DEV Čtvrtkon #76 - Fluent Interface

PROBLÉM SKLÁDÁNÍ FUNKCÍ A OBJEKTŮ - POSTFIX NOTACE
$json = new ParseJson( 
new AssertResponseStatus( 
new RequestWithHeader( 
new AuthHeader('basic', $username, $password), 
new RequestWithMethod( 
'GET', 
new Request('example.com') 
) 
), 
200 
) 
).toString();

TEXT
FLUENT INTEFACE
class Request { 
// ... 
function withMethod($method) { 
$this->method = $method; 
return $this; 
} 
// ... 
}

TEXT
FLUENT INTEFACE
$json = new Request('example.com') 
->withMethod('GET') 
->withHeader(new AuthHeader('basic', $username, $password)) 
->assertResponseStatus(200) 
->parseJson() 
->toString();

THE API IS PRIMARILY DESIGNED TO BE
READABLE AND TO FLOW. THE PRICE OF THIS
FLUENCY IS MORE EFFORT, BOTH IN THINKING
AND IN THE API CONSTRUCTION ITSELF.
Martin Fowler
TEXT

TEXT
NEVÝHODY FLUENT INTERFACE
‣Špatná rozšiřitelnost
‣Nemožnost spojit do "fluentu" více rozhraní
‣Proxy / dekorátory a "unwrapnutí" $this!

TEXT
UNWRAP
class FluentCounter { 
$i = 0; 
function inc() { 
$this->i++; 
return $this; 
} 
} 
 
class LoggerCounter { 
$this->counter = new FluentCounter(); 
function inc() { 
echo "calling incn"; 
return $this->counter->inc(); 
} 
} 
 
new LoggerCounter(new FluentCounter())->inc()->inc()->inc(); // "calling inc" (jednou)

TEXT
UNWRAP
class FluentCounter { 
$i = 0; 
function inc() { 
$this->i++; 
return $this; 
} 
} 
 
class LoggerCounter { 
$this->counter = new FluentCounter(); 
function inc() { 
echo "calling incn"; 
$this->counter = $this->counter->inc(); 
return $this; 
} 
} 
 
new LoggerCounter(new FluentCounter())->inc()->inc()->inc(); // "calling inc" (třikrát)

TEXT
NEŠLO BY PROSTĚ OTOČIT POŘADÍ?
function revert2($fn1, $fn2) { 
return function (...$args) use ($fn1, $fn2) { 
return $fn2($fn1(...$args)); 
}; 
}
function fn1($x) { 
return 'fn1(' . $x . ')'; 
} 
 
function fn2($x) { 
return 'fn2(' . $x . ')'; 
} 
 
echo revert2('fn1', 'fn2')('x'); // 'fn2(fn1(x))'

TEXT
JAK TO UDĚLAT PRO N FUNKCÍ?

TEXT
JAK TO UDĚLAT PRO N FUNKCÍ?
function revert2($fn1, $fn2) { 
return function (...$args) use ($fn1, $fn2) { 
return $fn2($fn1(...$args)); 
}; 
}
function revert($f1, ...$fns) { 
return array_reduce($fns, 'revert2', $f1); 
}
// ﬁnal version:
function revert($f1, ...$fns) { 
return array_reduce($fns, function ($fn1, $fn2) { 
return function (...$args) use ($fn1, $fn2) { return $fn2($fn1(...$args)); }; 
}, $f1); 
}

TEXT
POUŽITÍ
$json = pipe( 
new Request('example.com'), 
new WithMethod('GET'), 
new WithHeader(new AuthHeader('basic', $username, $password), 
new AssertResponseStatus(200), 
new ParseJson(), 
)->toString();
// s pipe operátorem:
$json = new Request('example.com') 
|> new WithMethod($$, 'GET'), 
|> new WithHeader(new AuthHeader('basic', $username, $password), $$), 
|> new AssertResponseStatus($$, 200), 
|> new ParseJson(), 
|> toString();

TEXT
PIPE OPERÁTOR V OSTATNÍCH JAZYCÍCH
▸ PHP: https://wiki.php.net/rfc/pipe-operator
▸ javascript: https://github.com/tc39/proposal-pipeline-
operator
▸ C#: https://github.com/dotnet/csharplang/issues/96
▸ ...

DEV Čtvrtkon #76 - Fluent Interface

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DEV Čtvrtkon #76 - Fluent Interface