Programming in handstand

Programming in handstand

PHP Meetup, 2014. 04. 23.


Attila Magyar (@athoshun)http://athoshun.eu

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http://balabit.com

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http://balabit.com

Rafael Ördög (@devillsroom)http://c0de-x.comhttp://leanpoker.org

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http://balabit.com


http://coderetreat.orghttp://www.meetup.com/Coderetreat-Budapest/

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http://balabit.com


http://coderetreat.orghttp://www.meetup.com/Coderetreat-Budapest/

Gergely Nagy (@algernoone)http://asylum.madhouse-project.org/http://syslog-ng.org/

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FizzBuzz

Write a program that iterates through the numbers from 1 to 100 and:

For multiples of 3 print "Fizz" For multiples of 5 print "Buzz" For numbers which are multiples of both 3

and 5 print "FizzBuzz" For others, print the number itself

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FizzBuzz

Write a program that iterates through the numbers from 1 to 100 and:

For multiples of 3 print "Fizz" For multiples of 5 print "Buzz" For numbers which are multiples of both 3

and 5 print "FizzBuzz" For others, print the number itself

1, 2, Fizz, 4, Buzz, Fizz, 7, 8, Fizz, Buzz,11, Fizz, 13, 14, FizzBuzz, 16, 17, Fizz, 19,Buzz, Fizz, 22, 23, Fizz, Buzz, 26, Fizz, 28,29, FizzBuzz, ...

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FizzBuzz

for ($i = 0; $i < 100; ++$i) {

if ($i % 3 === 0) { print "Fizz"; } if ($i % 5 === 0) { print "Buzz"; } if ($i % 3 !== 0 && $i % 5 !== 0) { print $i; }

print ", "; }

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FizzBuzz

for ($i = 0; $i < 100; ++$i) {

if ($i % 3 === 0) { print "Fizz"; } if ($i % 5 === 0) { print "Buzz"; } if ($i % 3 !== 0 && $i % 5 !== 0) { print $i; }

print ", "; }

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FizzBuzzfunction fizzbuzz(){ $sequence = array();

for ($i = 0; $i < 100; ++$i) { $formatted = "";

if ($i % 3 === 0) { $formatted .= "Fizz"; } if ($i % 5 === 0) { $formatted .= "Buzz"; } if ($i % 3 !== 0 && $i % 5 !== 0) { $formatted = "$i"; }

$sequence[] = $formatted; }

return $sequence;}

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return $sequence;}

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return $sequence;}

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return $sequence;}

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if ($i % 3 === 0) { $formatted .= "Fizz"; } if ($i % 5 === 0) { $formatted .= "Buzz"; } if ($formatted === "") { $formatted = "$i"; }


return $sequence;}

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FizzBuzzBeepfunction fizzbuzz(){ $sequence = array();




return $sequence;}

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FizzBuzzBeepfunction fizzbuzz($with_beep = false){ $sequence = array();


if ($i % 3 === 0) $formatted .= "Fizz"; if ($i % 5 === 0) $formatted .= "Buzz"; if ($with_beep && $i % 7 === 0) $formatted .= "Beep"; if ($formatted === "") { $formatted = "$i"; }


return $sequence;}

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FizzBuzzBeepfunction fizzbuzz($with_beep = false, $with_digits = false){ $sequence = array();


if ($i % 3 === 0 || ($with_digits && strpos...)) $formatted .= "Fizz"; if ($i % 5 === 0 || ($with_digits && strpos...)) $formatted .= "Buzz"; if ($with_beep && $i % 7 === 0 || ($with_digits ...)) $formatted .= "Beep"; if ($formatted === "") { $formatted = "$i"; }


return $sequence;}

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FizzBuzzBeepfunction fizzbuzz($with_beep = false, $with_digits = false){ $sequence = array();


if ($i % 3 === 0 || ($with_digits && strpos...)) $formatted .= "Fizz"; if ($i % 5 === 0 || ($with_digits && strpos...)) $formatted .= "Buzz"; if ($with_beep && $i % 7 === 0 || ($with_digits ...)) $formatted .= "Beep"; if ($formatted === "") { $formatted = "$i"; }


return $sequence;}

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No loops!20/149

No loops!21/149

No loops!function fizzbuzz(){ $sequence = array();




return $sequence;}

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No loops!function fizzbuzz($i = 1, array $result = array()){ if ($i > 100) return $result;

$formatted = ""; if ($i % 3 === 0) { $formatted .= "Fizz"; } if ($i % 5 === 0) { $formatted .= "Buzz"; } if ($formatted === "") { $formatted .= "$i"; }

return fizzbuzz( $i + 1, array_merge($result, array($formatted)) );}

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No loops!function fizzbuzz($i = 1, array $result = array()){ if ($i > 100) return $result;

$formatted = ""; if ($i % 3 === 0) { $formatted .= "Fizz"; } if ($i % 5 === 0) { $formatted .= "Buzz"; } if ($formatted === "") { $formatted .= "$i"; }

return fizzbuzz( $i + 1, array_merge($result, array($formatted)) );}

PHP Fatal error: Maximumfunction nesting levelof '100' Reached, aborting!

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return $sequence;}

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array_map($callable, $array)function fizzbuzz(){ $sequence = array();




return $sequence;}

array_map( function ($x) { return 2*$x; }, array(1, 2, 3));

// array(2, 4, 6)

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return $sequence;}


// array(2, 4, 6)

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No loops!function fizzbuzz(){ return array_map( function ($i) {

$formatted = "";


return $formatted; }, range(1, 100) );}


// array(2, 4, 6)

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No loops!function fizzbuzz(){ return array_map( function ($i) {

$formatted = "";



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Still complex, rigidfunction fizzbuzz($with_beep = false, $with_digits = false){ return array_map( function ($i) use ($with_beep, $with_digits) {

$formatted = "";

if ($i % 3 === 0 || ($with_digits && strpos...)) $formatted .= "Fizz"; if ($i % 5 === 0 || ($with_digits && strpos...)) $formatted .= "Buzz"; if ($with_beep && (...)) $formatted .= "Buzz"; if ($formatted === "") $formatted = "$i";


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No conditional statements!function fizzbuzz(){ return array_map( function ($i) {

$formatted = "";



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Create some duplicationfunction fizzbuzz(){ return array_map( function ($i) {

$formatted = "";



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Create some duplicationfunction fizzbuzz(){ return array_map( function ($i) {

$formatted = "";



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Uniformizefunction fizzbuzz(){ return array_map( function ($i) {

$formatted = "";

if ($i % 3 === 0) { $formatted .= "Fizz"; } if ($i % 5 === 0) { $formatted .= "Buzz"; } if ($formatted === "") { $formatted .= "$i"; }


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Scalar vector→function fizzbuzz(){ return array_map( function ($i) {

$formatted = "";

if ($i % 3 === 0) { $formatted .= "Fizz"; } if ($i % 5 === 0) { $formatted .= "Buzz"; } if ($formatted === "") { $formatted .= "$i"; }


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Scalar vector→function fizzbuzz(){ return array_map( function ($i) {

$formatted = array();

if ($i % 3 === 0) { $formatted[] = "Fizz"; } if ($i % 5 === 0) { $formatted[] = "Buzz"; } if (count($formatted) === 0) { $formatted[] = "$i"; }

return implode($formatted); }, range(1, 100) );}

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Extract conditionfunction fizzbuzz(){ return array_map( function ($i) {

$formatted = array();

if ($i % 3 === 0) { $formatted[] = "Fizz"; } if ($i % 5 === 0) { $formatted[] = "Buzz"; } if (count($formatted) === 0) { $formatted[] = "$i"; }


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Extract conditionfunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $condition = $i % 3 === 0; if ($condition) { $formatted[] = "Fizz"; } $condition = $i % 5 === 0; if ($condition) { $formatted[] = "Buzz"; } $condition = count($formatted) === 0; if ($condition) { $formatted[] = "$i"; } return implode($formatted); }, range(1, 100) );}

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Extract representationfunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $condition = $i % 3 === 0; if ($condition) { $formatted[] = "Fizz"; } $condition = $i % 5 === 0; if ($condition) { $formatted[] = "Buzz"; } $condition = count($formatted) === 0; if ($condition) { $formatted[] = "$i"; } return implode($formatted); }, range(1, 100) );}

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Extract representationfunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $condition = $i % 3 === 0; $representation = "Fizz"; if ($condition) $formatted[] = $representation;

$condition = $i % 5 === 0; $representation = "Buzz"; if ($condition) $formatted[] = $representation;

$condition = count($formatted) === 0; $representation = "$i"; if ($condition) $formatted[] = $representation;


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Eliminate duplicationfunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $condition = $i % 3 === 0; $representation = "Fizz"; if ($condition) $formatted[] = $representation;




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Eliminate duplicationfunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $condition = $i % 3 === 0; $representation = "Fizz"; if ($condition) $formatted[] = $representation;




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Eliminate duplicationfunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $rules = array(array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"));

foreach ($rules as $rule) { list($condition, $representation) = $rule; if ($condition) $formatted[] = $representation; }



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array_filter($array, $callable)function fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $rules = array(array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"));




array_filter(array(1, 2, 3, 4), function ($x) { return $x > 2; });

// array(3, 4)

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Eliminate conditionalfunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $rules = array(array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"));




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Eliminate conditionalfunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $rules = array_filter( array(array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz")), function (array $rule) { return $rule[0]; }); foreach ($rules as $rule) { list($condition, $representation) = $rule; $formatted[] = $representation; } $condition = count($formatted) === 0; $representation = "$i"; if ($condition) $formatted[] = $representation;


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Remove some noisefunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $rules = array_filter( array(array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz")), function (array $rule) { return $rule[0]; }); foreach ($rules as $rule) { list($condition, $representation) = $rule; $formatted[] = $representation; } $condition = count($formatted) === 0; $representation = "$i"; if ($condition) $formatted[] = $representation;


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Remove some noisefunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $rules = array_filter( array(array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz")), function (array $rule) { return $rule[0]; }); foreach ($rules as $rule) {

$formatted[] = $rule[1]; } $condition = count($formatted) === 0; $representation = "$i"; if ($condition) $formatted[] = $representation;


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Remove some noisefunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $rules = array_filter( array(array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz")), function (array $rule) { return $rule[0]; }); foreach ($rules as $rule) {



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Zoom infunction fizzbuzz(){ return array_map( function ($i) { $formatted = array(); $rules = array_filter( array(array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz")), function (array $rule) { return $rule[0]; }); foreach ($rules as $rule) {



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Zoom in$formatted = array();$rules = array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; });

foreach ($rules as $rule) { $formatted[] = $rule[1];}

$condition = count($formatted) === 0;$representation = "$i";if ($condition) { $formatted[] = $representation;}

return implode($formatted);

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$formatted $rules→$formatted = array();$rules = array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; });


$condition = count($formatted) === 0;$representation = "$i";if ($condition) { $formatted[] = $representation;}


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$condition = count($rules) === 0;$representation = "$i";if ($condition) { $formatted[] = $representation;}


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Uniformize$formatted = array();$rules = array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; });


$condition = count($rules) === 0;$representation = "$i";if ($condition) { $formatted[] = $representation;}


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Uniformize$formatted = array();$rules = array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; });


$rule = array(count($rules) === 0, "$i");

if ($rule[0]) { $formatted[] = $rule[1];}


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$rule = array(count($rules) === 0, "$i");

if ($rule[0]) { $formatted[] = $rule[1];}


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if (count($rules) === 0) { $rules[] = array(count($rules) === 0, "$i");}


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Remove some redundancy$formatted = array();$rules = array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; });




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Remove some redundancy$formatted = array();$rules = array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; });

if (count($rules) === 0) { $rules[] = array(true, "$i");}



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array_pad($array, $size, $value)$formatted = array();$rules = array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; });




array_pad(array(1, 2), 5, 42); // array(1, 2, 42, 42, 42)

array_pad(array(1, 2), 1, 42); // array(1, 2)

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array_pad(array(1, 2), 5, 42); // array(1, 2, 42, 42, 42)

array_pad(array(1, 2), 1, 42); // array(1, 2)

Padding$formatted = array();$rules = array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; });




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Padding$formatted = array();$rules = array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; });




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Padding$formatted = array();$rules = array_pad(array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i"));



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Padding$formatted = array();$rules = array_pad( array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i"));



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foreach array_map()→$formatted = array();$rules = array_pad( array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i"));



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foreach array_map()→$formatted = array_map(function(array $rule){return $rule[1];}, array_pad( array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i")));


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foreach array_map→$formatted = array_map( function (array $rule) { return $rule[1]; }, array_pad( array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i") ));


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inline implode$formatted = array_map( function (array $rule) { return $rule[1]; }, array_pad( array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i") ));


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inline implodereturn implode(array_map( function (array $rule) { return $rule[1]; }, array_pad( array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i") )));

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inline implodereturn implode( array_map( function (array $rule) { return $rule[1]; }, array_pad( array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i") ) ));

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Eliminate unneeded valuesreturn implode( array_map( function (array $rule) { return $rule[1]; }, array_pad( array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i") ) ));

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array_pad() array_map()↔return implode( array_map( function (array $rule) { return $rule[1]; }, array_pad( array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), 1, array(true, "$i") ) ));

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array_pad() array_map()↔return implode( array_pad( array_map( function (array $rule) { return $rule[1]; }, array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ) ), 1, "$i" ));

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array_map() for_all()→return implode( array_pad( array_map( function (array $rule) { return $rule[1]; }, array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ) ), 1, "$i" ));

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array_map() for_all()→

return implode( array_pad( array_map( function (array $rule) { return $rule[1]; }, array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ) ), 1, "$i" ));

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array_map() for_all()→function for_all(array $items, $action){ return array_map($action, $items);}

return implode( array_pad( for_all(

array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), function (array $rule) { return $rule[1]; } ), 1, "$i" ));

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array_filter matching_rules→function for_all(array $items, $action){ return array_map($action, $items);}


array_filter( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), ), function (array $rule) { return $rule[0]; } ), function (array $rule) { return $rule[1]; } ), 1, "$i" ));

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array_filter matching_rules→function matching_rules(array $rules) { return array_filter( $rules, function (array $rule) { return $rule[0]; }); }


matching_rules( array( array($i % 3 === 0, "Fizz"), array($i % 5 === 0, "Buzz"), )

), function (array $rule) { return $rule[1]; } ), 1, "$i" ));

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For all matching rules...function matching_rules(array $rules) { return array_filter( $rules, function (array $rule) { return $rule[0]; }); }




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select representation




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select representation$select_representation = function (array $rule) { return $rule[1]; };



), $select_representation ), 1, "$i" ));

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select representationfunction select_representation(){ return function (array $rule) { return $rule[1]; };}



), select_representation() ), 1, "$i" ));

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array_pad() either_or_else()→function select_representation(){ return function (array $rule) { return $rule[1]; };}



), select_representation() ), 1, "$i" ));

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array_pad() either_or_else()→function either_or_else(array $either, $or_else){ return array_pad($either, 1, $or_else);}

return implode( either_or_else( for_all(


), select_representation() ),

"$i" ));

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implode() concat()→function either_or_else(array $either, $or_else){ return array_pad($either, 1, $or_else);}

return implode( either_or_else( for_all(



"$i" ));

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implode() concat()→function concat(array $parts){ return implode($parts);}

return concat( either_or_else( for_all(



"$i" ));

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Parametric rules: conditionsfunction concat(array $parts){ return implode($parts);}




"$i" ));

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Parametric rules: conditionsfunction matching_rules(array $rules) { return array_filter( $rules, function (array $rule) { return $rule[0]; }); }




"$i" ));

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Parametric rules: conditionsfunction matching_rules($n, array $rules) { return array_filter( $rules, function (array $rule) use ($n) {return $rule[0]($n);});}

return concat( either_or_else( for_all( matching_rules( $i, array( array(function ($n) { return $n%3 === 0; }, "Fizz"), array(function ($n) { return $n%5 === 0; }, "Buzz"), ) ), select_representation() ), "$i" ));

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Remove duplicationfunction matching_rules($n, array $rules) { return array_filter( $rules, function (array $rule) use ($n) {return $rule[0]($n);});}

return concat( either_or_else( for_all( matching_rules( $i, array( array(function ($n) { return $n%3 === 0; }, "Fizz"), array(function ($n) { return $n%5 === 0; }, "Buzz"), ) ), select_representation() ), "$i" ));

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Remove duplicationfunction is_multiple_of($divisor) { return function ($n) use ($divisor) { return $n % $divisor === 0; };}

return concat( either_or_else( for_all( matching_rules( $i, array( array(is_multiple_of(3), "Fizz"), array(is_multiple_of(5), "Buzz"), ) ), select_representation() ), "$i" ));

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Parametric representationfunction is_multiple_of($divisor) { return function ($n) use ($divisor) { return $n % $divisor === 0; };}

return concat( either_or_else( for_all( matching_rules( $i, array( array(is_multiple_of(3), "Fizz"), array(is_multiple_of(5), "Buzz"), ) ), select_representation() ), "$i" ));

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Parametric representation

return concat( either_or_else( for_all( matching_rules( $i, array( array(is_multiple_of(3), function ($n) { return "Fizz"; }), array(is_multiple_of(5), function ($n) { return "Buzz"; }), ) ), select_representation() ), function ($n) { return "$n"; } ));

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return concat(for_all( either_or_else( for_all( matching_rules( $i, array( array(is_multiple_of(3), function ($n) { return "Fizz"; }), array(is_multiple_of(5), function ($n) { return "Buzz"; }), ) ), select_representation() ), function ($n) { return "$n"; } ), function ($f) use ($i) { return $f($i); }));

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return concat( for_all( either_or_else( for_all( matching_rules( $i, array(array(is_multiple_of(3), function ($n){return "Fizz";}), array(is_multiple_of(5), function ($n){return "Buzz";}),) ), select_representation() ), function ($n) { return "$n"; } ), function ($f) use ($i) { return $f($i); } ));

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Parametric actionfunction select_representation() { return function (array $rule) { return $rule[1]; };}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(array(is_multiple_of(3), function ($n){return "Fizz";}), array(is_multiple_of(5), function ($n){return "Buzz";}),) ), select_representation() ), function ($n) { return "$n"; } ), function ($f) use ($i) { return $f($i); } ));

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Parametric actionfunction select_action() { return function (array $rule) { return $rule[1]; };}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(array(is_multiple_of(3), function ($n){return "Fizz";}), array(is_multiple_of(5), function ($n){return "Buzz";}),) ), select_action() ), function ($n) { return "$n"; } ), function ($f) use ($i) { return $f($i); } ));

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Parametric actionfunction select_action() { return function (array $rule) { return $rule[1]; };}


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Parametric action


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Parametric actionfunction apply_with($n) { return function ($f) use ($n) { return $f($n); };}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(array(is_multiple_of(3), function ($n){return "Fizz";}), array(is_multiple_of(5), function ($n){return "Buzz";}),) ), select_action() ), function ($n) { return "$n"; } ), apply_with($i) ));

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Parametric actionfunction apply_with($n) { return function ($f) use ($n) { return $f($n); };}


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Remove duplication


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Remove duplicationfunction const_fn($const) { return function ($n) use ($const) { return $const; };}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(array(is_multiple_of(3), const_fn("Fizz")), array(is_multiple_of(5), const_fn("Buzz")),) ), select_action() ), function ($n) { return "$n"; } ), apply_with($i) ));

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Name thingsfunction const_fn($const) { return function ($n) use ($const) { return $const; };}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(array(is_multiple_of(3), const_fn("Fizz")), array(is_multiple_of(5), const_fn("Buzz")),) ), select_action() ), function ($n) { return "$n"; } ), apply_with($i) ));

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Name thingsfunction to_string() { return function ($n) { return "$n"; };}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(array(is_multiple_of(3), const_fn("Fizz")), array(is_multiple_of(5), const_fn("Buzz")),) ), select_action() ), to_string() ), apply_with($i) ));

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Encapsulationfunction to_string() { return function ($n) { return "$n"; };}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(array(is_multiple_of(3), const_fn("Fizz")), array(is_multiple_of(5), const_fn("Buzz")),) ), select_action() ), to_string() ), apply_with($i) ));

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Encapsulationfunction when($condition, $action) { return array($condition, $action);}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(when( is_multiple_of(3), const_fn("Fizz")), when( is_multiple_of(5), const_fn("Buzz")),) ), select_action() ), to_string() ), apply_with($i) ));

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When ... then ...function when($condition, $action) { return array($condition, $action);}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(when( is_multiple_of(3), const_fn("Fizz")), when( is_multiple_of(5), const_fn("Buzz")),) ), select_action() ), to_string() ), apply_with($i) ));

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When ... then ...function then($action) { return $action;}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(when( is_multiple_of(3), then(const_fn("Fizz"))), when( is_multiple_of(5), then(const_fn("Buzz"))),) ), select_action() ), to_string() ), apply_with($i) ));

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Extract ugly detailsfunction then($action) { return $action;}

return concat( for_all( either_or_else( for_all( matching_rules( $i, array(when( is_multiple_of(3), then(const_fn("Fizz"))), when( is_multiple_of(5), then(const_fn("Buzz"))),) ), select_action() ), to_string() ), apply_with($i) ));

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Extract ugly detailsfunction apply_rules($n, array $rules, $otherwise_fn){ return concat( for_all( either_or_else( for_all(matching_rules($n, $rules), select_action()), $otherwise_fn ), apply_with($n) ) );}

return apply_rules( $i, array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), to_string());

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Extract ugly detailsfunction apply_rules($n, array $rules, $otherwise_fn){ return concat( for_all( either_or_else( for_all(matching_rules($n, $rules), select_action()), $otherwise_fn ), apply_with($n) ) );}

return apply_rules( $i, array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), to_string());

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Extract ugly details

function fizzbuzz(){ return for_all( range(1, 100), function ($i) { apply_rules( $i, array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), to_string() ) } );}

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Extract ugly details

function fizzbuzz(){ return for_all( range(1, 100), function ($i) { apply_rules( $i, array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), to_string() ) } );}

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Extract ugly detailsfunction apply_rules(array $rules, $otherwise_fn) { return function ($n) use ($rules, $otherwise_fn) { return concat(for_all( ... )); };}function fizzbuzz(){ return for_all( range(1, 100), apply_rules(

array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), to_string() )

);}

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Readability refinementsfunction apply_rules(array $rules, $otherwise_fn) { return function ($n) use ($rules, $otherwise_fn) { return concat(for_all( ... )); };}function fizzbuzz(){ return for_all( range(1, 100), apply_rules(

array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), to_string() )

);}

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Readability refinementsfunction otherwise($action) { return $action;}

function fizzbuzz(){ return for_all( range(1, 100), apply_rules(

array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), otherwise(to_string()) )

);}

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array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), otherwise(to_string()) )

);}

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array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), otherwise(convert_to_string()) )

);}

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Extract, extract, extract


array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), ), otherwise(convert_to_string()) )

);}

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Extract, extract, extractfunction format_numbers(array $rules) { return for_all(range(1, 100), apply_rules($rules, otherwise(convert_to_string())));}function fizzbuzz(){ return

array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), )

;}

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The resulting algorithmfunction format_numbers(array $rules){ return for_all(range(1, 100), apply_rules($rules, otherwise(convert_to_string())));}function fizzbuzz(){ return array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), );}

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The resulting algorithmfunction format_numbers(array $rules){ return for_all(range(1, 100), apply_rules($rules, otherwise(convert_to_string())));}function fizzbuzz(){ return array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), );}

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The resulting algorithmfunction format_numbers(array $rules){ return for_all(range(1, 100), apply_rules($rules, otherwise(convert_to_string())));}function fizzbuzz_rules(){ return array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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The resulting algorithmfunction format_numbers(array $rules){ return for_all(range(1, 100), apply_rules($rules, otherwise(convert_to_string())));}function fizzbuzz_rules(){ return array( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))), );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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The resulting algorithmfunction format_numbers(array $rules){ return for_all(range(1, 100), apply_rules($rules, otherwise(convert_to_string())));}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}function rules(){ return func_get_args();}

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SOLID: Open/Closed Principlefunction format_numbers(array $rules){ return for_all(range(1, 100), apply_rules($rules, otherwise(convert_to_string())));}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}

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SOLID: Open/Closed Principlefunction format_numbers(array $rules){ return for_all(range(1, 100), apply_rules($rules, otherwise(convert_to_string())));}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzzbeep_rules(){ return append( fizzbuzz_rules(), when(is_multiple_of(7), then(const_fn("Beep"))) );}

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SOLID: Open/Closed Principlefunction format_numbers(array $rules){ return for_all(range(1, 100), apply_rules($rules, otherwise(convert_to_string())));}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzzbeep_rules(){ return append( fizzbuzz_rules(), when(is_multiple_of(7), then(const_fn("Beep"))) );}function append(array $array, $item) { ... }

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SOLID: What about the others?function format_numbers(array $rules){ return for_all( range(1, 100), apply_rules( $rules, otherwise(convert_to_string()) ) );}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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SOLID: Single Responsibilityfunction format_numbers(array $rules){ return for_all( range(1, 100), apply_rules( $rules, otherwise(convert_to_string()) ) );}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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SOLID: Single Responsibility ✓function format_numbers(array $rules){ return for_all( range(1, 100), apply_rules( $rules, otherwise(convert_to_string()) ) );}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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SOLID: Liskov Substitutionfunction format_numbers(array $rules){ return for_all( range(1, 100), apply_rules( $rules, otherwise(convert_to_string()) ) );}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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SOLID: Liskov Substitution ✓function format_numbers(array $rules){ return for_all( range(1, 100), apply_rules( $rules, otherwise(convert_to_string()) ) );}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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SOLID: Interface Segregationfunction format_numbers(array $rules){ return for_all( range(1, 100), apply_rules( $rules, otherwise(convert_to_string()) ) );}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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SOLID: Interface Segregation ✓function format_numbers(array $rules){ return for_all( range(1, 100), apply_rules( $rules, otherwise(convert_to_string()) ) );}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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SOLID: Dependency Inversionfunction format_numbers(array $rules){ return for_all( range(1, 100), apply_rules( $rules, otherwise(convert_to_string()) ) );}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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SOLID: Dependency Inversion ✓function format_numbers(array $rules){ return for_all( range(1, 100), apply_rules( $rules, otherwise(convert_to_string()) ) );}function fizzbuzz_rules(){ return rules( when(is_multiple_of(3), then(const_fn("Fizz"))), when(is_multiple_of(5), then(const_fn("Buzz"))) );}function fizzbuzz(){ return format_numbers(fizzbuzz_rules());}

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Wait a sec: isn't SOLID for OOP?146/149

Wait a sec: isn't SOLID for OOP?

If you have OO, you can have FP: Iterator Lazy evaluation→ Iterator, Command Map, Filter→ Command, Factory High order functions→ Immutability Composition Over Inheritance

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Get out of your comfort zone

And extend your mental toolbox!

Thank you!

Engineering

Programming in handstand