sx

@@ -1503,9 +1503,15 @@
     (guard
       (e (true (list (quote lua-multi) nil (str e))))
       (let ((compiled (lua-transpile src)))
-        (let ((wrapped (list (make-symbol "fn") (list (make-symbol "&rest") (make-symbol "__args"))
+        (let ((guarded (list
-                             (list (make-symbol "let") (list) compiled))))
+                         (make-symbol "guard")
-          (eval-expr wrapped))))))
+                         (list (make-symbol "e")
+                           (list
+                             (list (make-symbol "lua-return-sentinel?") (make-symbol "e"))
+                             (list (make-symbol "lua-return-value") (make-symbol "e"))))
+                         (list (make-symbol "let") (list) compiled))))
+          (let ((wrapped (list (make-symbol "fn") (list (make-symbol "&rest") (make-symbol "__args")) guarded)))
+            (eval-expr wrapped)))))))
 
 (define loadstring lua-loadstring)
 (define load lua-loadstring)
@@ -1630,3 +1636,13 @@
         (va-build skip)
         (dict-set! t "n" n)
         t))))
+
+;; Return-sentinel: wrap function bodies so mid-block `return` can escape.
+(define
+  lua-return-sentinel?
+  (fn (e)
+    (and (= (type-of e) "list") (> (len e) 0) (= (first e) (quote lua-ret)))))
+
+(define
+  lua-return-value
+  (fn (e) (if (> (len e) 1) (nth e 1) nil)))

lib/lua/scoreboard.json

@@ -11,7 +11,7 @@
   "top_failure_modes": [
     [
       "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      9
+      10
     ],
     [
       "timeout",
@@ -22,11 +22,7 @@
       2
     ],
     [
-      "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: attempt to compare incompat",
+      "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: concat on list and string\\\\",
-      1
-    ],
-    [
-      "other: Unhandled exception: \\\"Not callable: nil (kont=10 frames)\\",
       1
     ]
   ],
@@ -47,19 +43,19 @@
       "name": "attrib.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 6000
+      "ms": 6225
     },
     {
       "name": "big.lua",
       "status": "timeout",
       "reason": "per-test timeout",
-      "ms": 8006
+      "ms": 8008
     },
     {
       "name": "calls.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 4946
+      "ms": 5175
     },
     {
       "name": "checktable.lua",
@@ -71,7 +67,7 @@
       "name": "closure.lua",
       "status": "timeout",
       "reason": "per-test timeout",
-      "ms": 8003
+      "ms": 8007
     },
     {
       "name": "code.lua",
@@ -82,8 +78,8 @@
     {
       "name": "constructs.lua",
       "status": "fail",
-      "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: attempt to compare incompat",
+      "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: concat on list and string\\\\",
-      "ms": 4533
+      "ms": 4874
     },
     {
       "name": "db.lua",
@@ -94,14 +90,14 @@
     {
       "name": "errors.lua",
       "status": "fail",
-      "reason": "other: Unhandled exception: \\\"Not callable: nil (kont=10 frames)\\",
+      "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 3217
+      "ms": 3289
     },
     {
       "name": "events.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 7215
+      "ms": 7546
     },
     {
       "name": "files.lua",
@@ -119,13 +115,13 @@
       "name": "literals.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 1901
+      "ms": 1888
     },
     {
       "name": "locals.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: attempt to call non-functio",
-      "ms": 1693
+      "ms": 1721
     },
     {
       "name": "main.lua",
@@ -137,43 +133,43 @@
       "name": "math.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 4095
+      "ms": 4231
     },
     {
       "name": "nextvar.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 7177
+      "ms": 7290
     },
     {
       "name": "pm.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 6048
+      "ms": 6155
     },
     {
       "name": "sort.lua",
       "status": "timeout",
       "reason": "per-test timeout",
-      "ms": 8007
+      "ms": 8006
     },
     {
       "name": "strings.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 3990
+      "ms": 4215
     },
     {
       "name": "vararg.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 2249
+      "ms": 2288
     },
     {
       "name": "verybig.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: attempt to call non-functio",
-      "ms": 572
+      "ms": 622
     }
   ]
 }

lib/lua/scoreboard.md

@@ -5,11 +5,10 @@ fail=13 timeout=3 skip=8 total=24
 
 ## Top failure modes
 
-- **9x** other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\
+- **10x** other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\
 - **3x** timeout
 - **2x** other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio
-- **1x** other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to compare incompat
+- **1x** other: Unhandled exception: \"Unhandled exception: \\\"lua: concat on list and string\\
-- **1x** other: Unhandled exception: \"Not callable: nil (kont=10 frames)\
 
 ## Per-test results
 
@@ -17,25 +16,25 @@ fail=13 timeout=3 skip=8 total=24
 |---|---|---|---:|
 | all.lua | skip | driver uses dofile to chain other tests | 0 |
 | api.lua | skip | requires testC (C debug library) | 0 |
-| attrib.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 6000 |
+| attrib.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 6225 |
-| big.lua | timeout | per-test timeout | 8006 |
+| big.lua | timeout | per-test timeout | 8008 |
-| calls.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 4946 |
+| calls.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 5175 |
 | checktable.lua | skip | internal debug helpers | 0 |
-| closure.lua | timeout | per-test timeout | 8003 |
+| closure.lua | timeout | per-test timeout | 8007 |
 | code.lua | skip | bytecode inspection via debug library | 0 |
-| constructs.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to compare incompat | 4533 |
+| constructs.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: concat on list and string\\ | 4874 |
 | db.lua | skip | debug library | 0 |
-| errors.lua | fail | other: Unhandled exception: \"Not callable: nil (kont=10 frames)\ | 3217 |
+| errors.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 3289 |
-| events.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 7215 |
+| events.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 7546 |
 | files.lua | skip | io library | 0 |
 | gc.lua | skip | collectgarbage / finalisers | 0 |
-| literals.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 1901 |
+| literals.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 1888 |
-| locals.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio | 1693 |
+| locals.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio | 1721 |
 | main.lua | skip | standalone interpreter driver | 0 |
-| math.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 4095 |
+| math.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 4231 |
-| nextvar.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 7177 |
+| nextvar.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 7290 |
-| pm.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 6048 |
+| pm.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 6155 |
-| sort.lua | timeout | per-test timeout | 8007 |
+| sort.lua | timeout | per-test timeout | 8006 |
-| strings.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 3990 |
+| strings.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 4215 |
-| vararg.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 2249 |
+| vararg.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 2288 |
-| verybig.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio | 572 |
+| verybig.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio | 622 |

lib/lua/test.sh

@@ -936,6 +936,14 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 1842)
 (eval "(lua-eval-ast \"if -2^2 == -4 then return 1 else return 0 end\")")
 
+;; ── Early-return inside nested block (guard+raise sentinel) ──
+(epoch 1850)
+(eval "(lua-eval-ast \"local function f(n) if n < 0 then return -1 end return n * 2 end return f(-5)\")")
+(epoch 1851)
+(eval "(lua-eval-ast \"local function f(n) if n < 0 then return -1 end return n * 2 end return f(7)\")")
+(epoch 1852)
+(eval "(lua-eval-ast \"function f(i) if type(i) ~= \\\"number\\\" then return i, \\\"jojo\\\" end if i > 0 then return i, f(i-1) end end local a, b = f(3) return a\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 60 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -1414,6 +1422,11 @@ check 1840 "-2^2 = -4"                      '-4'
 check 1841 "2^3^2 = 512 (right-assoc)"      '512'
 check 1842 "-2^2 == -4 true"                '1'
 
+# ── Early-return inside nested block ─────────────────────────
+check 1850 "early return negative path"     '-1'
+check 1851 "non-early return path"          '14'
+check 1852 "nested early-return recursion"  '3'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "ok $PASS/$TOTAL Lua-on-SX tests passed"

lib/lua/transpile.sx

@@ -187,6 +187,17 @@
       (make-symbol "arg")
       (list (make-symbol "lua-varargs-arg-table") (make-symbol "__args") n))))
 
+(define
+  lua-tx-function-guard
+  (fn (body-sx)
+    (list
+      (make-symbol "guard")
+      (list (make-symbol "e")
+        (list
+          (list (make-symbol "lua-return-sentinel?") (make-symbol "e"))
+          (list (make-symbol "lua-return-value") (make-symbol "e"))))
+      body-sx)))
+
 (define
   lua-tx-function
   (fn
@@ -200,7 +211,7 @@
           (list
             (make-symbol "fn")
             (list (make-symbol "&rest") (make-symbol "__args"))
-            (lua-tx body)))
+            (lua-tx-function-guard (lua-tx body))))
         (else
           (let
             ((bindings (lua-tx-function-bindings params 0)))
@@ -215,10 +226,11 @@
               (list
                 (make-symbol "fn")
                 (list (make-symbol "&rest") (make-symbol "__args"))
-                (list
+                (lua-tx-function-guard
-                  (make-symbol "let")
+                  (list
-                  all-bindings
+                    (make-symbol "let")
-                  (lua-tx body))))))))))
+                    all-bindings
+                    (lua-tx body)))))))))))
 
 (define
   lua-tx-block
@@ -460,13 +472,18 @@
     (node)
     (let
       ((exps (nth node 1)))
-      (cond
+      (let
-        ((= (len exps) 0) nil)
+        ((val
-        ((= (len exps) 1) (lua-tx (first exps)))
+          (cond
-        (else
+            ((= (len exps) 0) nil)
-          (list
+            ((= (len exps) 1) (lua-tx (first exps)))
-            (make-symbol "lua-pack-return")
+            (else
-            (cons (make-symbol "list") (lua-tx-multi-args exps 0))))))))
+              (list
+                (make-symbol "lua-pack-return")
+                (cons (make-symbol "list") (lua-tx-multi-args exps 0)))))))
+        (list
+          (make-symbol "raise")
+          (list (make-symbol "list") (list (make-symbol "quote") (make-symbol "lua-ret")) val))))))
 
 (define
   lua-tx-local-function
@@ -500,7 +517,9 @@
 
 (define
   lua-eval-ast
-  (fn (src) (let ((sx (lua-transpile src))) (eval-expr sx))))
+  (fn (src)
+    (let ((sx (lua-transpile src)))
+      (eval-expr (lua-tx-function-guard sx)))))
 
 (define
   lua-tx-multi-args

plans/lua-on-sx.md

@@ -82,6 +82,7 @@ Each item: implement → tests → tick box → update progress log.
 
 _Newest first. Agent appends on every commit._
 
+- 2026-04-24: lua: scoreboard iteration — **proper early-return via guard+raise sentinel**. Fixes long-logged limitation: `if cond then return X end ...rest` now exits the enclosing function; `rest` is skipped. `lua-tx-return` raises `(list 'lua-ret value)`; every function body and the top-level chunk + loadstring'd chunks wrap in a guard that catches the sentinel and returns its value. Eliminates "compare incompatible types" from constructs.lua (past line 40). 368/368 green (+3 early-return tests).
 - 2026-04-24: lua: scoreboard iteration — **unary-minus / `^` precedence fix**. Per Lua spec, `^` binds tighter than unary `-`, so `-2^2` should parse as `-(2^2) = -4`, not `(-2)^2 = 4`. My parser recursed into `parse-unary` and then let `^` bind to the already-negated operand. Added `parse-pow-chain` helper and changed the `else` branch of `parse-unary` to parse a primary + `^`-chain before returning; unary operators now wrap the full `^`-chain. Fixed `constructs.lua` past assert #3 (moved to compare-incompatible). 365/365 green (+3 precedence tests).
 - 2026-04-24: lua: scoreboard iteration — `lua-byte-to-char` regression fix. My previous change returned 2-char strings (`"\a"` etc.) for bytes that SX string literals can't express (0, 7, 8, 11, 12, 14–31, 127+), breaking `'a\0a'` length from 3 → 4. Now only 9/10/13 and printable 32-126 produce real bytes; others use a single `"?"` placeholder so `string.len` stays correct. literals.lua back to failing at assert #4 (was regressed to #2).
 - 2026-04-24: lua: scoreboard iteration — **decimal string escapes** `\ddd` (1-3 digits). Tokenizer `read-string` previously fell through to literal for digits, so `"\65"` came out as `"65"` not `"A"`. Added `read-decimal-escape!` consuming up to 3 digits while keeping value ≤255, plus `\a`/`\b`/`\f`/`\v` control escapes and `lua-byte-to-char` ASCII lookup. 362 tests (+2 escape tests).
@@ -133,4 +134,4 @@ _Shared-file issues that need someone else to fix. Minimal repro only._
 - **`string.find`/`match`/`gmatch`/`gsub` patterns are LITERAL only** — no `%d`/`%a`/`.`/`*`/`+`/etc. Implementing Lua patterns is a separate work item; literal search covers the common case.
 - **`string.format`** supports only `%s`, `%d`, `%f`, `%%`. No width/precision flags (`%.2f`, `%5d`).
 - **`string.char`** supports printable ASCII 32–126 plus `\t`/`\n`/`\r`; other codes error.
-- **Early `return` inside nested block** — `if cond then return nil end ...rest` doesn't exit the enclosing function; `rest` runs anyway. Use `if cond then return X else return Y end` instead. Likely needs guard+raise sentinel for proper fix.
+- ~~Early `return` inside nested block~~ — **FIXED 2026-04-24** via guard+raise sentinel (`lua-ret`). All function bodies and the top-level chunk wrap in a guard that catches the return-sentinel; `return` statements raise it.