static float rclamp(float a, float b, float x) {
  ret x < a ? a : x > b ? b : x;
}

static double rclamp(double a, double b, double x) {
  ret x < a ? a : x > b ? b : x;
}

static int rclamp(int a, int b, int x) {
  ret x < a ? a : x > b ? b : x;
}

static long rclamp(long a, long b, long x) {
  ret x < a ? a : x > b ? b : x;
}

Began life as a copy of #1018737