Ola.  

@nigelfds  

github.com/nigelfds  

(Talk  +  Examples)  ~  1hour  

(Talk  –  Examples)  ~  30mins  

Refactoring?  

a  change  made  to  the  internal  structure  of  soFware  to  make  it  easier  to  understand  and  cheaper  

to  modify  without  changing  its  observable  behavior  

-­‐  MarLn  Fowler  

 Don't  touch  anything  that  doesn't  have  coverage.  

Otherwise,  you're  not  refactoring;  you're  just  changing  shit.  

a  change  made  to  the  internal  structure  of  soFware  to  make  it  

easier  to  understand  and  cheaper  to  modify  without  changing  its  observable  behavior  

-­‐  MarLn  Fowler  

SomeLmes    it  just  feels  

right.  

Step  1:  Measure  the  

toxicity.  

Smells  in  the  code  

CyclomaLc  Complexity  

5  to  7  is  decent  for  most  ruby  code  

Saikuro  

Assignments,  Branches,  Calls    with  Flog  

Watch  for  scores  greater  than  40  

Flog  

DuplicaLon  with  Flay  

Watch  for  scores  greater  than  30  

Flay  

Control  Couples  and  more    with  Reek  

Simulated  Polymorphism  Feature  Envy  ULlity  Methods  

LinLng  with  Dust/Nitpick  

Branch  Checks  

Common  smells    in  Ruby    

PrimiLve  Obsession  

Feature  Envy  

class Cart def price @item.price + @item.tax

end end

Meta-­‐programming  

Keep  it  simple.    Keep  it  declaraLve  

Toxicity  is  more  than  code  smells  

“The  real  problem  I  have  with  the  CK  suite  and  similar  metrics  is  that  they  only  measure  a  single  module  (or  class  in  this  case).    I  claim  that  the  quality  of  the  design  of  a  system  is  not  something  that  can  be  determined  by  looking  at  individual  classes.    It  is  conceivable  that  every  class  in  a  system  could  be  considered  reasonable  by  whatever  single-­‐class  metrics  are  being  used,  but  the  overall  design  is  considered  bad.”  

hDp://www.cs.auckland.ac.nz/~ewan/  

Ewan  Tempero:  A  Research  Agenda  

Duplicity  vs  Coupling  

DEPENDENCY  

Tangles  

Step  2:  Make  it  visible  

Treemaps  (Max  CC)  

hbp://mbostock.github.com/protovis/  

Treemaps  

Dependency  matrix  

Step  3:  Agree  on  the  fix  

Step  4:      Go  fix  it  

“I  do  believe  that  complexity  is  the  enemy.  UnKl  we  beDer  understand  complexity,  our  chances  of  building  beDer  IT  systems  is  limited.  The  first  thing  we  must  understand  about  complexity  is  that  not  all  complexity  is  equal.  And  the  complexity  on  which  most  people  focus  is  probably  the  least  complex  complexity  of  all.”  

hbp://simplearchitectures.blogspot.com/2009/03/cancer-­‐of-­‐complexity.html  

Roger  Sessions  

Gracias