functions.scss

$my-color-names: ( 'inchworm', 'sunglow', 'scarlet');
$my-colors:      ( #a5de37,    #ffd426,   #ff4351 );

@each $name in $my-color-names {
  $index: index($my-color-names, $name);
  $color: nth($my-colors, $index);
  %my-#{$name}-background-color { background-color: $color; }
  %my-#{$name}-border-color     { border-color: $color; }
}

@function sub($string, $replace, $value) {
  $replace-len: str-length($replace);
  $replace-start: str-index($string, $replace);
  $string-len: str-length($string);
  $string-left: str-slice($string, 1, $replace-start - 1);
  $string-right: str-slice($string, $replace-start + $replace-len);
  @return #{$string-left}#{$value}#{$string-right};
}

@function parse-template($template, $value) {
  @return sub($template, 'VALUE', $value);
}