lua: math.mod (alias) + math.frexp + math.ldexp

lib/lua/runtime.sx

@@ -1425,6 +1425,35 @@
 (dict-set! math "min" lua-math-min)
 (dict-set! math "max" lua-math-max)
 (dict-set! math "fmod" lua-math-fmod)
+(dict-set! math "mod" lua-math-fmod)
+(define
+  lua-math-frexp
+  (fn (x)
+    (cond
+      ((= x 0) (list (quote lua-multi) 0 0))
+      (else
+        (let ((sign (if (< x 0) -1 1)) (ax (abs x)) (e 0))
+          (begin
+            (define
+              fr-up
+              (fn ()
+                (when (>= ax 1)
+                  (begin (set! ax (/ ax 2)) (set! e (+ e 1)) (fr-up)))))
+            (define
+              fr-dn
+              (fn ()
+                (when (< ax 0.5)
+                  (begin (set! ax (* ax 2)) (set! e (- e 1)) (fr-dn)))))
+            (fr-up)
+            (fr-dn)
+            (list (quote lua-multi) (* sign ax) e)))))))
+
+(define
+  lua-math-ldexp
+  (fn (m e) (* m (pow 2 e))))
+
+(dict-set! math "frexp" lua-math-frexp)
+(dict-set! math "ldexp" lua-math-ldexp)
 (dict-set! math "modf" lua-math-modf)
 (dict-set! math "random" lua-math-random)
 (dict-set! math "randomseed" lua-math-randomseed)