Use destructuring assignments for named parameters (#180)

test/codegen/expect/collection/algorithms.js

 dart_library.library('collection/algorithms', null, /* Imports */[
   "dart/_runtime",
   'dart/core',
   'dart/math'
 ], /* Lazy imports */[
 ], function(exports, dart, core, math) {
   'use strict';
   let dartx = dart.dartx;
   function _comparableBinarySearch(list, key) {
     let min = 0;
     let max = list[dartx.length];
     while (dart.notNull(min) < dart.notNull(max)) {
       let mid = dart.notNull(min) + (dart.notNull(max) - dart.notNull(min) >> 1);
       let element = list[dartx.get](mid);
       let comp = element[dartx.compareTo](key);
       if (comp == 0)
         return mid;
       if (dart.notNull(comp) < 0) {
         min = dart.notNull(mid) + 1;
       } else {
         max = mid;
       }
     }
     return -1;
   }
   dart.fn(_comparableBinarySearch, core.int, [core.List$(core.Comparable), core.Comparable]);
-  function binarySearch(sortedList, key, opts) {
-    let compare = opts && 'compare' in opts ? opts.compare : null;
+  function binarySearch(sortedList, key, {compare = null} = {}) {
     if (compare == null) {
       return _comparableBinarySearch(dart.as(sortedList, core.List$(core.Comparable)), dart.as(key, core.Comparable));
     }
     let min = 0;
     let max = sortedList[dartx.length];
     while (dart.notNull(min) < dart.notNull(max)) {
       let mid = dart.notNull(min) + (dart.notNull(max) - dart.notNull(min) >> 1);
       let element = sortedList[dartx.get](mid);
       let comp = dart.dcall(compare, element, key);
       if (comp == 0)
@@ skipping 36 matching lines @@
   }
   dart.fn(reverse, dart.void, [core.List], [core.int, core.int]);
   function _reverse(list, start, end) {
     for (let i = start, j = dart.notNull(end) - 1; dart.notNull(i) < dart.notNull(j); i = dart.notNull(i) + 1, j = dart.notNull(j) - 1) {
       let tmp = list[dartx.get](i);
       list[dartx.set](i, list[dartx.get](j));
       list[dartx.set](j, tmp);
     }
   }
   dart.fn(_reverse, dart.void, [core.List, core.int, core.int]);
-  function insertionSort(list, opts) {
-    let compare = opts && 'compare' in opts ? opts.compare : null;
-    let start = opts && 'start' in opts ? opts.start : 0;
-    let end = opts && 'end' in opts ? opts.end : null;
+  function insertionSort(list, {compare = null, start = 0, end = null} = {}) {
     if (end == null)
       end = list[dartx.length];
     if (compare == null)
       compare = core.Comparable.compare;
     _insertionSort(list, compare, start, end, dart.notNull(start) + 1);
   }
   dart.fn(insertionSort, dart.void, [core.List], {compare: dart.functionType(core.int, [dart.dynamic, dart.dynamic]), start: core.int, end: core.int});
   function _insertionSort(list, compare, start, end, sortedUntil) {
     for (let pos = sortedUntil; dart.notNull(pos) < dart.notNull(end); pos = dart.notNull(pos) + 1) {
       let min = start;
       let max = pos;
       let element = list[dartx.get](pos);
       while (dart.notNull(min) < dart.notNull(max)) {
         let mid = dart.notNull(min) + (dart.notNull(max) - dart.notNull(min) >> 1);
         let comparison = dart.dcall(compare, element, list[dartx.get](mid));
         if (dart.notNull(comparison) < 0) {
           max = mid;
         } else {
           min = dart.notNull(mid) + 1;
         }
       }
       list[dartx.setRange](dart.notNull(min) + 1, dart.notNull(pos) + 1, list, min);
       list[dartx.set](min, element);
     }
   }
   dart.fn(_insertionSort, dart.void, [core.List, dart.functionType(core.int, [dart.dynamic, dart.dynamic]), core.int, core.int, core.int]);
   let _MERGE_SORT_LIMIT = 32;
-  function mergeSort(list, opts) {
-    let start = opts && 'start' in opts ? opts.start : 0;
-    let end = opts && 'end' in opts ? opts.end : null;
-    let compare = opts && 'compare' in opts ? opts.compare : null;
+  function mergeSort(list, {start = 0, end = null, compare = null} = {}) {
     if (end == null)
       end = list[dartx.length];
     if (compare == null)
       compare = core.Comparable.compare;
     let length = dart.notNull(end) - dart.notNull(start);
     if (dart.notNull(length) < 2)
       return;
     if (dart.notNull(length) < dart.notNull(_MERGE_SORT_LIMIT)) {
       _insertionSort(list, compare, start, end, dart.notNull(start) + 1);
       return;
@@ skipping 105 matching lines @@
     target[dartx.setRange](targetOffset, dart.notNull(targetOffset) + (dart.notNull(secondEnd) - dart.notNull(cursor2)), secondList, cursor2);
   }
   dart.fn(_merge, dart.void, [dart.functionType(core.int, [dart.dynamic, dart.dynamic]), core.List, core.int, core.int, core.List, core.int, core.int, core.List, core.int]);
   // Exports:
   exports.binarySearch = binarySearch;
   exports.shuffle = shuffle;
   exports.reverse = reverse;
   exports.insertionSort = insertionSort;
   exports.mergeSort = mergeSort;
 });