Structs in PHP. Work in progress.

example.php

<?php

require("struct.php");

class FooClass
{
    use Struct;
    public $property;
}

class MyStruct
{
    use Struct;

    /** @var FooClass */
    public $foo_class;

    /** @var integer */
    public $bar_int;

    /** @var Testing\Bar */
    public $baz;
}

$tmp = new MyStruct(new FooClass("anything works here"), 456, new Testing\Bar());

struct.php

<?php

trait Struct {

    private function structGetTypeHint($docCommOutput)
    {
        if ($docCommOutput == null) {
            return null;
        }
        if (preg_match('/@var\s+([^\s\*]+)/', $docCommOutput, $matches)) {
            list(, $type) = $matches;
            return $type;
        }
        return null;
    }

    private function structAssignArgs($args)
    {
        $refl = new \ReflectionClass($this);
        $props = $refl->getProperties(ReflectionProperty::IS_PUBLIC);
        foreach ($props as $prop) {
            $val = null;
            if (count($args) > 0) {
                $val = array_shift($args);
            }
            $docComm = $prop->getDocComment();
            $typeHint = $this->structGetTypeHint($docComm);
            $valType = is_object($val) ? get_class($val) : gettype($val);
            if ($typeHint !== null && $valType != $typeHint) {
                $name = $prop->getName();
                throw new \Exception("Type mismatch: property {$name} must be of type {$typeHint} but was {$valType}.");
            }
            $prop->setValue($this, $val);
        }
    }

    public function __construct()
    {
        // would prefer C extension "phpstruct_treat_args_as_property_assignment()"
        $this->structAssignArgs(func_get_args());
    }
}

TODO.md

PHP Struct Trait

This should really be a C extension but this is an OK prototype of the concept. Structs in PHP!

TODO

• Add magic setter to enforce type safety.
• Like, maybe typed arrays?
• Probably static caching the reflection info so we don't have to do the reflection dance on each instantiation.