✨ update std/math

std/math.nas

@@ -62,6 +62,8 @@ var ln = func(x) {
 }
 
 var _iln10 = 1/ln(10);
+
+# log10 is alias of lg
 var log10 = lg;
 
 var sqrt = func(x) {
@@ -96,6 +98,14 @@ var min = func(x, arg...) {
     return res;
 }
 
+var avg = func(arg...) {
+    var x = 0;
+    foreach(var i;arg) {
+        x += i;
+    }
+    return x/size(arg);
+}
+
 var mod = func(n, m) {
     var x = n-int(n/m)*m;
     return x<0? x+abs(m):x;