Smell your Code! @ Free Dimension

Smell your Code!

Yaser Sulaiman

www.free-dimension.com 1

These slides are based on an
internal presentation I gave
@ Free Dimension (FD)


It contained examples from real
projects


FD agreed to publish it online under
a CC BY-NC-SA license…


after removing, or disguising, the
real examples


Disguised examples are marked
with

δ www.free-dimension.com 6

Our road map


What? Why? How?


If you can take away only 1 lesson…


Don’t Repeat Yourself!


This rule is so important I have to
break it


Don’t Repeat Yourself!


What? Why? How?


Code smells?!


Warning signs


photo by pj_in_oz

Surface indications of deeper
problems


photo by BenChenowethWork

Surface indications of deeper
problems


What? Why? How?


The bigger picture


Software
Quality

Code Quality

Code Smells

not to scale

Writing HQ code should be the
priority


One path to cleaner code goes
through code smells


What? Why? How?


Can you smell code?!


photo by lanceball


There’re many code smells


The following smells are just a
subset


They’re some of the smells I smelled
while working here


Code Smell #1


DupIicated code DupIicated code

The nastiest code smell


Example #1


BooksController
&
NotebooksController


The diff test


FD Employees Only!

ignoring whitespace differences

Example #2


MessagesController


class MessagesController extends AppController {
function zebra_inbox() {
// inbox code
}

function zebra_view($id = null) {
// view message code
}
}


// inbox code
}

function elephant_inbox() {
// inbox code
}

}

function elephant_view($id = null) {
}
}


But then came the penguin, the
dolphin, the chimp,…


Refactor!


$this->setAction('inbox');
}

function elephant_inbox() {
$this->setAction('inbox');
}

function inbox() {
// inbox code
}

$this->setAction('view', $id);
}

function elephant_view($id = null) {
$this->setAction('view', $id);
}

function view($id = null) {
}
}


Added plus: no duplicated views


FD Employees Only!


Code Smell #2


Too many parameters


How many is too many?


Example

(brace your noses!)


public abstract class AProvider
{
public abstract void AddToFamily(int familyId, string firstName, string sex,
string photo, DateTime? birthDate, string birthCountry, string birthCity,
bool living, DateTime? deathDate, string country, string city, string email,
string homepage, string mobilePhone, string biography, string jobTitle,
string maritalStatus, string spouse, int order, int? fatherId);

public abstract void UpdateInFamily(int id, int familyId, string firstName,
string sex, string photo, DateTime? birthDate, string birthCountry,
string birthCity, bool living, DateTime? deathDate, string country,
string city, string email, string homepage, string mobilePhone,
string biography, string jobTitle, string maritalStatus, string spouse,
int order, int? fatherId);
}


!


I misunderstood coupling. My bad!


public abstract class AProvider
{
public abstract void AddToFamily(Person person);

public abstract void UpdateInFamily(Person person);
}


The remaining smells have many
examples; check the repository


Code Smell #3


Not following a coding
convention/standard/style
consistently


The specifics doesn’t really matter;
what matters most is consistency


Code Smell #4


// code.CommentOut();


“Commented-out code is an
abomination.”—Uncle Bob
photo used with permission of Uncle Bob

Don’t commit commented-out code


Code Smell #5


redundant

// This is a comment


Comments
should focus on

What? Why? How?


What? Why? How?


I may have come off as an a$$


My code smells as bad as everyone
else’s.. sometimes even worse


But I’m aware of my smells


I try my best to prevent them


I don’t ignore them; I deal with
them


I smell my code


You should smell your code too


If you want to sniff more…


more than just code smells

…</presentation>
<questions>…


Smell your Code! @ Free Dimension

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