Adding product fn

Signed-off-by: RJ Garcia <rj@bighead.net>
krakphp · Aug 5, 2019 · 9350d01 · 9350d01
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diff --git a/README.md b/README.md
@@ -226,7 +226,7 @@ The constants and curried functions are generated with `make code`.
 Tests are run via `make test` and are stored in the `test` directory. We use peridot for testing.
 
 ## API
-<table><tr><td><a href="#api-krak-fun-all">all</a></td><td><a href="#api-krak-fun-any">any</a></td><td><a href="#api-krak-fun-arraycompact">arrayCompact</a></td><td><a href="#api-krak-fun-arrayfilter">arrayFilter</a></td><td><a href="#api-krak-fun-arraymap">arrayMap</a></td><td><a href="#api-krak-fun-arrayreindex">arrayReindex</a></td><td><a href="#api-krak-fun-assign">assign</a></td><td><a href="#api-krak-fun-chain">chain</a></td></tr><tr><td><a href="#api-krak-fun-chunk">chunk</a></td><td><a href="#api-krak-fun-chunkby">chunkBy</a></td><td><a href="#api-krak-fun-compact">compact</a></td><td><a href="#api-krak-fun-compose">compose</a></td><td><a href="#api-krak-fun-construct">construct</a></td><td><a href="#api-krak-fun-curry">curry</a></td><td><a href="#api-krak-fun-differencewith">differenceWith</a></td><td><a href="#api-krak-fun-dd">dd</a></td></tr><tr><td><a href="#api-krak-fun-drop">drop</a></td><td><a href="#api-krak-fun-dropwhile">dropWhile</a></td><td><a href="#api-krak-fun-each">each</a></td><td><a href="#api-krak-fun-filter">filter</a></td><td><a href="#api-krak-fun-filterkeys">filterKeys</a></td><td><a href="#api-krak-fun-flatmap">flatMap</a></td><td><a href="#api-krak-fun-flatten">flatten</a></td><td><a href="#api-krak-fun-flip">flip</a></td></tr><tr><td><a href="#api-krak-fun-frompairs">fromPairs</a></td><td><a href="#api-krak-fun-groupby">groupBy</a></td><td><a href="#api-krak-fun-hasindexin">hasIndexIn</a></td><td><a href="#api-krak-fun-head">head</a></td><td><a href="#api-krak-fun-inarray">inArray</a></td><td><a href="#api-krak-fun-index">index</a></td><td><a href="#api-krak-fun-indexin">indexIn</a></td><td><a href="#api-krak-fun-indexof">indexOf</a></td></tr><tr><td><a href="#api-krak-fun-isnull">isNull</a></td><td><a href="#api-krak-fun-iter">iter</a></td><td><a href="#api-krak-fun-join">join</a></td><td><a href="#api-krak-fun-keys">keys</a></td><td><a href="#api-krak-fun-map">map</a></td><td><a href="#api-krak-fun-mapaccum">mapAccum</a></td><td><a href="#api-krak-fun-mapkeys">mapKeys</a></td><td><a href="#api-krak-fun-mapkeyvalue">mapKeyValue</a></td></tr><tr><td><a href="#api-krak-fun-mapon">mapOn</a></td><td><a href="#api-krak-fun-nullable">nullable</a></td><td><a href="#api-krak-fun-oneach">onEach</a></td><td><a href="#api-krak-fun-op">op</a></td><td><a href="#api-krak-fun-pad">pad</a></td><td><a href="#api-krak-fun-partial">partial</a></td><td><a href="#api-krak-fun-partition">partition</a></td><td><a href="#api-krak-fun-pipe">pipe</a></td></tr><tr><td><a href="#api-krak-fun-prop">prop</a></td><td><a href="#api-krak-fun-propin">propIn</a></td><td><a href="#api-krak-fun-range">range</a></td><td><a href="#api-krak-fun-reduce">reduce</a></td><td><a href="#api-krak-fun-reducekeyvalue">reduceKeyValue</a></td><td><a href="#api-krak-fun-reindex">reindex</a></td><td><a href="#api-krak-fun-retry">retry</a></td><td><a href="#api-krak-fun-search">search</a></td></tr><tr><td><a href="#api-krak-fun-setindex">setIndex</a></td><td><a href="#api-krak-fun-setindexin">setIndexIn</a></td><td><a href="#api-krak-fun-setprop">setProp</a></td><td><a href="#api-krak-fun-slice">slice</a></td><td><a href="#api-krak-fun-sortfromarray">sortFromArray</a></td><td><a href="#api-krak-fun-spread">spread</a></td><td><a href="#api-krak-fun-take">take</a></td><td><a href="#api-krak-fun-takewhile">takeWhile</a></td></tr><tr><td><a href="#api-krak-fun-toarray">toArray</a></td><td><a href="#api-krak-fun-toarraywithkeys">toArrayWithKeys</a></td><td><a href="#api-krak-fun-topairs">toPairs</a></td><td><a href="#api-krak-fun-updateindexin">updateIndexIn</a></td><td><a href="#api-krak-fun-values">values</a></td><td><a href="#api-krak-fun-when">when</a></td><td><a href="#api-krak-fun-withstate">withState</a></td><td><a href="#api-krak-fun-within">within</a></td></tr><tr><td><a href="#api-krak-fun-without">without</a></td><td><a href="#api-krak-fun-zip">zip</a></td></tr></table>
+<table><tr><td><a href="#api-krak-fun-all">all</a></td><td><a href="#api-krak-fun-any">any</a></td><td><a href="#api-krak-fun-arraycompact">arrayCompact</a></td><td><a href="#api-krak-fun-arrayfilter">arrayFilter</a></td><td><a href="#api-krak-fun-arraymap">arrayMap</a></td><td><a href="#api-krak-fun-arrayreindex">arrayReindex</a></td><td><a href="#api-krak-fun-assign">assign</a></td><td><a href="#api-krak-fun-chain">chain</a></td></tr><tr><td><a href="#api-krak-fun-chunk">chunk</a></td><td><a href="#api-krak-fun-chunkby">chunkBy</a></td><td><a href="#api-krak-fun-compact">compact</a></td><td><a href="#api-krak-fun-compose">compose</a></td><td><a href="#api-krak-fun-construct">construct</a></td><td><a href="#api-krak-fun-curry">curry</a></td><td><a href="#api-krak-fun-differencewith">differenceWith</a></td><td><a href="#api-krak-fun-dd">dd</a></td></tr><tr><td><a href="#api-krak-fun-drop">drop</a></td><td><a href="#api-krak-fun-dropwhile">dropWhile</a></td><td><a href="#api-krak-fun-each">each</a></td><td><a href="#api-krak-fun-filter">filter</a></td><td><a href="#api-krak-fun-filterkeys">filterKeys</a></td><td><a href="#api-krak-fun-flatmap">flatMap</a></td><td><a href="#api-krak-fun-flatten">flatten</a></td><td><a href="#api-krak-fun-flip">flip</a></td></tr><tr><td><a href="#api-krak-fun-frompairs">fromPairs</a></td><td><a href="#api-krak-fun-groupby">groupBy</a></td><td><a href="#api-krak-fun-hasindexin">hasIndexIn</a></td><td><a href="#api-krak-fun-head">head</a></td><td><a href="#api-krak-fun-inarray">inArray</a></td><td><a href="#api-krak-fun-index">index</a></td><td><a href="#api-krak-fun-indexin">indexIn</a></td><td><a href="#api-krak-fun-indexof">indexOf</a></td></tr><tr><td><a href="#api-krak-fun-isnull">isNull</a></td><td><a href="#api-krak-fun-iter">iter</a></td><td><a href="#api-krak-fun-join">join</a></td><td><a href="#api-krak-fun-keys">keys</a></td><td><a href="#api-krak-fun-map">map</a></td><td><a href="#api-krak-fun-mapaccum">mapAccum</a></td><td><a href="#api-krak-fun-mapkeys">mapKeys</a></td><td><a href="#api-krak-fun-mapkeyvalue">mapKeyValue</a></td></tr><tr><td><a href="#api-krak-fun-mapon">mapOn</a></td><td><a href="#api-krak-fun-nullable">nullable</a></td><td><a href="#api-krak-fun-oneach">onEach</a></td><td><a href="#api-krak-fun-op">op</a></td><td><a href="#api-krak-fun-pad">pad</a></td><td><a href="#api-krak-fun-partial">partial</a></td><td><a href="#api-krak-fun-partition">partition</a></td><td><a href="#api-krak-fun-pipe">pipe</a></td></tr><tr><td><a href="#api-krak-fun-product">product</a></td><td><a href="#api-krak-fun-prop">prop</a></td><td><a href="#api-krak-fun-propin">propIn</a></td><td><a href="#api-krak-fun-range">range</a></td><td><a href="#api-krak-fun-reduce">reduce</a></td><td><a href="#api-krak-fun-reducekeyvalue">reduceKeyValue</a></td><td><a href="#api-krak-fun-reindex">reindex</a></td><td><a href="#api-krak-fun-retry">retry</a></td></tr><tr><td><a href="#api-krak-fun-search">search</a></td><td><a href="#api-krak-fun-setindex">setIndex</a></td><td><a href="#api-krak-fun-setindexin">setIndexIn</a></td><td><a href="#api-krak-fun-setprop">setProp</a></td><td><a href="#api-krak-fun-slice">slice</a></td><td><a href="#api-krak-fun-sortfromarray">sortFromArray</a></td><td><a href="#api-krak-fun-spread">spread</a></td><td><a href="#api-krak-fun-take">take</a></td></tr><tr><td><a href="#api-krak-fun-takewhile">takeWhile</a></td><td><a href="#api-krak-fun-toarray">toArray</a></td><td><a href="#api-krak-fun-toarraywithkeys">toArrayWithKeys</a></td><td><a href="#api-krak-fun-topairs">toPairs</a></td><td><a href="#api-krak-fun-updateindexin">updateIndexIn</a></td><td><a href="#api-krak-fun-values">values</a></td><td><a href="#api-krak-fun-when">when</a></td><td><a href="#api-krak-fun-withstate">withState</a></td></tr><tr><td><a href="#api-krak-fun-within">within</a></td><td><a href="#api-krak-fun-without">without</a></td><td><a href="#api-krak-fun-zip">zip</a></td></tr></table>
 
 <h3 id="api-krak-fun-all">all(callable $predicate, iterable $iter): bool</h3>
 
@@ -623,6 +623,13 @@ $res = flatten([1, [2, [3]]], 1);
 expect(toArray($res))->equal([1, 2, [3]]);
 ```
 
+Flattening zero levels does nothing:
+
+```php
+$res = flatten([1, [2]], 0);
+expect(toArray($res))->equal([1, [2]]);
+```
+
 
 
 <h3 id="api-krak-fun-flip">flip(iterable $iter): iterable</h3>
@@ -1167,6 +1174,19 @@ expect($res)->equal(6);
 
 `pipe` and `compose` are sister functions and do the same thing except the functions are composed in reverse order. pipe(f, g)(x) = g(f(x))
 
+<h3 id="api-krak-fun-product">product(iterable ...$iters): iterable</h3>
+
+**Name:** `Krak\Fun\product`
+
+Creates a cartesian product of multiple sets:
+
+```php
+$res = product([1, 2], [3, 4], [5, 6]);
+expect(toArray($res))->equal([[1, 3, 5], [1, 3, 6], [1, 4, 5], [1, 4, 6], [2, 3, 5], [2, 3, 6], [2, 4, 5], [2, 4, 6]]);
+```
+
+
+
 <h3 id="api-krak-fun-prop">prop(string $key, $data, $else = null)</h3>
 
 **Name:** `Krak\Fun\prop`

diff --git a/src/c.generated.php b/src/c.generated.php
@@ -329,7 +329,7 @@ function flatten($levels = INF)
 {
     return function (iterable $iter) use($levels) {
         if ($levels == 0) {
-            return $iter;
+            yield from $iter;
         } else {
             if ($levels == 1) {
                 foreach ($iter as $k => $v) {
@@ -741,6 +741,7 @@ function onEach(callable $handle)
 const zip = 'Krak\\Fun\\zip';
 const flatMap = 'Krak\\Fun\\flatMap';
 const flatten = 'Krak\\Fun\\flatten';
+const product = 'Krak\\Fun\\product';
 const when = 'Krak\\Fun\\when';
 const toPairs = 'Krak\\Fun\\toPairs';
 const fromPairs = 'Krak\\Fun\\fromPairs';

diff --git a/src/consts.generated.php b/src/consts.generated.php
@@ -35,6 +35,7 @@
 const zip = 'Krak\\Fun\\zip';
 const flatMap = 'Krak\\Fun\\flatMap';
 const flatten = 'Krak\\Fun\\flatten';
+const product = 'Krak\\Fun\\product';
 const when = 'Krak\\Fun\\when';
 const toPairs = 'Krak\\Fun\\toPairs';
 const fromPairs = 'Krak\\Fun\\fromPairs';

diff --git a/src/consts.ns.generated.php b/src/consts.ns.generated.php
@@ -35,6 +35,7 @@
 const zip = 'Krak\\Fun\\zip';
 const flatMap = 'Krak\\Fun\\flatMap';
 const flatten = 'Krak\\Fun\\flatten';
+const product = 'Krak\\Fun\\product';
 const when = 'Krak\\Fun\\when';
 const toPairs = 'Krak\\Fun\\toPairs';
 const fromPairs = 'Krak\\Fun\\fromPairs';

diff --git a/src/curried.generated.php b/src/curried.generated.php
@@ -329,7 +329,7 @@ function flatten($levels = INF)
 {
     return function (iterable $iter) use($levels) {
         if ($levels == 0) {
-            return $iter;
+            yield from $iter;
         } else {
             if ($levels == 1) {
                 foreach ($iter as $k => $v) {

diff --git a/src/f.generated.php b/src/f.generated.php
@@ -325,7 +325,7 @@ function flatMap(callable $map, iterable $iter) : iterable
 function flatten(iterable $iter, $levels = INF) : iterable
 {
     if ($levels == 0) {
-        return $iter;
+        yield from $iter;
     } else {
         if ($levels == 1) {
             foreach ($iter as $k => $v) {
@@ -350,6 +350,25 @@ function flatten(iterable $iter, $levels = INF) : iterable
         }
     }
 }
+function product(iterable ...$iters) : iterable
+{
+    if (count($iters) === 0) {
+        yield from [];
+        return;
+    }
+    if (count($iters) === 1) {
+        yield from \Krak\Fun\map(function ($v) {
+            return [$v];
+        }, $iters[0]);
+        return;
+    }
+    foreach ($iters[0] as $value) {
+        yield from \Krak\Fun\map(function (array $tup) use($value) {
+            array_unshift($tup, $value);
+            return $tup;
+        }, \Krak\Fun\product(...\array_slice($iters, 1)));
+    }
+}
 function when(callable $if, callable $then, $value)
 {
     return $if($value) ? $then($value) : $value;

diff --git a/src/fn.php b/src/fn.php
@@ -338,7 +338,7 @@ function flatMap(callable $map, iterable $iter): iterable {
 
 function flatten(iterable $iter, $levels = INF): iterable {
     if ($levels == 0) {
-        return $iter;
+        yield from $iter;
     } else if ($levels == 1) {
         foreach ($iter as $k => $v) {
             if (\is_iterable($v)) {
@@ -363,6 +363,25 @@ function flatten(iterable $iter, $levels = INF): iterable {
 }
 
 
+function product(iterable ...$iters): iterable {
+    if (count($iters) === 0) {
+        yield from [];
+        return;
+    }
+    if (count($iters) === 1) {
+        yield from \Krak\Fun\map(function($v) { return [$v]; }, $iters[0]);
+        return;
+    }
+
+    foreach ($iters[0] as $value) {
+        yield from \Krak\Fun\map(function(array $tup) use ($value) {
+            array_unshift($tup, $value);
+            return $tup;
+        }, \Krak\Fun\product(...\array_slice($iters, 1)));
+    }
+}
+
+
 function when(callable $if, callable $then, $value) {
     return $if($value) ? $then($value) : $value;
 }

diff --git a/test/fn.spec.php b/test/fn.spec.php
@@ -284,6 +284,10 @@ function() { yield from [1,2,3]; }
             $res = flatten([1,[2, [3]]], 1);
             expect(toArray($res))->equal([1, 2, [3]]);
         });
+        test('Flattening zero levels does nothing', function() {
+            $res = flatten([1, [2]], 0);
+            expect(toArray($res))->equal([1,[2]]);
+        });
     });
     describe('flip', function() {
         docFn(flip::class);
@@ -680,6 +684,23 @@ function() { yield from [1,2,3]; },
 
         docOutro('`pipe` and `compose` are sister functions and do the same thing except the functions are composed in reverse order. pipe(f, g)(x) = g(f(x))');
     });
+    describe('product', function() {
+        docFn(product::class);
+
+        test('Creates a cartesian product of multiple sets', function() {
+            $res = product([1,2], [3,4], [5, 6]);
+            expect(toArray($res))->equal([
+                [1,3,5],
+                [1,3,6],
+                [1,4,5],
+                [1,4,6],
+                [2,3,5],
+                [2,3,6],
+                [2,4,5],
+                [2,4,6],
+            ]);
+        });
+    });
     describe('prop', function() {
         docFn(prop::class);