Implement map for decoders

CHANGELOG.md

@@ -5,8 +5,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- `trasformValidationSuccess` function for decoders. Structurally equivalent to a map. (#24)
 ### Fixed
-- Used Psalm specific annotations to avoid confusing IDEs without Psalm support. (#26) 
+- Used Psalm specific annotations to avoid confusing IDEs without Psalm support. (#26)
+### Deprecated
+- Usage of codecs is deprecated in favour of decoders. (#24)
 
 ## [0.0.1] - 2021-04-30 
 ### Added

Makefile

@@ -11,7 +11,7 @@ sh:
 	docker-compose exec php bash
 
 psalm:
-	./vendor/bin/psalm --no-cache
+	./vendor/bin/psalm src --no-cache
 
 type-assertions:
 	./vendor/bin/psalm tests/type-assertions --no-cache

src/Codecs.php

@@ -14,14 +14,15 @@
 use Facile\PhpCodec\Internal\Primitives\BoolType;
 use Facile\PhpCodec\Internal\Primitives\CallableDecoder;
 use Facile\PhpCodec\Internal\Primitives\FloatType;
-use Facile\PhpCodec\Internal\Primitives\IntType;
+use Facile\PhpCodec\Internal\Primitives\IntDecoder;
 use Facile\PhpCodec\Internal\Primitives\MixedDecoder;
 use Facile\PhpCodec\Internal\Primitives\NullType;
 use Facile\PhpCodec\Internal\Primitives\StringType;
 use Facile\PhpCodec\Internal\Primitives\UndefinedDecoder;
 use Facile\PhpCodec\Internal\Useful\DateTimeFromIsoStringType;
-use Facile\PhpCodec\Internal\Useful\IntFromStringType;
+use Facile\PhpCodec\Internal\Useful\IntFromStringDecoder;
 use Facile\PhpCodec\Internal\Useful\RegexType;
+use Facile\PhpCodec\Utils\ConcreteCodec;
 
 final class Codecs
 {
@@ -42,11 +43,15 @@ public static function string(): Codec
     }
 
     /**
-     * @psalm-return Codec<int, mixed, int>
+     * @template I of mixed
+     * @psalm-return Codec<int, I, int>
+     *
+     * @deprecated use decoder instead
+     * @see Decoders::int()
      */
     public static function int(): Codec
     {
-        return new IntType();
+        return self::fromDecoder(new IntDecoder());
     }
 
     /**
@@ -79,10 +84,13 @@ public static function literal($x): Codec
 
     /**
      * @psalm-return Codec<int, string, int>
+     *
+     * @deprecated use decoder instead
+     * @see Decoders::intFromString()
      */
     public static function intFromString(): Codec
     {
-        return new IntFromStringType();
+        return self::fromDecoder(new IntFromStringDecoder());
     }
 
     /**
@@ -200,6 +208,9 @@ public static function fromDecoder(Decoder $decoder): Codec
      * @psalm-return Codec<U, mixed, U>
      *
      * @param null|mixed $default
+     *
+     * @deprecated use decoder instead
+     * @see Decoders::undefined()
      */
     public static function undefined($default = null): Codec
     {
@@ -209,6 +220,9 @@ public static function undefined($default = null): Codec
     /**
      * @psalm-template U of mixed
      * @psalm-return Codec<U, mixed, U>
+     *
+     * @deprecated use decoder instead
+     * @see Decoders::mixed()
      */
     public static function mixed(): Codec
     {
@@ -217,6 +231,9 @@ public static function mixed(): Codec
 
     /**
      * @psalm-return Codec<callable, mixed, callable>
+     *
+     * @deprecated use decoder instead
+     * @see Decoders::callable()
      */
     public static function callable(): Codec
     {

src/Decoders.php

@@ -4,14 +4,70 @@
 
 namespace Facile\PhpCodec;
 
+use Facile\PhpCodec\Internal\Combinators\ComposeDecoder;
+use Facile\PhpCodec\Internal\Combinators\MapDecoder;
+use Facile\PhpCodec\Internal\Primitives\CallableDecoder;
+use Facile\PhpCodec\Internal\Primitives\IntDecoder;
+use Facile\PhpCodec\Internal\Primitives\MixedDecoder;
 use Facile\PhpCodec\Internal\Primitives\UndefinedDecoder;
+use Facile\PhpCodec\Internal\Useful\IntFromStringDecoder;
+use Facile\PhpCodec\Utils\ConcreteDecoder;
+use Facile\PhpCodec\Validation\Context;
+use Facile\PhpCodec\Validation\Validation;
 
 final class Decoders
 {
     private function __construct()
     {
     }
 
+    /**
+     * @template I
+     * @template A
+     * @psalm-param callable(I, Context):Validation<A> $f
+     * @psalm-param string $name
+     * @psalm-return Decoder<I, A>
+     */
+    public static function make(callable $f, string $name = 'anon'): Decoder
+    {
+        return new ConcreteDecoder($f, $name);
+    }
+
+    /**
+     * @template I
+     * @template A
+     * @template B
+     * @psalm-param Decoder<A, B> $db
+     * @psalm-param Decoder<I, A> $da
+     * @psalm-return Decoder<I, B>
+     */
+    public static function compose(Decoder $db, Decoder $da): Decoder
+    {
+        return new ComposeDecoder($db, $da);
+    }
+
+    /**
+     * This is structurally equivalent to a map function
+     * map :: (a -> b) -> Decoder a -> Decoder b
+     *
+     * I still don't know if decoders could be functors or something more complicated.
+     * By now, let me introduce it with this strange name. I just need this feature.
+     *
+     * @template I
+     * @template A
+     * @template B
+     * @psalm-param callable(A):B $f
+     * @psalm-param Decoder<I, A> $da
+     * @psalm-return Decoder<I, B>
+     */
+    public static function transformValidationSuccess(callable $f, Decoder $da): Decoder
+    {
+        return self::compose(
+            new MapDecoder($f, $da->getName()),
+            $da
+        );
+    }
+
     /**
      * @psalm-template U
      * @psalm-param U $default
@@ -23,4 +79,36 @@ public static function undefined($default = null): Decoder
     {
         return new UndefinedDecoder($default);
     }
+
+    /**
+     * @psalm-return Decoder<mixed, int>
+     */
+    public static function int(): Decoder
+    {
+        return new IntDecoder();
+    }
+
+    /**
+     * @psalm-return Decoder<string, int>
+     */
+    public static function intFromString(): Decoder
+    {
+        return new IntFromStringDecoder();
+    }
+
+    /**
+     * @psalm-return Decoder<mixed, mixed>
+     */
+    public static function mixed(): Decoder
+    {
+        return new MixedDecoder();
+    }
+
+    /**
+     * @psalm-return Decoder<mixed, callable>
+     */
+    public static function callable(): Decoder
+    {
+        return new CallableDecoder();
+    }
 }

src/Internal/Combinators/ComposeDecoder.php

@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Facile\PhpCodec\Internal\Combinators;
+
+use Facile\PhpCodec\Decoder;
+use function Facile\PhpCodec\Internal\standardDecode;
+use Facile\PhpCodec\Validation\Context;
+use Facile\PhpCodec\Validation\Validation;
+
+/**
+ * @psalm-template IA
+ * @psalm-template A
+ * @psalm-template B
+ *
+ * @template-implements Decoder<IA, B>
+ */
+class ComposeDecoder implements Decoder
+{
+    /** @var Decoder<A, B> */
+    private $db;
+    /** @var Decoder<IA, A> */
+    private $da;
+
+    /**
+     * @psalm-param Decoder<A, B> $db
+     * @psalm-param Decoder<IA, A> $da
+     */
+    public function __construct(
+        Decoder $db,
+        Decoder $da
+    ) {
+        $this->db = $db;
+        $this->da = $da;
+    }
+
+    /**
+     * @psalm-param IA      $i
+     * @psalm-param Context $context
+     * @psalm-return Validation<B>
+     *
+     * @param mixed $i
+     */
+    public function validate($i, Context $context): Validation
+    {
+        return Validation::bind(
+            /**
+             * @psalm-param A $aValue
+             *
+             * @param mixed $aValue
+             */
+            function ($aValue) use ($context): Validation {
+                return $this->db->validate($aValue, $context);
+            },
+            $this->da->validate($i, $context)
+        );
+    }
+
+    public function decode($i): Validation
+    {
+        return standardDecode($this, $i);
+    }
+
+    public function getName(): string
+    {
+        return $this->db->getName();
+    }
+}

src/Internal/Combinators/MapDecoder.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Facile\PhpCodec\Internal\Combinators;
+
+use Facile\PhpCodec\Decoder;
+use function Facile\PhpCodec\Internal\standardDecode;
+use Facile\PhpCodec\Validation\Context;
+use Facile\PhpCodec\Validation\Validation;
+
+/**
+ * @template A
+ * @template B
+ * @implements Decoder<A, B>
+ */
+class MapDecoder implements Decoder
+{
+    /** @var callable(A):B */
+    private $f;
+    /** @var string */
+    private $name;
+
+    /**
+     * @psalm-param callable(A):B $f
+     *
+     * @param callable $f
+     */
+    public function __construct(callable $f, string $name = 'map')
+    {
+        $this->f = $f;
+        $this->name = $name;
+    }
+
+    public function validate($i, Context $context): Validation
+    {
+        return Validation::success(($this->f)($i));
+    }
+
+    public function decode($i): Validation
+    {
+        return standardDecode($this, $i);
+    }
+
+    public function getName(): string
+    {
+        return $this->name;
+    }
+}

src/Internal/Primitives/IntDecoder.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Facile\PhpCodec\Internal\Primitives;
+
+use Facile\PhpCodec\Decoder;
+use function Facile\PhpCodec\Internal\standardDecode;
+use Facile\PhpCodec\Validation\Context;
+use Facile\PhpCodec\Validation\Validation;
+
+/**
+ * @template I of mixed
+ * @implements Decoder<I, int>
+ */
+class IntDecoder implements Decoder
+{
+    public function validate($i, Context $context): Validation
+    {
+        return \is_int($i)
+            ? Validation::success($i)
+            : Validation::failure($i, $context);
+    }
+
+    public function decode($i): Validation
+    {
+        return standardDecode($this, $i);
+    }
+
+    public function getName(): string
+    {
+        return 'int';
+    }
+}

src/Internal/Primitives/IntRefiner.php

@@ -8,6 +8,8 @@
 
 /**
  * @implements Refiner<int>
+ *
+ * @deprecated
  */
 class IntRefiner implements Refiner
 {