Policies/Kdelibs Coding Style/cs: Difference between revisions

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<languages />
This document describes the recommended coding style for kdelibs. Nobody is forced to use this style, but to have consistent formatting of the source code files it is recommended to make use of it.
This document describes the recommended coding style for kdelibs. Nobody is forced to use this style, but to have consistent formatting of the source code files it is recommended to make use of it.


'''In short: Kdelibs coding style follows the Qt 4 coding style.'''
'''In short: Kdelibs coding style follows the [http://wiki.qt.io/Qt_Coding_Style Qt coding style], with one main difference: using curly braces even when the body of a conditional statement contains only one line.'''


== Odsazení ==
== Odsazení ==
Line 13: Line 14:
* Take useful names. No short names, except:
* Take useful names. No short names, except:
** Single character variable names can denote counters and temporary variables whose purpose is obvious
** Single character variable names can denote counters and temporary variables whose purpose is obvious
** Variables and functions start with a lowercase letter
* Variables and functions start with a lowercase letter


Example:
Příklad:
<syntaxhighlight lang="cpp-qt">
<syntaxhighlight lang="cpp-qt">
// wrong
// špatně
KProgressBar *prbar;
KProgressBar *prbar;
QString prtxt, errstr;
QString prtxt, errstr;


// correct
// správně
KProgressBar *downloadProgressBar;
KProgressBar *downloadProgressBar;
QString progressText;
QString progressText;
QString errorString;
QString errorString;
</syntaxhighlight>
</syntaxhighlight>


== Whitespace ==
== Whitespace ==
Line 34: Line 36:
* No space after a cast
* No space after a cast


Example:
Příklad:
<syntaxhighlight lang="cpp-qt">
<syntaxhighlight lang="cpp-qt">
// wrong
// špatně
QString* myString;
QString* myString;
if(true){
if(true){
}
}


// correct
// správně
QString *myString;
QString *myString;
if (true) {
if (true) {
Line 50: Line 52:
As a base rule, the left curly brace goes on the same line as the start of the statement.
As a base rule, the left curly brace goes on the same line as the start of the statement.


Example:
Příklad:
<syntaxhighlight lang="cpp-qt">
<syntaxhighlight lang="cpp-qt">
// wrong
// špatně
if (true)
if (true)
{
{
}
}


// correct
// správně
if (true) {
if (true) {
}
}
Line 64: Line 66:
Exception: Function implementations, class, struct and namespace declarations always have the opening brace on the start of a line.
Exception: Function implementations, class, struct and namespace declarations always have the opening brace on the start of a line.


Example:
Příklad:
<syntaxhighlight lang="cpp-qt">
<syntaxhighlight lang="cpp-qt">
void debug(int i)
void debug(int i)
Line 78: Line 80:
Use curly braces even when the body of a conditional statement contains only one line.
Use curly braces even when the body of a conditional statement contains only one line.


Example:
Příklad:
<syntaxhighlight lang="cpp-qt">
<syntaxhighlight lang="cpp-qt">
// wrong
// špatně
if (true)
if (true)
     return true;
     return true;
Line 87: Line 89:
     qDebug("%i", i);
     qDebug("%i", i);


// correct
// správně
if (true) {
if (true) {
     return true;
     return true;
Line 121: Line 123:
* If you add #includes for Qt classes, use both the module and class name.  This allows library code to be used by applications without excessive compiler include paths.
* If you add #includes for Qt classes, use both the module and class name.  This allows library code to be used by applications without excessive compiler include paths.


Example:
Příklad:
<syntaxhighlight lang="cpp-qt">
<syntaxhighlight lang="cpp-qt">
// wrong
// špatně
#include <QString>
#include <QString>


// correct
// správně
#include <QtCore/QString>
#include <QtCore/QString>
</syntaxhighlight>
</syntaxhighlight>
Line 134: Line 136:
<syntaxhighlight lang="text">
<syntaxhighlight lang="text">
astyle --indent=spaces=4 --brackets=linux \
astyle --indent=spaces=4 --brackets=linux \
       --indent-labels --pad-oper --unpad-paren \
       --indent-labels --pad=oper --unpad=paren \
       --one-line=keep-statements --convert-tabs \
       --one-line=keep-statements --convert-tabs \
       --indent-preprocessor \
       --indent-preprocessor \
       `find -type f -name '*.cpp'` `find -type f -name '*.cc'` `find -type f -name '*.h'`
       `find -type f -name '*.cpp'-or -name '*.cc' -or -name '*.h'`
</syntaxhighlight>
</syntaxhighlight>


With astyle (>=2.01) you need to run the following command:
Při použití astyle (>=2.01) musíte spustit následující příkaz:
<syntaxhighlight lang="text">
<syntaxhighlight lang="text">
astyle --indent=spaces=4 --brackets=linux \
astyle --indent=spaces=4 --brackets=linux \
       --indent-labels --pad-oper --unpad-paren \
       --indent-labels --pad-oper --unpad-paren --pad-header \
       --keep-one-line-statements --convert-tabs \
       --keep-one-line-statements --convert-tabs \
       --indent-preprocessor \
       --indent-preprocessor \
       `find -type f -name '*.cpp'` `find -type f -name '*.cc'` `find -type f -name '*.h'`
       `find -type f -name '*.cpp' -or -name '*.cc' -or -name '*.h'`
</syntaxhighlight>
</syntaxhighlight>


A related shell script could be found for unix in [http://websvn.kde.org/*checkout*/trunk/KDE/kdesdk/scripts/astyle-kdelibs kdesdk/scripts/astyle-kdelibs] and for windows in [http://websvn.kde.org/*checkout*/trunk/KDE/kdesdk/scripts/astyle-kdelibs.bat kdesdk/scripts/astyle-kdelibs.bat].
Note: With more recent astyle --brackets has become --style, so change --brackets=linux to --style=linux.
 
You can find a shell script to run this command in:
 
* [https://projects.kde.org/projects/kde/kdesdk/kde-dev-scripts/repository/revisions/master/raw/astyle-kdelibs kde-dev-scripts/astyle-kdelibs] (POSIX)
* [https://projects.kde.org/projects/kde/kdesdk/kde-dev-scripts/repository/revisions/master/raw/astyle-kdelibs.bat kde-dev-scripts/astyle-kdelibs.bat] (Windows)


== Emacs and Vim scripts ==
== Emacs and Vim scripts ==
The "scripts" directory in the kdesdk module contains, among other useful things, some useful additions to the Emacs and Vim text editors that make it easier to edit KDE code with them.
The [https://projects.kde.org/projects/kde/kdesdk/kde-dev-scripts/repository/revisions/master/show kde-dev-scripts] directory in the kdesdk module contains, among other useful things, some useful additions to the Emacs and Vim text editors that make it easier to edit KDE code with them.
   
   
=== Emacs ===
=== Emacs ===
The [http://websvn.kde.org/trunk/KDE/kdesdk/scripts/kde-emacs kde-emacs] directory contains a set of key bindings, macros and general useful code. It is compatible with both GNU Emacs and XEmacs.
The [https://projects.kde.org/projects/kde/kdesdk/kde-dev-scripts/repository/revisions/master/show/kde-emacs kde-emacs] directory contains a set of key bindings, macros and general useful code. It is compatible with both GNU Emacs and XEmacs.


To start using kde-emacs, add the following to your .emacs:
To start using kde-emacs, add the following to your .emacs:
Line 169: Line 176:


=== Vim ===
=== Vim ===
You can find a vim script in [http://websvn.kde.org/*checkout*/trunk/KDE/kdesdk/scripts/kde-devel-vim.vim kdesdk/scripts/kde-devel-vim.vim] that helps you to keep the coding style correct. In addition to defaulting to the kdelibs coding style it will automatically use the correct style for Solid and kdepim code. If you want to add rules for other projects feel free to add them in the SetCodingStyle function.
You can find a vim script in [https://projects.kde.org/projects/kde/kdesdk/kde-dev-scripts/repository/revisions/master/raw/kde-devel-vim.vim kde-devel-vim.vim] that helps you to keep the coding style correct. In addition to defaulting to the kdelibs coding style it will automatically use the correct style for Solid and kdepim code. If you want to add rules for other projects feel free to add them in the SetCodingStyle function.


To use the script, include it in your {{path|~/.vimrc}} like this:
To use the script, include it in your {{path|~/.vimrc}} like this:

Latest revision as of 10:25, 11 March 2016

This document describes the recommended coding style for kdelibs. Nobody is forced to use this style, but to have consistent formatting of the source code files it is recommended to make use of it.

In short: Kdelibs coding style follows the Qt coding style, with one main difference: using curly braces even when the body of a conditional statement contains only one line.

Odsazení

  • Bez tabulátorů
  • 4 mezery namísto jednoho tabulátoru

Variable declaration

  • Each variable declaration on a new line
  • Each new word in a variable name starts with a capital letter (so-called camelCase)
  • Avoid abbreviations
  • Take useful names. No short names, except:
    • Single character variable names can denote counters and temporary variables whose purpose is obvious
  • Variables and functions start with a lowercase letter

Příklad:

// špatně
KProgressBar *prbar;
QString prtxt, errstr;

// správně
KProgressBar *downloadProgressBar;
QString progressText;
QString errorString;


Whitespace

  • Use blank lines to group statements
  • Use only one empty line
  • Use one space after each keyword
  • For pointers or references, use a single space before '*' or '&', but not after
  • No space after a cast

Příklad:

// špatně
QString* myString;
if(true){
}

// správně
QString *myString;
if (true) {
}

Braces

As a base rule, the left curly brace goes on the same line as the start of the statement.

Příklad:

// špatně
if (true)
{
}

// správně
if (true) {
}

Exception: Function implementations, class, struct and namespace declarations always have the opening brace on the start of a line.

Příklad:

void debug(int i)
{
    qDebug("foo: %i", i);
}

class Debug
{
};

Use curly braces even when the body of a conditional statement contains only one line.

Příklad:

// špatně
if (true)
    return true;

for (int i = 0; i < 10; ++i)
    qDebug("%i", i);

// správně
if (true) {
    return true;
}

for (int i = 0; i < 10; ++i) {
    qDebug("%i", i);
}

Switch statements

Case labels are on the same column as the switch

Example:

switch (myEnum) {
case Value1:
    doSomething();
    break;
case Value2:
    doSomethingElse();
    // fall through
default:
    defaultHandling();
    break;
}

Line breaks

Try to keep lines shorter than 100 characters, inserting line breaks as necessary.

Qt Includes

  • If you add #includes for Qt classes, use both the module and class name. This allows library code to be used by applications without excessive compiler include paths.

Příklad:

// špatně
#include <QString>

// správně
#include <QtCore/QString>

Artistic Style (astyle) automatic code formatting

You can use astyle (>=1.23) to format code or to test if you have followed this document. Run the following command:

astyle --indent=spaces=4 --brackets=linux \
       --indent-labels --pad=oper --unpad=paren \
       --one-line=keep-statements --convert-tabs \
       --indent-preprocessor \
       `find -type f -name '*.cpp'-or -name '*.cc' -or -name '*.h'`

Při použití astyle (>=2.01) musíte spustit následující příkaz:

astyle --indent=spaces=4 --brackets=linux \
       --indent-labels --pad-oper --unpad-paren --pad-header \
       --keep-one-line-statements --convert-tabs \
       --indent-preprocessor \
       `find -type f -name '*.cpp' -or -name '*.cc' -or -name '*.h'`

Note: With more recent astyle --brackets has become --style, so change --brackets=linux to --style=linux.

You can find a shell script to run this command in:

Emacs and Vim scripts

The kde-dev-scripts directory in the kdesdk module contains, among other useful things, some useful additions to the Emacs and Vim text editors that make it easier to edit KDE code with them.

Emacs

The kde-emacs directory contains a set of key bindings, macros and general useful code. It is compatible with both GNU Emacs and XEmacs.

To start using kde-emacs, add the following to your .emacs:

(add-to-list 'load-path "/path/to/kde-emacs")
(require 'kde-emacs)

Many settings can be changed by editing the "kde-emacs" group via M-x customize-group.

For more information, including what the key bindings are and what additional settings you could add to your .emacs, please check kde-emacs.el itself.

Vim

You can find a vim script in kde-devel-vim.vim that helps you to keep the coding style correct. In addition to defaulting to the kdelibs coding style it will automatically use the correct style for Solid and kdepim code. If you want to add rules for other projects feel free to add them in the SetCodingStyle function.

To use the script, include it in your ~/.vimrc like this:

source /path/to/kde/sources/kdesdk/scripts/kde-devel-vim.vim


Document started by Urs Wolfer. Some parts of this document have been adopted from the Qt Coding Style document posted by Zack Rusin on kde-core-devel.