add basic predicates

composer.json

@@ -20,7 +20,8 @@
             "Kadet\\Functional\\": "./src/"
         },
         "files": [
-            "./src/functions.php"
+            "./src/functions.php",
+            "./src/Predicates/index.php"
         ]
     }
 }

src/Predicate/AbstractPredicate.php

@@ -23,12 +23,12 @@ abstract class AbstractPredicate implements Predicate
     public function and(...$predicate): Predicate
     {
         array_unshift($predicate, $this);
-        return all($predicate);
+        return all(...$predicate);
     }
 
     public function or(...$predicate): Predicate
     {
         array_unshift($predicate, $this);
-        return any($predicate);
+        return any(...$predicate);
     }
 }

src/Predicate/AllOfPredicate.php

@@ -28,7 +28,7 @@ class AllOfPredicate extends AbstractPredicate
     public function and(...$predicate): Predicate
     {
         $predicate = array_merge($this->predicates, $predicate);
-        return parent::and($predicate);
+        return parent::and(...$predicate);
     }
 
     public function __invoke(...$args): bool

src/Predicate/AnyOfPredicate.php

@@ -28,7 +28,7 @@ class AnyOfPredicate extends AbstractPredicate
     public function or(...$predicate): Predicate
     {
         $predicate = array_merge($this->predicates, $predicate);
-        return parent::or($predicate);
+        return parent::or(...$predicate);
     }
 
 

src/Predicate/ConstantPredicate.php

@@ -23,7 +23,7 @@ class ConstantPredicate extends AbstractPredicate
      *
      * @param bool $value
      */
-    public function __construct(bool $value)
+    private function __construct(bool $value)
     {
         $this->value = $value;
     }
@@ -55,4 +55,14 @@ class ConstantPredicate extends AbstractPredicate
     {
         return $this->value;
     }
+
+    public static function always()
+    {
+        return new static(true);
+    }
+
+    public static function never()
+    {
+        return new static(false);
+    }
 }

src/Predicates/comparisons.php

@@ -0,0 +1,91 @@
+<?php
+/**
+ * Copyright 2018 Kacper Donat
+ *
+ * @author Kacper "Kadet" Donat <kacper@kadet.net>
+ *
+ * Full license available in separate LICENSE file
+ */
+
+namespace Kadet\Functional\Predicates;
+
+use Kadet\Functional\Predicate;
+use function Kadet\Functional\predicate;
+
+/**
+ * @param $expected
+ *
+ * @return \Kadet\Functional\Predicate
+ * @throws \Exception
+ */
+function equals($expected): Predicate
+{
+    return predicate(function ($value) use ($expected) {
+        return $expected == $value;
+    });
+}
+
+/**
+ * @param $expected
+ *
+ * @return \Kadet\Functional\Predicate
+ * @throws \Exception
+ */
+function same($expected): Predicate
+{
+    return predicate(function ($value) use ($expected) {
+        return $value === $expected;
+    });
+}
+
+/**
+ * @param $expected
+ *
+ * @return \Kadet\Functional\Predicate
+ * @throws \Exception
+ */
+function gt($expected): Predicate
+{
+    return predicate(function ($value) use ($expected) {
+        return $value > $expected;
+    });
+}
+
+/**
+ * @param $expected
+ *
+ * @return \Kadet\Functional\Predicate
+ * @throws \Exception
+ */
+function ge($expected): Predicate
+{
+    return predicate(function ($value) use ($expected) {
+        return $value >= $expected;
+    });
+}
+
+/**
+ * @param $expected
+ *
+ * @return \Kadet\Functional\Predicate
+ * @throws \Exception
+ */
+function lt($expected): Predicate
+{
+    return predicate(function ($value) use ($expected) {
+        return $value < $expected;
+    });
+}
+
+/**
+ * @param $expected
+ *
+ * @return \Kadet\Functional\Predicate
+ * @throws \Exception
+ */
+function le($expected): Predicate
+{
+    return predicate(function ($value) use ($expected) {
+        return $value <= $expected;
+    });
+}

src/Predicates/index.php

@@ -0,0 +1,11 @@
+<?php
+/**
+ * Copyright 2018 Kacper Donat
+ *
+ * @author Kacper "Kadet" Donat <kacper@kadet.net>
+ *
+ * Full license available in separate LICENSE file
+ */
+
+require_once __DIR__."/comparisons.php";
+require_once __DIR__."/objects.php";

src/Predicates/objects.php

@@ -0,0 +1,57 @@
+<?php
+/**
+ * Copyright 2018 Kacper Donat
+ *
+ * @author Kacper "Kadet" Donat <kacper@kadet.net>
+ *
+ * Full license available in separate LICENSE file
+ */
+
+namespace Kadet\Functional\Predicates;
+
+
+use function Kadet\Functional\predicate;
+use Kadet\Functional\Predicate\ClosurePredicate;
+
+/**
+ * @param string $method
+ * @param        $predicate
+ * @param array  $args
+ *
+ * @return \Kadet\Functional\Predicate
+ */
+function method(string $method, $predicate, ...$args)
+{
+    $predicate = predicate($predicate);
+
+    return new ClosurePredicate(function ($object) use ($method, $predicate, $args) {
+        return $predicate($object->{$method}($args));
+    });
+}
+
+/**
+ * @param string $property
+ * @param        $predicate
+ *
+ * @return \Kadet\Functional\Predicate
+ */
+function property(string $property, $predicate) {
+    $predicate = predicate($predicate);
+
+    return new ClosurePredicate(function ($object) use ($property, $predicate) {
+        if (isset($object->$property)) {
+            return $predicate($object->$property);
+        } elseif (method_exists($object, $getter = 'get'.ucfirst($property))) {
+            return $predicate($object->$getter());
+        } else {
+            return false;
+        }
+    });
+}
+
+function instance(string $class)
+{
+    return new ClosurePredicate(function ($value) use ($class) {
+        return $value instanceof $class;
+    });
+}

src/functions.php

@@ -11,20 +11,17 @@ use Kadet\Functional\Predicate\ConstantPredicate;
  * @param $predicate
  *
  * @return \Kadet\Functional\Predicate
- * @throws \Exception
  */
 function predicate($predicate): Predicate
 {
-    if ($predicate instanceof Predicate) {
-        return $predicate;
+    switch (true) {
+        case $predicate instanceof Predicate:
+            return $predicate;
+        case is_callable($predicate):
+            return new ClosurePredicate(\Closure::fromCallable($predicate));
+        default:
+            throw new \InvalidArgumentException('$predicate is not valid predicate.');
     }
-
-    if (is_callable($predicate)) {
-        return new ClosurePredicate(\Closure::fromCallable($predicate));
-    }
-
-    // todo better exception
-    throw new \Exception();
 }
 
 function not($predicate)
@@ -34,30 +31,29 @@ function not($predicate)
 
 function always()
 {
-    return new ConstantPredicate(true);
+    return ConstantPredicate::always();
 }
 
 function never()
 {
-    return new ConstantPredicate(false);
+    return ConstantPredicate::never();
+}
+
+function unpack($arguments)
+{
+    return count($arguments) === 1 && is_array(reset($arguments))
+        ? reset($arguments)
+        : $arguments;
 }
 
 function all(...$predicates)
 {
-    // extract array
-    if (count($predicates) === 1 && is_array($predicates[0])) {
-        $predicates = $predicates[0];
-    }
-
+    $predicates = unpack($predicates);
     return new AllOfPredicate(...array_map(predicate::class, $predicates));
 }
 
 function any(...$predicates)
 {
-    // extract array
-    if (count($predicates) === 1 && is_array($predicates[0])) {
-        $predicates = $predicates[0];
-    }
-
+    $predicates = unpack($predicates);
     return new AnyOfPredicate(...array_map(predicate::class, $predicates));
 }