lua: scoreboard iteration — rawget/rawset/raweq/rawlen + loadstring/load + select/assert + _G/_VERSION

lib/lua/runtime.sx

@@ -1340,3 +1340,104 @@
       (else (error (str "lua: module '" name "' not found"))))))
 
 (define require lua-require)
+
+;; ── raw operations + loadstring ───────────────────────────────
+(define
+  lua-rawget
+  (fn (t k)
+    (cond
+      ((not (= (type-of t) "dict")) nil)
+      ((has-key? t (str k)) (get t (str k)))
+      (else nil))))
+
+(define
+  lua-rawset
+  (fn (t k v)
+    (begin (dict-set! t (str k) v) t)))
+
+(define
+  lua-rawequal
+  (fn (a b)
+    (cond
+      ((and (= a nil) (= b nil)) true)
+      ((or (= a nil) (= b nil)) false)
+      ((and (= (type-of a) (type-of b)) (= a b)) true)
+      (else false))))
+
+(define
+  lua-rawlen
+  (fn (v)
+    (cond
+      ((= (type-of v) "string") (len v))
+      ((= (type-of v) "dict")
+        (let ((n 0))
+          (begin
+            (define
+              rl-count
+              (fn (i)
+                (if (has-key? v (str i))
+                    (begin (set! n i) (rl-count (+ i 1)))
+                    n)))
+            (rl-count 1)
+            n)))
+      (else 0))))
+
+(define rawget lua-rawget)
+(define rawset lua-rawset)
+(define rawequal lua-rawequal)
+(define rawlen lua-rawlen)
+
+;; loadstring(src) returns a function that, when called, evaluates src.
+(define
+  lua-loadstring
+  (fn (src)
+    (fn (&rest args) (lua-eval-ast src))))
+
+(define loadstring lua-loadstring)
+(define load lua-loadstring)
+
+;; select(n, ...) — Lua 5.1 built-in. select("#", ...) is arg count; select(i, ...) returns args from i on.
+(define
+  lua-select
+  (fn (&rest args)
+    (let ((n (first args)) (rest-args (rest args)))
+      (cond
+        ((= n "#") (len rest-args))
+        ((= (type-of n) "number")
+          (let ((i (- n 1)))
+            (cond
+              ((< i 0) (error "lua: bad argument to select"))
+              ((>= i (len rest-args)) nil)
+              (else
+                (let ((out (list (quote lua-multi))))
+                  (begin
+                    (define
+                      sel-loop
+                      (fn (j)
+                        (when (< j (len rest-args))
+                          (begin
+                            (set! out (append out (list (nth rest-args j))))
+                            (sel-loop (+ j 1))))))
+                    (sel-loop i)
+                    out))))))
+        (else (error "lua: bad argument to select"))))))
+
+(define select lua-select)
+
+;; assert(v, msg) — errors with msg if v is falsy.
+(define
+  lua-assert
+  (fn (&rest args)
+    (let ((v (first args)))
+      (cond
+        ((lua-truthy? v)
+          (cond
+            ((= (len args) 1) v)
+            (else (cons (quote lua-multi) args))))
+        (else
+          (error (if (> (len args) 1) (nth args 1) "assertion failed!")))))))
+
+(define assert lua-assert)
+
+(define _G {})
+(define _VERSION "Lua 5.1")