Add all lists functions used in List module

bryanjos · bryanjos · commit ed4dbcc67894 · 2017-06-27T21:29:24.000-05:00
diff --git a/src/javascript/lib/core/erlang_compat/lists.js b/src/javascript/lib/core/erlang_compat/lists.js
@@ -1,4 +1,5 @@
 // http://erlang.org/doc/man/lists.html
+import ErlangTypes from 'erlang-types';
 
 function reverse(list) {
   return [...list].reverse();
@@ -10,7 +11,151 @@ function foreach(fun, list) {
   return Symbol.for('ok');
 }
 
+function duplicate(n, elem) {
+  const list = [];
+
+  while (list.length < n) {
+    list.push(elem);
+  }
+
+  return list;
+}
+
+function flatten(deepList, tail = []) {
+  const val = deepList.reduce((acc, value) => {
+    if (Array.isArray(value)) {
+      return acc.concat(flatten(value));
+    }
+
+    return acc.concat(value);
+  }, []);
+
+  return val.concat(tail);
+}
+
+function foldl(fun, acc0, list) {
+  return list.reduce((acc, value) => {
+    return fun(value, acc);
+  }, acc0);
+}
+
+function foldr(fun, acc0, list) {
+  return foldl(fun, acc0, reverse(list));
+}
+
+function keyfind(key, n, tupleList) {
+  for (const tuple of tupleList) {
+    if (tuple.get(n) === key) {
+      return tuple;
+    }
+  }
+
+  return false;
+}
+
+function keymember(key, n, tupleList) {
+  if (keyfind(key, n, tupleList) === false) {
+    return false;
+  }
+
+  return true;
+}
+
+function keyreplace(key, n, tupleList, newTuple) {
+  const newTupleList = [...tupleList];
+
+  for (let index = 0; index < newTupleList.length; index++) {
+    if (newTupleList[index].get(n) === key) {
+      newTupleList[index] = newTuple;
+      return newTupleList;
+    }
+  }
+
+  return newTupleList;
+}
+
+function keysort(n, tupleList) {
+  const newTupleList = [...tupleList];
+
+  return newTupleList.sort((a, b) => {
+    if (a.get(n) < b.get(n)) {
+      return -1;
+    } else if (a.get(n) > b.get(n)) {
+      return 1;
+    }
+
+    return 0;
+  });
+}
+
+function keystore(key, n, tupleList, newTuple) {
+  const newTupleList = [...tupleList];
+
+  for (let index = 0; index < newTupleList.length; index++) {
+    if (newTupleList[index].get(n) === key) {
+      newTupleList[index] = newTuple;
+      return newTupleList;
+    }
+  }
+
+  return newTupleList.concat(newTuple);
+}
+
+function keydelete(key, n, tupleList) {
+  const newTupleList = [];
+  let deleted = false;
+
+  for (let index = 0; index < tupleList.length; index++) {
+    if (deleted === false && tupleList[index].get(n) === key) {
+      deleted = true;
+    } else {
+      newTupleList.push(tupleList[index]);
+    }
+  }
+
+  return newTupleList;
+}
+
+function keytake(key, n, tupleList) {
+  const result = keyfind(key, n, tupleList);
+
+  if (result !== false) {
+    return new ErlangTypes.Tuple(
+      result.get(n),
+      result,
+      keydelete(key, n, tupleList)
+    );
+  }
+
+  return false;
+}
+
+function mapfoldl(fun, acc0, list1) {
+  const listResult = [];
+  let accResult = acc0;
+
+  for (const item of list1) {
+    const tuple = fun(item, accResult);
+    listResult.push(tuple.get(0));
+    accResult = tuple.get(1);
+  }
+
+  return new ErlangTypes.Tuple(listResult, accResult);
+}
+
 export default {
   reverse,
   foreach,
+  duplicate,
+  flatten,
+  foldl,
+  foldr,
+  keydelete,
+  keyfind,
+  keymember,
+  keyreplace,
+  keysort,
+  keystore,
+  keytake,
+  mapfoldl,
 };
diff --git a/src/javascript/tests/core/erlang_compat/lists_spec.js b/src/javascript/tests/core/erlang_compat/lists_spec.js
@@ -4,3 +4,25 @@ import Core from '../../../lib/core';
 test('reverse', t => {
   t.deepEqual(Core.lists.reverse([1, 2, 3]), [3, 2, 1]);
 });
+
+test('duplicate', t => {
+  t.deepEqual(Core.lists.duplicate(0, 1), []);
+  t.deepEqual(Core.lists.duplicate(1, 1), [1]);
+  t.deepEqual(Core.lists.duplicate(2, 1), [1, 1]);
+});
+
+test('flatten', t => {
+  t.deepEqual(Core.lists.flatten([1, 2, 3]), [1, 2, 3]);
+  t.deepEqual(Core.lists.flatten([1, [[2], 3]]), [1, 2, 3]);
+});
+
+test('foldl', t => {
+  t.deepEqual(Core.lists.foldl((v, acc) => acc + v, 0, [1, 2, 3]), 6);
+});
+
+test('foldr', t => {
+  t.deepEqual(
+    Core.lists.foldr((v, acc) => acc + v.toString(), '', [1, 2, 3]),
+    '321'
+  );
+});
