Add ^, gcd and lcm to math

lib/pure/math.nim

@@ -329,6 +329,30 @@ proc standardDeviation*(s: RunningStat): float =
 {.pop.}
 {.pop.}
 
+proc `^`*[T](x, y: T): T =
+  ## Computes ``x`` to the power ``y`. ``x`` must be non-negative, use
+  ## `pow <#pow,float,float>` for negative exponents.
+  assert y >= 0
+  var (x, y) = (x, y)
+  result = 1
+
+  while y != 0:
+    if (y and 1) != 0:
+      result *= x
+    y = y shr 1
+    x *= x
+
+proc gcd*[T](x, y: T): T =
+  ## Computes the greatest common divisor of ``x`` and ``y``.
+  if y != 0:
+    gcd(y, x mod y)
+  else:
+    x.abs
+
+proc lcm*[T](x, y: T): T =
+  ## Computes the least common multiple of ``x`` and ``y``.
+  x div gcd(x, y) * y
+
 when isMainModule and not defined(JS):
   proc gettime(dummy: ptr cint): cint {.importc: "time", header: "<time.h>".}