Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.4)
// Compass (v1.0.1)
// ----

@function char-from-code($iso-char) {
  $escapeworkaround: "\"\\#{$iso-char}\"";
  @return unquote($escapeworkaround);
}

.test {
  content: char-from-code(83);
}

@mixin icon ($name, $code) {
  $withslash: "\"\\#{$code}\"";
  .#{$name}:before {
    content: unquote($withslash);
  }
}
@include icon('test', '4556');

SassMeister-output.css

.test {
  content: "\83";
}

.test:before {
  content: "\4556";
}