/// Cast a value to a number if possible or return 0
/// @param {String} $value - complete source
/// @return {Number}
@function _sc-to-number($value) {
  // In case everything's good
  @if type-of($value) == "number" {
    @return $value;
  }

  // Boolean to number
  @if $value == true  {
    @return 1;
  }

  // Fail
  @if type-of($value) != "string" {
    @return 0;
  }

  // Trying to cast
  $pointer: 1;
  $result: 0;
  $allowed: "-" "0" "1" "2" "3" "4" "5" "6" "7" "8" "9"; // Allowed characted to start with
  $first: str-slice($value, $pointer, $pointer); // First character of the number
  $minus: $first == "-"; // Is it negative?

  // Early check for errors
  @if not index($allowed, $first) {
    @warn "Could not cast `#{inspect($value)} into number.";
    @return 0;
  }

  // Find the integer part
  $find-integer: _sc-find-integer($value, $pointer);
  $pointer: nth($find-integer, 1);
  $result:  nth($find-integer, 2);

  // Find digits
  @if str-slice($value, $pointer, $pointer) == "." {
    $find-digits: _sc-find-digits($value, $pointer);
    $pointer: nth($find-digits, 1);
    $digits:  nth($find-digits, 2);
    $result: $result + $digits;
  }

  // In case of negative
  @if $minus {
    $result: $result * -1;
  }

  // In case of possible CSS unit
  @if $pointer < str-length($value) {
    $result: _sc-length($result, str-slice($value, $pointer));
  }

  @return $result;
}