///
/// Checks whether `$functions` exist in global scope.
///
/// @access private
///
/// @param {ArgList} $functions - list of functions to check for
///
/// @return {Bool} Whether or not there are missing dependencies
///
 
@function sl-missing-dependencies($functions...) {
  $missing-dependencies: ();
  
  @each $function in $functions {
    @if not function-exists($function) {
      $missing-dependencies: append($missing-dependencies, $function, comma);
    }
  }
  
  @if length($missing-dependencies) > 0 {
    @error 'Unmet dependencies! The following functions are required: #{$missing-dependencies}.';
  }

  @return length($missing-dependencies) > 0;
}