Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.5)
// Compass (v1.0.0.alpha.18)
// ----

@function str-explode($string, $delimiter, $separator: auto, $trim: false) {
  $_result: ();
  $_length: str-length($delimiter);

  // search for a substring occurence
  $_index:  str-index($string, $delimiter);
  @while $_index {
    // append string before the index
    @if $_index > 1 {
      $_result: append($_result, str-slice($string, 1, $_index - 1), $separator);
    }
    // append empty string
    @elseif not $trim {
      $_result: append($_result, '', $separator);
    }
    // slice string after the found substring
    $string: str-slice($string, $_index + $_length);
    // search for a new substring occurence
    $_index:  str-index($string, $delimiter);
  }
  // append remaining string
  @if str-length($string) != 0 or not $trim {
    $_result: append($_result, $string, $separator);
  }
  @return $_result;
}

@function str-to-number($string) {
  $_number-chars: '0' '1' '2' '3' '4' '5' '6' '7' '8' '9';
  $string: str-explode($string, '.');
  $_number: 0;

  // More than one decimal separator;
  @if length($string) > 2 {
    @return null;
  }

  // Integer part string
  $_part:   nth($string, 1);
  $_length: str-length($_part);
  @if $_length > 0 {
    $_coef: 1;
    @for $_i from $_length through 1 {
      $_n: index($_number-chars, str-slice($_part, $_i, $_i));
      // char is not a number
      @if not $_n {
        @return null;
      }
      $_number: $_number + ($_n - 1) * $_coef;
      $_coef: $_coef * 10;
    }
  }

  // Decimal part string
  @if length($string) == 2 {
    $_part:   nth($string, 2);
    $_length: str-length($_part);
    @if $_length > 0 {
      $_coef: 10;
      @for $_i from 1 through $_length {
        $_n: index($_number-chars, str-slice($_part, $_i, $_i));
        // char is not a number
        @if not $_n {
          @return null;
        }
        $_number: $_number + ($_n - 1) / $_coef;
        $_coef: $_coef * 10;
      }
    }
  }
  
  @return $_number;
}

test1 {
  type:  type-of(str-to-number('0.11'));
  value: str-to-number('0.11');
  weird: str-to-number('0.11') == 0.11;
}

test2 {
  type:  type-of(str-to-number('0.12'));
  value: str-to-number('0.12');
  weird: str-to-number('0.12') == 0.12;
}

test3 {
  type:  type-of(str-to-number('0.13'));
  value: str-to-number('0.13');
  weird: str-to-number('0.13') == 0.13;
}

SassMeister-output.css

test1 {
  type: number;
  value: 0.11;
  weird: true;
}

test2 {
  type: number;
  value: 0.12;
  weird: false;
}

test3 {
  type: number;
  value: 0.13;
  weird: true;
}