@function getUnit($value) {
  @return str-slice($value * 0 + "", 2, -1);
}

@function is-number($value) {
  @return type-of($value)=="number";
}

@function is-time($value) {
  @return is-number($value) and index("ms""s", unit($value)) !=null;
}

@function is-duration($value) {
  @return is-time($value);
}

@function is-angle($value) {
  @return is-number($value) and index("deg""rad""grad""turn", unit($value)) !=null;
}

@function is-frequency($value) {
  @return is-number($value) and index("Hz""kHz", unit($value)) !=null;
}

@function is-integer($value) {
  @return is-number($value) and round($value)==$value;
}

@function is-relative-length($value) {
  @return is-number($value) and index("em""ex""ch""rem""vw""vh""vmin""vmax", unit($value)) !=null;
}

@function is-absolute-length($value) {
  @return is-number($value) and index("cm""mm""in""px""pt""pc", unit($value)) !=null;
}

@function is-percentage($value) {
  @return is-number($value) and unit($value)=="%";
}

@function is-length($value) {
  @return is-relative-length($value) or is-absolute-length($value);
}

@function is-resolution($value) {
  @return is-number($value) and index("dpi""dpcm""dppx", unit($value)) !=null;
}

@function is-position($value) {
  @return is-length($value) or is-percentage($value) or index("top""right""bottom""left""center", $value) !=null;
}

@function elevation($value) {
  @return $value / 10deg;
}