Memoization Example

memoization.scss

// ----
// Sass (v3.3.4)
// Compass (v1.0.0.alpha.18)
// ----

//// Fibonacci Function
@function fibonacci($n) {
 $fib: 0 1;
 @for $i from 1 through nth($n,1) {
   $new: nth($fib, length($fib)) + nth($fib, length($fib) - 1);
   $fib: append($fib, $new);
 }
 @return $fib;
}


//// Create $memo map
$memo: ();

//// memo-update
@function memo-update($function, $params, $value) {
 $result:();
 @if map-has-key($memo, $function) {
   $sub-map-new: map-merge(map-get($memo,$function),($params: $value));
   $result: map-merge($memo, ($function: ($sub-map-new) ));
 }
 @else {
   $result: map-merge($memo, ($function: ($params: $value)));
 }
 
 @return $result;
}

//// memo-get
@function memo-get($function, $params) {
  $result: map-get(map-get($memo,$function),$params);
  @return $result;
}

//// call-function
@function call-function($function, $params...) {
  @if map-has-key($memo, $function) {
      $result: memo-get($function, $params);
      @if $result != null {
          @return $result;
      }
  }
  $result: call($function, $params...);
  $memo: memo-update($function, $params, $result) !global;
  @return $result;
}

////
// Comment out function calls and uncomment memoization calls
// View difference in time to compile
////

//// Traditional function calls ~1.5s
$fib1: fibonacci(1000);
$fib2: fibonacci(1000);
$fib3: fibonacci(1000);

//// Function calls made with memoization ~.5s
// $fib1: call-function(fibonacci, 1000);
// $fib2: call-function(fibonacci, 1000);
// $fib3: call-function(fibonacci, 1000);


div {
  foo: inspect($fib1);
  bar: inspect($memo);
}