_function.scss

// What's the precision of $number
@function precision($number) {
    @if is-float($number) {
        $number: #{strip-units($number)};
        @if str-index($number, ".") != null {
            @return str-length($number) - str-index($number, ".");
        }
    }

    @return 0;
}

// Is a $number a float?
// Inspired by https://github.com/Team-Sass/Sassy-math/blob/master/sass/math.scss#L297
@function is-float($number) {
    @if type-of($number) != "number" {
        @warn "#{$number} is not a number!";
        @return false;
    }

    @return $number - floor($number) != 0;
}

// Remove the unit from a $number
// Inspired by https://github.com/nex3/sass/issues/533#issuecomment-11675408
@function strip-units($number) {
    @return $number / ($number * 0 + 1);
}

// Number exponents
// Inspired by https://github.com/Team-Sass/Sassy-math/blob/master/sass/math.scss#L36
@function exponent($base, $exponent) {
    $value: $base;

    // positive intergers get multiplied
    @if $exponent > 1 {
        @for $i from 2 through $exponent {
            $value: $value * $base;
        }
    }

    // negitive intergers get divided. A number divided by itself is 1
    @if $exponent < 1 {
        @for $i from 0 through -$exponent {
            $value: $value / $base;
        }
    }

    @return $value;
}

// Increment a number by it's smallest precision, preserving units
@function increment($number) {
    @return $number + 1 / exponent(10, precision($number));
}

// Detect if we're running with compass
@function is-compass() {
    @return function-exists("compass-extensions") and type-of(nonexistent()) == string;
}