Difference between revisions of "Code Style"

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Revision as of 13:24, 24 July 2012

Introduction

"Every second spent enforcing code style is a waste of time". -- Someone, at some point

Status: FALSE

When I encounter really pretty code in the open-source world (and the closed-source world for that matter), I'm a lot more confident that the software has real quality. Of course, from case to case, this may actually not be true, and the style might lie to me, but the important thing is that it appears to have high quality to people. On the other hand, if I encounter code which appear to be shit (although it might really be of excellent quality), it's tempting for me to try and find some alternative. So while enforcing code style might technically be a waste of time, it's psychologically. Also, if you ever intend to use LÖVE as a reference when applying for a job (I've done that), there is a slight chance they will take a ten second look on the code. Even if they are advanced enough to evaluate the code properly, they will not be immune to good (nor bad) style.

Therefore, because I'm such a fucking drone, I'm going to refactor some code here and there (or everywhere) to make things more beautiful. And since I'm potentially fucking up everything anyway, I thought we could decide on a coding style that the majority likes. It's unlikely that we all agree on everything ... but hopefully everyone will accept the decision of the majority.

Namespaces

Namespace bodies are not indented.

 YES:
 namespace love
 {
 namespace graphics
 {
 class Foo
 {
 public:
     /* ... */
 };
 } // graphics
 } // love
 NO:
 
 namespace love
 {
     namespace graphics
     {
         class Foo
         {
         public:
             /* ... */
         };
     } // graphics
 } // love

Class declarations

Should have a capital first letter.

 YES:
 class Foo
 {
 };
 NO:
 class foo
 {
 };
 class FOO
 {
 };

Visiblity blocks should be in decreasing order.

It makes sense to have the visible "API" first. This is what a reader will normally want to know first anyway.

 YES:
 class Foo
 {
 public:
 protected:
 private:
 };
 NO:
 class Foo
 {
 private:
 protected:
 public:
 };

For multiple inheritance, each class should appear on its own line.

Each line should start with the colon or comma. My experience is that this is the most flexible style with respect to diffs and #ifdeffery.

 YES:

 class Foo : public Bar
 {
 };
 class Foo
     : public Bar
     , public Foz
 {
 };
 NO:

 class Foo : public Bar, public Foz
 {
 };

Initializer lists

Like inheritance lists, each initialization on its own line.

 YES:

 Foo::Foo()
     : bar(0)
     , foo(1)
 {
 }
 NO:
 Foo::Foo() : bar(0) , foo(1)
 {
 }

Functions/methods

Functions and methods should use camelCase.

 YES:
 
 int doomFist(int where);
 NO:
 int DoomFist(int where);
 int doom_fist(int where);

Parentheses should appear directly after the name, with no space in between.

 YES:
 int doomFist(int where);
 NO:
 int doomFist (int where);
 

There must be no unnecessary space immediately after the open-paren and immediately before the close-paren.

 YES:
 int doomFist(int where);
 NO:
 int doomFist( int where );

One-liners like getters and setters can be inlined in the class declaration. (More-than-one-liners should however not be inlined).

 RECOMMENDED:
 class Foo
 {
 public:
     void setBar(int bar) { this->bar = bar; }
     int getBar() const { return bar; }
 private:
     int bar;
 };
 DISCOURAGED:
 class Foo
 {
 public:
     void setBar(int bar);
     int getBar() const;
 private:
     int bar;
 };
 void Foo::setBar(int bar)
 {
     return this->bar = bar;
 }
 int Foo::getBar() const
 {
     return bar;
 }

Control blocks

Control blocks should have a space between the keyword the parenthesized expression. This differentiates control statements visually from function calls.

 YES:

 if (foo)
     /* ... */;
 NO:
 if(foo)
     /* ... */;

Braces should normally be omitted if they can. (Saves vertical space).

 YES:

 if (foo)
     bar();
 NO:
 if (foo)
 {
     bar();
 }
 YES:

 if (foo)
     bar();
 else
 {
     foz();
     baz();
 }
 NO:
 if (foo)
 {
     bar();
 }
 else
 {
     foz();
     baz();
 }

Braces should appear on the next line.

 YES:
 if (foo)
 {
     bar1();
     bar2();
 }
 NO:
 
 if (foo) {
     bar1();
     bar2();
 }

Pointer affinity

For pointers and references, the asterisk/ampersand should appear next to the variable name.

This makes it consistent with dereferencing (*foo), and is preferred by most LÖVE devs.

YES:

int *foo;
int &bar;
NO:

int* foo;
int& bar;

int * foo;
int & bar;
YES:

int *get_int_ptr();
int &get_int_ref();

NO:
int* get_int_ptr();
int& get_int_ref();
int * get_int_ptr();
int & get_int_ref();

Spaces vs Tabs

I personally prefer tabs, but I know I'm the only person in the world. We will probably end up with spaces, in which case I suggest 4 spaces per level.

EDIT: I was wrong, everyone (who has so far given a damn) has preferred tabs. In that case, let me specify a more advanced indentation guideline for the truly l33t, hardcore, and handsome.

MIXED TABS AND SPACES (*monocle pops*)

Use tabs for normal indentation.

I.e. when indicating scope.

 YES:
 if (foo)
 {
 <tab>bar();
 }
 NO:
 if (foo)
 {
 <space><space><space><space>bar();
 }

Use spaces for alignment.

If you really want to align stuff, then the important thing to keep in mind is that the alignment should not break if the viewer is using a tab-size that's different from yours. So, in this example, we're aligning stuff:

 if (foo)
 {
     int a_var      = 1;
     int anoter_var = 2;
     int moar       = 3;
     int doom       = 4;
 }
 YES:
 if (foo)
 {
 <tab>int a_var<space * 6>= 1;
 <tab>int anoter_var<space>= 2;
 <tab>int moar<space * 7>= 3;
 <tab>int doom<space * 7>= 4;
 }
 NO:
 if (foo)
 {
 <tab>int a_var<tab * 2>= 1;
 <tab>int anoter_var<tab>= 2;
 <tab>int moar<tab * 2>= 3;
 <tab>int doom<tab * 2>= 4;
 }

However, use alignment sparingly, because it makes a lot of diff noise when you add something that's longer than the currently longest thing, and you have to realign everything. So the best option is actually:

Documentation blocks

Asterisks should be aligned vertically.

YES:

 /**
  * Short description.
  *
  * @param foo The foo that goes in the bar.
  * @param bar The bar the foo foes into.
  */
 int foz(int foo, int& bar);

NO:

 /**
 * Short description.
 *
 * @param foo The foo that goes in the bar.
 * @param bar The bar the foo foes into.
 */
 int foz(int foo, int& bar);


If you agree to this, and you also agree that we're using tabs. You're agreeing that tabs and spaces be mixed (although in a very defined way). For a function declaration that's indented one block, you would type something like:

 <tab>/**
 <tab><space>* Short description.
 <tab><space>*
 <tab><space>* Long description
 <tab><space>*/

#includes

Non-system includes should use the double-quotes syntax.

YES:
#include "common/config.h"
NO:
#include <common/config.h>

Casts

Use C-style casts.

Remember to also Know What You Are Doing when using C-style casts.

 YES:
 Foo *foo = (Foo *) bar;
 NO:
 
 Foo *foo = (Foo*)bar;
 Foo *foo = (Foo*) bar;
 Foo *foo = (Foo *)bar;