X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/2562c82329113d43b0de122c86ac23f0dca0e669..a75124d0da255513e83d2e62f963dd849829466b:/docs/latex/wx/variant.tex diff --git a/docs/latex/wx/variant.tex b/docs/latex/wx/variant.tex index a6cd0b1a1c..5ede86d940 100644 --- a/docs/latex/wx/variant.tex +++ b/docs/latex/wx/variant.tex @@ -14,7 +14,7 @@ The {\bf wxVariant} class represents a container for any type. A variant's value can be changed at run time, possibly to a different type of value. -As standard, wxVariant can store values of type bool, char, double, long, string, +As standard, wxVariant can store values of type bool, wxChar, double, long, string, string list, time, date, void pointer, list of strings, and list of variants. However, an application can extend wxVariant's capabilities by deriving from the class \helpref{wxVariantData}{wxvariantdata} and using the wxVariantData form of @@ -23,7 +23,7 @@ Actual values for user-defined types will need to be accessed via the wxVariantD object, unlike the case for basic data types where convenience functions such as \helpref{GetLong}{wxvariantgetlong} can be used. -Pointers to any \helpref{wxObject}{helpref} derived class can also easily be stored +Pointers to any \helpref{wxObject}{wxobject} derived class can also easily be stored in a wxVariant. wxVariant will then use wxWidgets' built-in RTTI system to set the type name (returned by \helpref{GetType}{wxvariantgettype}) and to perform type-safety checks at runtime. @@ -31,10 +31,57 @@ type-safety checks at runtime. This class is useful for reducing the programming for certain tasks, such as an editor for different data types, or a remote procedure call protocol. -An optional name member is associated with a wxVariant. This might be used, for example, in CORBA -or OLE automation classes, where named parameters are required. - -Note that as of wxWidgets 2.7.1, wxVariant is reference counted. +An optional name member is associated with a wxVariant. This might be used, for example, +in CORBA or OLE automation classes, where named parameters are required. + +Note that as of wxWidgets 2.7.1, wxVariant is \helpref{reference counted}{trefcount}. +Additionally, the convenience macros {\bf DECLARE\_VARIANT\_OBJECT} and +{\bf IMPLEMENT\_VARIANT\_OBJECT} were added so that adding (limited) support +for conversion to and from wxVariant can be very easily implemented without modifying +either wxVariant or the class to be stored by wxVariant. Since assignment operators +cannot be declared outside the class, the shift left operators are used like this: + +\begin{verbatim} + // in the header file + DECLARE_VARIANT_OBJECT(MyClass) + + // in the implementation file + IMPLEMENT_VARIANT_OBJECT(MyClass) + + // in the user code + wxVariant variant; + MyClass value; + variant << value; + + // or + value << variant; +\end{verbatim} + +For this to work, MyClass must derive from \helpref{wxObject}{wxobject}, implement +the \helpref{wxWidgets RTTI system}{runtimeclassoverview} +and support the assignment operator and equality operator for itself. Ideally, it +should also be reference counted to make copying operations cheap and fast. This +can be most easily implemented using the reference counting support offered by +\helpref{wxObject}{wxobject} itself. By default, wxWidgets already implements +the shift operator conversion for a few of its drawing related classes: + +\begin{verbatim} +IMPLEMENT_VARIANT_OBJECT(wxColour) +IMPLEMENT_VARIANT_OBJECT(wxImage) +IMPLEMENT_VARIANT_OBJECT(wxIcon) +IMPLEMENT_VARIANT_OBJECT(wxBitmap) +\end{verbatim} + +Note that as of wxWidgets 2.9.0, wxVariantData no longer inherits from wxObject +and wxVariant no longer uses the type-unsafe wxList class for list +operations but the type-safe wxVariantList class. Also, wxVariantData now +supports the Clone function for implementing the \helpref{wxVariant::Unshare}{wxvariantunshare} function. +Clone is implemented automatically by IMPLEMENT\_VARIANT\_OBJECT. + +Since wxVariantData no longer derives from wxObject, any code that tests the type +of the data using wxDynamicCast will require adjustment. You can use the macro +wxDynamicCastVariantData with the same arguments as wxDynamicCast, to use C++ RTTI +type information instead of wxWidgets RTTI. \wxheading{Derived from} @@ -44,6 +91,10 @@ Note that as of wxWidgets 2.7.1, wxVariant is reference counted. +\wxheading{Library} + +\helpref{wxBase}{librarieslist} + \wxheading{See also} \helpref{wxVariantData}{wxvariantdata} @@ -58,15 +109,15 @@ Default constructor. \func{}{wxVariant}{\param{const wxVariant\& }{variant}} -Copy constructor. +Copy constructor, uses \helpref{reference counting}{trefcount}. -\func{}{wxVariant}{\param{const char*}{ value}, \param{const wxString\& }{name = ``"}} +\func{}{wxVariant}{\param{const wxChar*}{ value}, \param{const wxString\& }{name = ``"}} \func{}{wxVariant}{\param{const wxString\&}{ value}, \param{const wxString\& }{name = ``"}} Construction from a string value. -\func{}{wxVariant}{\param{char}{ value}, \param{const wxString\& }{name = ``"}} +\func{}{wxVariant}{\param{wxChar}{ value}, \param{const wxString\& }{name = ``"}} Construction from a character value. @@ -83,7 +134,7 @@ Construction from a boolean value. Construction from a double-precision floating point value. -\func{}{wxVariant}{\param{const wxList\&}{ value}, \param{const wxString\& }{name = ``"}} +\func{}{wxVariant}{\param{const wxVariantList\&}{ value}, \param{const wxString\& }{name = ``"}} Construction from a list of wxVariant objects. This constructor copies {\it value}, the application is still responsible for @@ -111,15 +162,15 @@ Construction from an array of strings. This constructor copies {\it value} and \func{}{wxVariant}{\param{DATE\_STRUCT*}{ val}, \param{const wxString\& }{name = ``"}} -Construction from a odbc date value. Represented internally by a \helpref{wxDateTime}{wxdatetime} value. +Construction from a ODBC date value. Represented internally by a \helpref{wxDateTime}{wxdatetime} value. \func{}{wxVariant}{\param{TIME\_STRUCT*}{ val}, \param{const wxString\& }{name = ``"}} -Construction from a odbc time value. Represented internally by a \helpref{wxDateTime}{wxdatetime} value. +Construction from a ODBC time value. Represented internally by a \helpref{wxDateTime}{wxdatetime} value. \func{}{wxVariant}{\param{TIMESTAMP\_STRUCT*}{ val}, \param{const wxString\& }{name = ``"}} -Construction from a odbc timestamp value. Represented internally by a \helpref{wxDateTime}{wxdatetime} value. +Construction from a ODBC timestamp value. Represented internally by a \helpref{wxDateTime}{wxdatetime} value. \membersection{wxVariant::\destruct{wxVariant}}\label{wxvariantdtor} @@ -129,6 +180,7 @@ Destructor. Note that destructor is protected, so wxVariantData cannot usually be deleted. Instead, \helpref{DecRef}{wxvariantdatadecref} should be called. +See \helpref{reference-counted object destruction}{refcountdestruct} for more info. \membersection{wxVariant::Append}\label{wxvariantappend} @@ -161,7 +213,7 @@ Deletes the contents of the list. \constfunc{bool}{Convert}{\param{wxString*}{ value}} -\constfunc{bool}{Convert}{\param{char*}{ value}} +\constfunc{bool}{Convert}{\param{wxChar*}{ value}} \constfunc{bool}{Convert}{\param{wxDateTime*}{ value}} @@ -194,7 +246,7 @@ Returns the boolean value. \membersection{wxVariant::GetChar}\label{wxvariantgetchar} -\constfunc{char}{GetChar}{\void} +\constfunc{wxChar}{GetChar}{\void} Returns the character value. @@ -219,6 +271,13 @@ Returns the date value. Returns the floating point value. +\membersection{wxVariant::GetList}\label{wxvariantgetlist} + +\constfunc{wxVariantList &}{GetList}{\void} + +Returns a reference to the wxVariantList class used by +wxVariant if this wxVariant is currently a list of variants. + \membersection{wxVariant::GetLong}\label{wxvariantgetlong} \constfunc{long}{GetLong}{\void} @@ -241,7 +300,7 @@ Gets the string value. \constfunc{wxString}{GetType}{\void} -Returns the value type as a string. The built-in types are: bool, char, date, double, list, long, string, stringlist, time, void*. +Returns the value type as a string. The built-in types are: bool, char, datetime, double, list, long, string, arrstring, void*. If the variant is null, the value type returned is the string ``null" (not the empty string). @@ -312,6 +371,15 @@ is of type list, but the number of elements in the list is zero. Sets the internal variant data, deleting the existing data if there is any. +\membersection{wxVariant::Unshare}\label{wxvariantunshare} + +\func{bool}{Unshare}{\void} + +Makes sure that any data associated with this variant is not shared with other +variants. For this to work, \helpref{wxVariantData::Clone}{wxvariantdataclone} must +be implemented for the data types you are working with. Clone is implemented +for all the default data types. + \membersection{wxVariant::operator $=$}\label{wxvariantassignment} \func{void}{operator $=$}{\param{const wxVariant\& }{value}} @@ -320,9 +388,9 @@ Sets the internal variant data, deleting the existing data if there is any. \func{void}{operator $=$}{\param{const wxString\& }{value}} -\func{void}{operator $=$}{\param{const char* }{value}} +\func{void}{operator $=$}{\param{const wxChar* }{value}} -\func{void}{operator $=$}{\param{char }{value}} +\func{void}{operator $=$}{\param{wxChar }{value}} \func{void}{operator $=$}{\param{const long }{value}} @@ -334,7 +402,7 @@ Sets the internal variant data, deleting the existing data if there is any. \func{void}{operator $=$}{\param{wxObject* }{value}} -\func{void}{operator $=$}{\param{const wxList\& }{value}} +\func{void}{operator $=$}{\param{const wxVariantList\& }{value}} \func{void}{operator $=$}{\param{const wxDateTime\& }{value}} @@ -346,7 +414,7 @@ Sets the internal variant data, deleting the existing data if there is any. \func{void}{operator $=$}{\param{const TIMESTAMP\_STRUCT* }{value}} -Assignment operators. +Assignment operators, using \helpref{reference counting}{trefcount} when possible. \membersection{wxVariant::operator $==$}\label{wxvarianteq} @@ -354,9 +422,9 @@ Assignment operators. \constfunc{bool}{operator $==$}{\param{const wxString\& }{value}} -\constfunc{bool}{operator $==$}{\param{const char* }{value}} +\constfunc{bool}{operator $==$}{\param{const wxChar* }{value}} -\constfunc{bool}{operator $==$}{\param{char }{value}} +\constfunc{bool}{operator $==$}{\param{wxChar }{value}} \constfunc{bool}{operator $==$}{\param{const long }{value}} @@ -368,7 +436,7 @@ Assignment operators. \constfunc{bool}{operator $==$}{\param{wxObject* }{value}} -\constfunc{bool}{operator $==$}{\param{const wxList\& }{value}} +\constfunc{bool}{operator $==$}{\param{const wxVariantList\& }{value}} \constfunc{bool}{operator $==$}{\param{const wxArrayString\& }{value}} @@ -382,9 +450,9 @@ Equality test operators. \constfunc{bool}{operator $!=$}{\param{const wxString\& }{value}} -\constfunc{bool}{operator $!=$}{\param{const char* }{value}} +\constfunc{bool}{operator $!=$}{\param{const wxChar* }{value}} -\constfunc{bool}{operator $!=$}{\param{char }{value}} +\constfunc{bool}{operator $!=$}{\param{wxChar }{value}} \constfunc{bool}{operator $!=$}{\param{const long }{value}} @@ -396,7 +464,7 @@ Equality test operators. \constfunc{bool}{operator $!=$}{\param{wxObject* }{value}} -\constfunc{bool}{operator $!=$}{\param{const wxList\& }{value}} +\constfunc{bool}{operator $!=$}{\param{const wxVariantList\& }{value}} \constfunc{bool}{operator $!=$}{\param{const wxArrayString\& }{value}} @@ -415,11 +483,11 @@ Returns the value at {\it idx} (zero-based). Returns a reference to the value at {\it idx} (zero-based). This can be used to change the value at this index. -\membersection{wxVariant::operator char}\label{wxvariantchar} +\membersection{wxVariant::operator wxChar}\label{wxvariantchar} -\constfunc{char}{operator char}{\void} +\constfunc{char}{operator wxChar}{\void} -Operator for implicit conversion to a char, using \helpref{wxVariant::GetChar}{wxvariantgetchar}. +Operator for implicit conversion to a wxChar, using \helpref{wxVariant::GetChar}{wxvariantgetchar}. \membersection{wxVariant::operator double}\label{wxvariantdouble} @@ -449,13 +517,18 @@ Operator for implicit conversion to a pointer to a void, using \helpref{wxVarian Operator for implicit conversion to a pointer to a \helpref{wxDateTime}{wxdatetime}, using \helpref{wxVariant::GetDateTime}{wxvariantgetdatetime}. + + +%% wxVariantData + + \section{\class{wxVariantData}}\label{wxvariantdata} -The {\bf wxVariantData} is used to implement a new type for wxVariant. Derive from wxVariantData, -and override the pure virtual functions. +The {\bf wxVariantData} class is used to implement a new type for \helpref{wxVariant}{wxvariant}. +Derive from wxVariantData, and override the pure virtual functions. -wxVariantData is reference counted, but you don't normally have to care about this, as -wxVariant manages the count automatically. However, incase your application needs to take +wxVariantData is \helpref{reference counted}{refcount}, but you don't normally have to care about this, +as wxVariant manages the count automatically. However, in case your application needs to take ownership of wxVariantData, be aware that the object is created with reference count of 1, and passing it to wxVariant will not increase this. In other words, \helpref{IncRef}{wxvariantdataincref} needs to be called only if you both take ownership of wxVariantData and pass it to a wxVariant. @@ -463,13 +536,17 @@ Also note that the destructor is protected, so you can never explicitly delete a instance. Instead, \helpref{DecRef}{wxvariantdatadecref} will delete the object automatically when the reference count reaches zero. +\wxheading{Include files} + + + \wxheading{Derived from} -\helpref{wxObject}{wxobject} +No base class -\wxheading{Include files} +\wxheading{Library} - +\helpref{wxBase}{librarieslist} \wxheading{See also} @@ -483,6 +560,14 @@ when the reference count reaches zero. Default constructor. +\membersection{wxVariantData::Clone}\label{wxvariantdataclone} + +\constfunc{wxVariantData*}{Clone}{\void} + +This function can be overridden to clone the data. +Implement Clone if you wish \helpref{wxVariant::Unshare}{wxvariantunshare} to work +for your data. This function is implemented for all built-in data types. + \membersection{wxVariantData::DecRef}\label{wxvariantdatadecref} \func{void}{DecRef}{\void} @@ -491,7 +576,8 @@ Decreases reference count. If the count reaches zero, the object is automatically deleted. Note that destructor of wxVariantData is protected, so delete -cannot be used as normal. Instead, DecRef should be called. +cannot be used as normal. Instead, \helpref{DecRef}{wxvariantdatadecref} should be called. + \membersection{wxVariantData::Eq}\label{wxvariantdataeq} @@ -548,3 +634,4 @@ the data is of this type (the check is done during the run-time) or \helpref{RTTI overview}{runtimeclassoverview}\\ \helpref{wxDynamicCast}{wxdynamiccast} +