lua-runtime: add math/string/table stdlib + delay/force (185/185 pass)

math: abs/ceil/floor/sqrt/sin/cos/tan/asin/acos/atan/exp/log/max/min/pi/huge
string: len/sub/upper/lower/rep/reverse/byte/char/find/match/gmatch/gsub
table: insert/remove/concat/sort
lua-force: force promises (delay thunk protocol)
Fix lua-len: replace has? (unavailable in sx_server) with nil-check.
Fix string.byte: use string->list to get char type, not nth on string.
Fix string.char: truncate float codes before integer->char.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/lua/runtime.sx

@@ -123,7 +123,7 @@
               (fn
                 (i)
                 (if
-                  (has? a (str i))
+                  (not (= (get a (str i)) nil))
                   (begin (set! n i) (count-loop (+ i 1)))
                   n)))
             (count-loop 1))))
@@ -152,7 +152,9 @@
                   (cond
                     ((= (first f) "pos")
                       (begin
-                        (set! t (assoc t (str array-idx) (nth f 1)))
+                        (set!
+                          t
+                          (assoc t (str array-idx) (nth f 1)))
                         (set! array-idx (+ array-idx 1))))
                     ((= (first f) "kv")
                       (let
@@ -169,3 +171,108 @@
     (if (= t nil) nil (let ((v (get t (str k)))) (if (= v nil) nil v)))))
 
 (define lua-set! (fn (t k v) (assoc t (str k) v)))
+
+;; ---------------------------------------------------------------------------
+;; Helpers for stdlib
+;; ---------------------------------------------------------------------------
+
+;; Apply a char function to every character in a string
+(define (lua-str-map s fn) (list->string (map fn (string->list s))))
+
+;; Repeat string s n times
+(define
+  (lua-str-rep s n)
+  (letrec
+    ((go (fn (acc i) (if (= i 0) acc (go (str acc s) (- i 1))))))
+    (go "" n)))
+
+;; Force a promise created by delay
+(define
+  (lua-force p)
+  (if
+    (and (dict? p) (get p :_promise))
+    (if (get p :forced) (get p :value) ((get p :thunk)))
+    p))
+
+;; ---------------------------------------------------------------------------
+;; math — Lua math library
+;; ---------------------------------------------------------------------------
+
+(define math {:asin asin :floor floor :exp exp :huge 1e+308 :tan tan :sqrt sqrt :log log :abs abs :ceil ceil :sin sin :max (fn (a b) (if (> a b) a b)) :acos acos :min (fn (a b) (if (< a b) a b)) :cos cos :pi 3.14159 :atan atan})
+
+;; ---------------------------------------------------------------------------
+;; string — Lua string library
+;; ---------------------------------------------------------------------------
+
+(define
+  (lua-string-find s pat)
+  (let
+    ((m (regexp-match (make-regexp pat) s)))
+    (if (= m nil) nil (list (+ (get m :start) 1) (get m :end)))))
+
+(define
+  (lua-string-match s pat)
+  (let
+    ((m (regexp-match (make-regexp pat) s)))
+    (if
+      (= m nil)
+      nil
+      (let
+        ((groups (get m :groups)))
+        (if (= (len groups) 0) (get m :match) (first groups))))))
+
+(define
+  (lua-string-gmatch s pat)
+  (map (fn (m) (get m :match)) (regexp-match-all (make-regexp pat) s)))
+
+(define
+  (lua-string-gsub s pat repl)
+  (regexp-replace-all (make-regexp pat) s repl))
+
+(define string {:rep lua-str-rep :sub (fn (s i &rest j-args) (let ((slen (len s)) (j (if (= (len j-args) 0) -1 (first j-args)))) (let ((from (if (< i 0) (let ((r (+ slen i))) (if (< r 0) 0 r)) (- i 1))) (to (if (< j 0) (let ((r (+ slen j 1))) (if (< r 0) 0 r)) (if (> j slen) slen j)))) (if (> from to) "" (substring s from to))))) :len (fn (s) (len s)) :upper (fn (s) (lua-str-map s char-upcase)) :char (fn (&rest codes) (list->string (map (fn (c) (integer->char (truncate c))) codes))) :gmatch lua-string-gmatch :gsub lua-string-gsub :lower (fn (s) (lua-str-map s char-downcase)) :byte (fn (s &rest args) (char->integer (nth (string->list s) (- (if (= (len args) 0) 1 (first args)) 1)))) :match lua-string-match :find lua-string-find :reverse (fn (s) (list->string (reverse (string->list s))))})
+
+;; ---------------------------------------------------------------------------
+;; table — Lua table library
+;; ---------------------------------------------------------------------------
+
+(define
+  (lua-table-insert t v)
+  (assoc t (str (+ (lua-len t) 1)) v))
+
+(define
+  (lua-table-remove t &rest args)
+  (let
+    ((n (lua-len t))
+      (pos (if (= (len args) 0) (lua-len t) (first args))))
+    (letrec
+      ((slide (fn (t i) (if (< i n) (assoc (slide t (+ i 1)) (str i) (lua-get t (+ i 1))) (assoc t (str n) nil)))))
+      (slide t pos))))
+
+(define
+  (lua-table-concat t &rest args)
+  (let
+    ((sep (if (= (len args) 0) "" (first args)))
+      (n (lua-len t)))
+    (letrec
+      ((go (fn (acc i) (if (> i n) acc (go (str acc (if (= i 1) "" sep) (lua-to-string (lua-get t i))) (+ i 1))))))
+      (go "" 1))))
+
+(define
+  (lua-table-sort t)
+  (let
+    ((n (lua-len t)))
+    (letrec
+      ((collect (fn (i acc) (if (< i 1) acc (collect (- i 1) (cons (lua-get t i) acc)))))
+        (rebuild
+          (fn
+            (t i items)
+            (if
+              (= (len items) 0)
+              t
+              (rebuild
+                (assoc t (str i) (first items))
+                (+ i 1)
+                (rest items))))))
+      (rebuild t 1 (sort (collect n (list)))))))
+
+(define table {:sort lua-table-sort :concat lua-table-concat :insert lua-table-insert :remove lua-table-remove})