path: root/doc/qtcreator/src/editors/creator-code-refactoring.qdoc

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/*!
    \contentspage index.html
    \page creator-editor-refactoring.html
    \previouspage creator-editor-locator.html
    \if defined(qtdesignstudio)
    \nextpage creator-editor-options.html
    \else
    \nextpage creator-beautifier.html
    \endif

    \title Refactoring

    Refactor code to:

    \list
        \li Improve internal quality of your application
        \li Improve performance and extensibility
        \li Improve code readability and maintainability
        \li Simplify code structure
    \endlist

    \if defined(qtcreator)
    \section1 Finding Symbols

    To find instances of a specific symbol in your Qt C++ project, place the
    cursor on the symbol in the editor and select \uicontrol Tools >
    \uicontrol {C++} > \uicontrol {Find References to Symbol Under Cursor} or
    press \key {Ctrl+Shift+U}.

    \note You can also select \uicontrol Edit > \uicontrol {Find/Replace} >
    \uicontrol {Advanced Find} > \uicontrol {C++ Symbols} to search for
    classes, functions, enums, and declarations either from files listed as
    part of the project or from all files that are used by the code, such as
    include files.
    \image qtcreator-search-cpp-symbols.png
    \endif

    \section1 Finding QML Types

    To find instances of a specific QML type in a project, place the cursor on
    the type and select \uicontrol Tools > \uicontrol {QML/JS} >
    \uicontrol {Find References to Symbol Under Cursor} or press
    \key {Ctrl+Shift+U}.

    \section1 Viewing Search Results

    \QC searches from the following locations:

    \list
        \li Files listed as a part of the project
        \li Files directly used by the project files (for example, generated
            files)
        \if defined(qtcreator)
        \li Header files of used frameworks and libraries
        \endif
    \endlist

    The \uicontrol {Search Results} pane shows the location
    and number of search hits in the current project.

    \if defined(qtcreator)
    \image qtcreator-refactoring-find.png
    \else
    \image qml-find-usages.png
    \endif

    You can browse the search results in the following ways:

    \list
        \li To go directly to an instance, double-click the instance in the
            \uicontrol {Search Results} pane.
        \li To move between instances, click the \inlineimage next.png
            (\uicontrol {Next Item}) button and \inlineimage prev.png
            (\uicontrol {Previous Item}) button in the
            \uicontrol {Search Results} pane.
        \li To expand and collapse the list of all instances, click the
            \inlineimage qtcreator-expand.png
            (\uicontrol {Expand All}) button.
        \li To clear the search results, click the
            \inlineimage clean_pane_small.png
            (\uicontrol Clear) button.
        \li To start a new search, click the
            \inlineimage qtcreator-new-search-icon.png
            (\uicontrol {New Search}) button.
    \endlist

    \section1 Renaming Symbols

    You can rename symbols in all files in a project.
    \if defined(qtcreator)
    When you rename a class, you can also change filenames that match the
    class name.

    To rename a specific symbol in a Qt project, place the cursor
     on it and select \uicontrol Tools > \uicontrol {C++} >
    \uicontrol {Rename Symbol Under Cursor} or press \key {Ctrl+Shift+R}.
    \endif

    To rename a QML type in a project, select \uicontrol Tools >
    \uicontrol {QML/JS} > \uicontrol {Rename Symbol Under Cursor}
    or press \key {Ctrl+Shift+R}.

    The \uicontrol {Search Results} pane shows the location
    and number of instances of the symbol in the current project.

    \if defined(qtcreator)
    \image qtcreator-refactoring-replace.png
    \else
    \image qml-rename-symbol.png
    \endif

    To replace all selected instances, enter the name of the new symbol
    in the \uicontrol {Replace with} text box, and select \uicontrol Replace.
    To omit an instance, deselect the check box next to the instance.

    \note This action replaces all selected instances of the symbol in
    all files listed in the \uicontrol {Search Results} pane. You cannot
    undo this action.

    \if defined(qtcreator)
    If the symbol is a class, select the \uicontrol {Rename files} check
    box to also change the filenames that match the class name.

    \note Renaming local symbols does not open the \uicontrol {Search Results}
    pane. The instances of the symbol are highlighted in code and you can edit
    the symbol. All instances of the local symbol are changed as you type.
    \endif

    \section1 Column Editing

    To apply a change to several rows in a column simultaneously, press
    \key Alt, select the rows, and enter or remove text. The changes are made
    simultaneously at the cursor position on all the selected rows.

    \section1 Applying Refactoring Actions

    \QC allows you to quickly and conveniently apply actions to refactor your
    code by selecting them in a context menu. The actions available depend on
    the position of the cursor in the code editor.

    \if defined(qtcreator)
    To apply refactoring actions to C++ code, right-click an operand,
    conditional statement, string, or name to open a context menu.
    \endif
    To apply refactoring actions to QML code, right-click an item ID or name.

    In the context menu, select \uicontrol {Refactoring} and then select a
    refactoring action.

    You can also press \key {Alt+Enter} to open a context menu that contains
    refactoring actions available in the current cursor position.

    \if defined(qtcreator)
    If you use the \l{Parsing C++ Files with the Clang Code Model}
    {Clang code model} to parse the C++ files, the
    \l{http://clang.llvm.org/diagnostics.html}{Clang fix-it hints}
    that have been integrated into \QC are also available to you. In addition to
    the standard ways of activating refactoring actions, you can select the
    actions that are applicable on a line in the context menu in the left margin
    of the code editor.

   \section2 Refactoring C++ Code

   You can apply the following types of refactoring actions to C++ code:

   \list
        \li Change binary operands
        \li Simplify if and while conditions (for example, move declarations out
            of if conditions)
        \li Modify strings (for example, set the encoding for a string to
            Latin-1, mark strings translatable, and convert symbol names to
            camel case)
        \li Create variable declarations
        \li Create function declarations and definitions
   \endlist

    The following table summarizes the refactoring actions for C++ code. The
    action is available when the cursor is in the position described in the
    Activation column.

    \table
        \header
            \li Refactoring Action
            \li Description
            \li Activation
        \row
            \li Add Curly Braces
            \li Adds curly braces to an if statement that does not contain a
                compound statement. For example, rewrites

    \code
    if (a)
        b;
    \endcode

                as

    \code
    if (a) {
        b;
    }
    \endcode
            \li \c if
        \row
            \li Move Declaration out of Condition
            \li Moves a declaration out of an if or while condition to simplify
                the condition. For example, rewrites

    \code
    if (Type name = foo()) {}
    \endcode

                as

    \code
    Type name = foo;
    if (name) {}
    \endcode
            \li Name of the introduced variable
        \row
            \li Rewrite Condition Using ||
            \li Rewrites the expression according to De Morgan's laws. For
                example, rewrites:
    \code
    !a && !b
    \endcode

                as

    \code
    !(a || b)
    \endcode
            \li \c &&
        \row
            \li Rewrite Using \e operator
            \li Rewrites an expression negating it and using the inverse
                operator. For example, rewrites:

            \list

    \li    \code
    a op b
    \endcode

                as

    \code
    !(a invop b)
    \endcode

    \li    \code
    (a op b)
    \endcode

                as

    \code
    !(a invop b)
    \endcode

    \li   \code
    !(a op b)
    \endcode

                as

    \code
    (a invob b)
    \endcode

    \endlist

            \li \c {<=}, \c {<}, \c {>}, \c {>=}, \c {==} or \c {!=}
        \row
            \li Split Declaration
            \li Splits a simple declaration into several declarations. For
                example, rewrites:
    \code
    int *a, b;
    \endcode

                as

    \code
    int *a;
    int b;
    \endcode
            \li Type name or variable name
        \row
            \li Split if Statement
            \li Splits an if statement into several statements. For example,
                rewrites:

    \code
    if (something && something_else) {
    }
    \endcode

                as

    \code
    if (something) {
       if (something_else) {
       }
    }
    \endcode

                and

    \code
    if (something || something_else)
        x;
    \endcode

                with

    \code
    if (something)
        x;
    else if (something_else)
        x;
    \endcode

            \li \c && or \c ||
        \row
            \li Swap Operands
            \li Rewrites an expression in the inverse order using the inverse
                operator. For example, rewrites:
    \code
    a op b
    \endcode

                as
    \code
    b flipop a
    \endcode
            \li \c {<=}, \c {<}, \c {>},  \c {>=}, \c {==}, \c {!=}, \c {&&}
                or \c {||}
        \row
            \li Convert to Decimal
            \li Converts an integer literal to decimal representation
            \li Numeric literal
        \row
            \li Convert to Hexadecimal
            \li Converts an integer literal to hexadecimal representation
            \li Numeric literal
        \row
            \li Convert to Octal
            \li Converts an integer literal to octal representation
            \li Numeric literal
        \row
            \li Convert to Objective-C String Literal
            \li Converts a string literal to an Objective-C string literal if
                the file type is Objective-C(++). For example, rewrites the
                following strings

    \code
    "abcd"
    QLatin1String("abcd")
    QLatin1Literal("abcd")
    \endcode

                as

    \code
    @"abcd"
    \endcode
            \li String literal
        \row
            \li Enclose in QLatin1Char()
            \li Sets the encoding for a character to Latin-1, unless the
                character is already enclosed in QLatin1Char, QT_TRANSLATE_NOOP,
                tr, trUtf8, QLatin1Literal, or QLatin1String. For example,
                rewrites

    \code
    'a'
    \endcode

                as

    \code
    QLatin1Char('a')
    \endcode
            \li String literal
        \row
            \li Enclose in QLatin1String()
            \li Sets the encoding for a string to Latin-1, unless the string is
                already enclosed in QLatin1Char, QT_TRANSLATE_NOOP, tr, trUtf8,
                QLatin1Literal, or QLatin1String. For example, rewrites
    \code
    "abcd"
    \endcode

                as

    \code
    QLatin1String("abcd")
    \endcode

            \li String literal

        \row
            \li Mark as Translatable
            \li Marks a string translatable. For example, rewrites \c "abcd"
                with one of the following options, depending on which of them is
                available:

    \code
    tr("abcd")
    QCoreApplication::translate("CONTEXT", "abcd")
    QT_TRANSLATE_NOOP("GLOBAL", "abcd")
    \endcode

            \li String literal

        \row
            \li Add Definition in ...
            \li Inserts a definition stub for a function declaration either in
                the header file (inside or outside the class) or in the
                implementation file. For free functions, inserts the definition
                after the declaration of the function or in the implementation
                file. Qualified names are minimized when possible, instead of
                always being fully expanded.

                For example, rewrites

    \code
    Class Foo {
        void bar();
    };
    \endcode

                as (inside class)

    \code
    Class Foo {
        void bar() {

        }
    };
    \endcode

                as (outside class)

    \code
    Class Foo {
        void bar();
    };

    void Foo::bar()
    {

    }
    \endcode

                as (in implementation file)

    \code
    // Header file
    Class Foo {
        void bar();
    };

    // Implementation file
    void Foo::bar()
    {

    }
    \endcode

            \li Function name
        \row
            \li Add \c Function Declaration
            \li Inserts the member function declaration that matches the member
                function definition into the class declaration. The function can
                be \c {public}, \c {protected}, \c {private}, \c {public slot},
                \c {protected slot}, or \c {private slot}.
            \li Function name
        \row
            \li Switch with Next/Previous Parameter
            \li Moves a parameter down or up one position in a parameter list.
            \li Parameter in the declaration or definition of a function
        \row
            \li Extract Function
            \li Moves the selected code to a new function and replaces the block
                of code with a call to the new function. Enter a name for the
                function in the \uicontrol {Extract Function Refactoring}
                dialog.
            \li Block of code selected
        \row
            \li Extract Constant as Function Parameter
            \li Replaces the selected literal and all its occurrences with the
                function parameter \c{newParameter}. The parameter
                \c{newParameter} will have the original literal as the default
                value.
            \li Block of code selected
        \row
            \li Add Local Declaration
            \li Adds the type of an assignee, if the type of the right-hand
                side of the assignment is known. For example, rewrites

    \code
    a = foo();
    \endcode

                as

    \code
    Type a = foo();
    \endcode

                where Type is the return type of \c {foo()}

            \li Assignee

        \row
            \li Convert to Camel Case
            \li Converts a symbol name to camel case, where elements of the name
                are joined without delimiter characters and the initial
                character of each element is capitalized. For example, rewrites
                \c an_example_symbol as \c anExampleSymbol and
                \c AN_EXAMPLE_SYMBOL as \c AnExampleSymbol
            \li Identifier
        \row
            \li Complete Switch Statement
            \li Adds all possible cases to a switch statement of the type
                \c enum
            \li \c switch
        \row
            \li Generate Missing Q_PROPERTY Members
            \li Adds missing members to a \c Q_PROPERTY:
            \list
                \li \c read function
                \li \c write function, if there is a WRITE
                \li \c {onChanged} signal, if there is a NOTIFY
                \li data member with the name \c {m_<propertyName>}
            \endlist
            \li \c Q_PROPERTY
        \row
            \li Apply Changes
            \li Keeps function declarations and definitions synchronized by
                checking for the matching declaration or definition when you
                edit a function signature and by applying the changes to the
                matching code.
            \li Function signature. When this action is available, a light bulb
                icon appears: \inlineimage refactormarker.png
        \row
            \li Add #include for undeclared or forward declared identifier
            \li Adds an \c {#include} directive to the current file to make the
                definition of a symbol available.
            \li Undeclared identifier
        \row
            \li Reformat Pointers or References
            \li Reformats declarations with pointers or references according
                to the code style settings for the current project. In case no
                project is open, the current global code style settings are
                used.

                For example, rewrites:

    \code
    char*s;
    \endcode

                as

    \code
    char *s;
    \endcode

                When applied to selections, all suitable declarations in the
                selection are rewritten.

            \li Declarations with pointers or references and selections
                containing such declarations
        \row
            \li Create Getter and Setter Member Functions
            \li Creates either both getter and setter member functions for
                member variables or only a getter or setter.
            \li Member variable in class definition
        \row
            \li Move Function Definition
            \li Moves a function definition to the implementation file, outside
                the class or back to its declaration. For example, rewrites:
    \code
    class Foo
    {
      void bar()
      {
          // do stuff here
      }
    };
    \endcode

                as
    \code
    class Foo
    {
      void bar();
    };

    void Foo::bar() {
        // do stuff here
    }
    \endcode

            \li Function signature
        \row
            \li Move All Function Definitions
            \li Moves all function definitions to the implementation file or
                outside the class. For example, rewrites:
    \code
    class Foo
    {
      void bar()
      {
          // do stuff here
      }
      void baz()
      {
          // do stuff here
      }
    };
    \endcode

                as

    \code
    class Foo
    {
      void bar();
      void baz();
    };

    void Foo::bar() {
        // do stuff here
    }

    void Foo::baz() {
        // do stuff here
    }
    \endcode

            \li Class name
        \row
            \li Assign to Local Variable
            \li Adds a local variable which stores the return value of a
                function call or a new expression. For example, rewrites:

    \code
    QString s;
    s.toLatin1();
    \endcode

                as

    \code
    QString s;
    QByteArray latin1 = s.toLatin1();
    \endcode

                and

    \code
    new Foo;
    \endcode

                as

    \code
    Foo * localFoo = new Foo;
    \endcode

            \li Function call or class name
        \row
            \li Insert (Pure) Virtual Functions
            \li Select an insertion mode:
            \list
                \li Insert only declarations.
                \li Insert declarations and the corresponding definitions inside the class.
                \li Insert declarations and the corresponding definitions outside the class.
                \li Insert declarations and the corresponding definitions in the implementation file
                (only if an implementation file exists).
            \endlist
            \image qtcreator-refactoring-virtual-function-dialog.png

            \li Class or base class name
        \row
            \li Optimize for-Loop
            \li Rewrites post increment operators as pre increment operators and
                post decrement operators as pre decrement operators. It also
                moves other than string or numeric literals and id expressions
                from the condition of a for loop to its initializer. For
                example, rewrites:

    \code
    for (int i = 0; i < 3 * 2; i++)
    \endcode

                as

    \code
    for (int i = 0, total = 3 * 2; i < total; ++i)
    \endcode
            \li \c for

        \row
            \li Escape String Literal as UTF-8
            \li Escapes non-ASCII characters in a string literal to hexadecimal
                escape sequences. String Literals are handled as UTF-8.
            \li String literal

        \row
            \li Unescape String Literal as UTF-8
            \li Unescapes octal or hexadecimal escape sequences in a string
                literal. String Literals are handled as UTF-8.
            \li String literal

        \row
            \li Convert to Stack Variable
            \li Converts the selected pointer to a stack variable. For example,
                rewrites:

    \code
    QByteArray *foo = new QByteArray("foo");
    foo->append("bar");
    \endcode

                as

    \code
    QByteArray foo("foo");
    foo.append("bar");
    \endcode

                This operation is limited to work only within function scope.
                Also, the coding style for pointers and references is not
                respected yet.
            \li Pointer Variable

        \row
            \li Convert to Pointer
            \li Converts the selected stack variable to a pointer. For example,
                rewrites:

    \code
    QByteArray foo = "foo";
    foo.append("bar");
    \endcode

                as

    \code
    QByteArray *foo = new QByteArray("foo");
    foo->append("bar");
    \endcode

                This operation is limited to work only within function scope.
                Also, the coding style for pointers and references is not
                respected yet.
            \li Stack Variable
        \row
            \li Convert connect() to Qt 5 Style
            \li Converts a Qt 4 QObject::connect() to Qt 5 style.
            \li QObject::connect() (Qt 4 style)
    \endtable
    \endif

    \section2 Refactoring QML Code

    You can apply the following types of refactoring actions to QML code:

    \list
        \li Rename IDs
        \li Split initializers
        \li Move a QML type into a separate file to reuse it in other .qml files
    \endlist

    The following table summarizes the refactoring actions for QML code. The
    action is available when the cursor is in the position described in the
    Activation column.

    \table
        \header
            \li Refactoring Action
            \li Description
            \li Activation

        \row
            \li Move Component into Separate File
            \li Moves a QML type into a separate file. Give the new component a
                name and select whether properties are set for the new component
                or for the original one.

                \image qtcreator-move-component-into-separate-file.png

            \li QML type name. This action is also available in the
                \uicontrol {Form Editor} in the Design mode.
        \row
            \li Split Initializer
            \li Reformats a one-line type into a multi-line type. For example,
                rewrites

    \code
    Item { x: 10; y: 20; width: 10 }
    \endcode

                as

    \code
    Item {
        x: 10;
        y: 20;
        width: 10
    }
    \endcode

            \li QML type property
        \row
            \li Wrap Component in Loader
            \li Wraps the type in a Component type and loads it dynamically in a
                Loader type. This is usually done to improve startup time.
            \li QML type name
        \row
            \li Add a message suppression comment
            \li Prepends the line with an annotation comment that stops the
                message from being generated.
            \li Error, warning or hint from static analysis

    \endtable
   */