Mention the Unix printing overview in the general

[wxWidgets.git] / docs / latex / wx / variant.tex

diff --git a/docs/latex/wx/variant.tex b/docs/latex/wx/variant.tex
index 951992df297d62ffea9b84c4383b1af982c590bc..0313c9316328b5be44327bed7321142f40f9c5f1 100644 (file)
--- a/docs/latex/wx/variant.tex
+++ b/docs/latex/wx/variant.tex
@@ -1,21 +1,76 @@
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Name:        variant.tex
+%% Purpose:     wxVariant docs
+%% Author:      wxWidgets Team
+%% Modified by:
+%% Created:     01/30/2005
+%% RCS-ID:      $Id$
+%% Copyright:   (c) wxWidgets Team
+%% License:     wxWindows license
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+

 \section{\class{wxVariant}}\label{wxvariant}
 
 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.
 
 \section{\class{wxVariant}}\label{wxvariant}
 
 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,
-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 the wxVariant constructor or assignment operator
-to assign this data to a variant. Actual values for user-defined types will need to be accessed
-via the wxVariantData object, unlike the case for basic data types where convenience
-functions such as GetLong can be used.
+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
+the wxVariant constructor or assignment operator to assign this data to a variant.
+Actual values for user-defined types will need to be accessed via the wxVariantData
+object, unlike the case for basic data types where convenience functions such as
+\helpref{GetLong}{wxvariantgetlong} can be used.
+
+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.

 
 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.
 
 
 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.
+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. Additionally, the
+conveniance 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 modifiying either wxVariant or the class
+to be stored by wxVariant. Since assignement 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
+    IMPLMENT_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}

 
 \wxheading{Derived from}
 
 
 \wxheading{Derived from}
 


@@ -41,13 +96,13 @@ Default constructor.
 
 Copy constructor.
 
 
 Copy constructor.
 

-\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{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.
 
 
 Construction from a character value.
 


@@ -70,12 +125,6 @@ Construction from a list of wxVariant objects. This constructor
 copies {\it value}, the application is still responsible for
 deleting {\it value} and its contents.
 
 copies {\it value}, the application is still responsible for
 deleting {\it value} and its contents.
 

-\func{}{wxVariant}{\param{const wxStringList\&}{ value}, \param{const wxString\& }{name = ``"}}
-
-Construction from a list of strings. This constructor
-copies {\it value}, the application is still responsible for
-deleting {\it value} and its contents.
-

 \func{}{wxVariant}{\param{void*}{ value}, \param{const wxString\& }{name = ``"}}
 
 Construction from a void pointer.
 \func{}{wxVariant}{\param{void*}{ value}, \param{const wxString\& }{name = ``"}}
 
 Construction from a void pointer.


@@ -86,7 +135,27 @@ Construction from a wxObject pointer.
 
 \func{}{wxVariant}{\param{wxVariantData*}{ data}, \param{const wxString\& }{name = ``"}}
 
 
 \func{}{wxVariant}{\param{wxVariantData*}{ data}, \param{const wxString\& }{name = ``"}}
 

-Construction from user-defined data. The variant holds on to the {\it data} pointer.
+Construction from user-defined data.  The variant holds onto the {\it data} pointer.
+
+\func{}{wxVariant}{\param{wxDateTime\&}{ val}, \param{const wxString\& }{name = ``"}}
+
+Construction from a \helpref{wxDateTime}{wxdatetime}.
+
+\func{}{wxVariant}{\param{wxArrayString\&}{ val}, \param{const wxString\& }{name = ``"}}
+
+Construction from an array of strings.  This constructor copies {\it value} and its contents.
+
+\func{}{wxVariant}{\param{DATE\_STRUCT*}{ val}, \param{const wxString\& }{name = ``"}}
+
+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.
+
+\func{}{wxVariant}{\param{TIMESTAMP\_STRUCT*}{ val}, \param{const wxString\& }{name = ``"}}
+
+Construction from a odbc timestamp value.  Represented internally by a \helpref{wxDateTime}{wxdatetime} value.

 
 \membersection{wxVariant::\destruct{wxVariant}}\label{wxvariantdtor}
 
 
 \membersection{wxVariant::\destruct{wxVariant}}\label{wxvariantdtor}
 


@@ -94,30 +163,65 @@ Construction from user-defined data. The variant holds on to the {\it data} poin
 
 Destructor.
 
 
 Destructor.
 

+Note that destructor is protected, so wxVariantData cannot usually
+be deleted. Instead, \helpref{DecRef}{wxvariantdatadecref} should be called.
+
+

 \membersection{wxVariant::Append}\label{wxvariantappend}
 
 \func{void}{Append}{\param{const wxVariant\&}{ value}}
 
 Appends a value to the list.
 
 \membersection{wxVariant::Append}\label{wxvariantappend}
 
 \func{void}{Append}{\param{const wxVariant\&}{ value}}
 
 Appends a value to the list.
 

+\membersection{wxVariant::Clear}\label{wxvariantclear}
+
+\func{void}{Clear}{\void}
+
+Makes the variant null by deleting the internal data and
+set the name to {\it wxEmptyString}.
+

 \membersection{wxVariant::ClearList}\label{wxvariantclearlist}
 
 \func{void}{ClearList}{\void}
 
 Deletes the contents of the list.
 
 \membersection{wxVariant::ClearList}\label{wxvariantclearlist}
 
 \func{void}{ClearList}{\void}
 
 Deletes the contents of the list.
 

+
+\membersection{wxVariant::Convert}\label{wxvariantconvert}
+
+\constfunc{bool}{Convert}{\param{long*}{ value}}
+
+\constfunc{bool}{Convert}{\param{bool*}{ value}}
+
+\constfunc{bool}{Convert}{\param{double*}{ value}}
+
+\constfunc{bool}{Convert}{\param{wxString*}{ value}}
+
+\constfunc{bool}{Convert}{\param{wxChar*}{ value}}
+
+\constfunc{bool}{Convert}{\param{wxDateTime*}{ value}}
+
+Retrieves and converts the value of this variant to the type that {\it value} is.
+
+

 \membersection{wxVariant::GetCount}\label{wxvariantgetcount}
 
 \membersection{wxVariant::GetCount}\label{wxvariantgetcount}
 

-\constfunc{int}{GetCount}{\void}
+\constfunc{size\_t}{GetCount}{\void}

 
 Returns the number of elements in the list.
 
 \membersection{wxVariant::Delete}\label{wxvariantdelete}
 
 
 Returns the number of elements in the list.
 
 \membersection{wxVariant::Delete}\label{wxvariantdelete}
 

-\func{bool}{Delete}{\param{int }{item}}
+\func{bool}{Delete}{\param{size\_t }{item}}

 
 Deletes the zero-based {\it item} from the list.
 
 
 Deletes the zero-based {\it item} from the list.
 

+\membersection{wxVariant::GetArrayString}\label{wxvariantgetarraystring}
+
+\constfunc{wxArrayString}{GetArrayString}{\void}
+
+Returns the string array value.
+

 \membersection{wxVariant::GetBool}\label{wxvariantgetbool}
 
 \constfunc{bool}{GetBool}{\void}
 \membersection{wxVariant::GetBool}\label{wxvariantgetbool}
 
 \constfunc{bool}{GetBool}{\void}


@@ -126,7 +230,7 @@ Returns the boolean value.
 
 \membersection{wxVariant::GetChar}\label{wxvariantgetchar}
 
 
 \membersection{wxVariant::GetChar}\label{wxvariantgetchar}
 

-\constfunc{char}{GetChar}{\void}
+\constfunc{wxChar}{GetChar}{\void}

 
 Returns the character value.
 
 
 Returns the character value.
 


@@ -134,7 +238,16 @@ Returns the character value.
 
 \constfunc{wxVariantData*}{GetData}{\void}
 
 
 \constfunc{wxVariantData*}{GetData}{\void}
 

-Returns a pointer to the internal variant data.
+Returns a pointer to the internal variant data. To take ownership
+of this data, you must call its \helpref{IncRef}{wxvariantdataincref}
+method. When you stop using it, \helpref{DecRef}{wxvariantdatadecref}
+must be likewise called.
+
+\membersection{wxVariant::GetDateTime}\label{wxvariantgetdatetime}
+
+\constfunc{wxDateTime}{GetDateTime}{\void}
+
+Returns the date value.

 
 \membersection{wxVariant::GetDouble}\label{wxvariantgetdouble}
 
 
 \membersection{wxVariant::GetDouble}\label{wxvariantgetdouble}
 


@@ -176,7 +289,7 @@ Gets the void pointer value.
 
 \membersection{wxVariant::GetWxObjectPtr}\label{wxvariantgetwxobjectptr}
 
 
 \membersection{wxVariant::GetWxObjectPtr}\label{wxvariantgetwxobjectptr}
 

-\constfunc{void*}{GetWxObjectPtr}{\void}
+\constfunc{wxObject*}{GetWxObjectPtr}{\void}

 
 Gets the wxObject pointer value.
 
 
 Gets the wxObject pointer value.
 


@@ -243,9 +356,9 @@ 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 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}}
 
 
 \func{void}{operator $=$}{\param{const long }{value}}
 


@@ -255,57 +368,75 @@ Sets the internal variant data, deleting the existing data if there is any.
 
 \func{void}{operator $=$}{\param{void* }{value}}
 
 
 \func{void}{operator $=$}{\param{void* }{value}}
 

+\func{void}{operator $=$}{\param{wxObject* }{value}}
+

 \func{void}{operator $=$}{\param{const wxList\& }{value}}
 
 \func{void}{operator $=$}{\param{const wxList\& }{value}}
 

-\func{void}{operator $=$}{\param{const wxStringList\& }{value}}
+\func{void}{operator $=$}{\param{const wxDateTime\& }{value}}
+
+\func{void}{operator $=$}{\param{const wxArrayString\& }{value}}
+
+\func{void}{operator $=$}{\param{const DATE\_STRUCT* }{value}}
+
+\func{void}{operator $=$}{\param{const TIME\_STRUCT* }{value}}
+
+\func{void}{operator $=$}{\param{const TIMESTAMP\_STRUCT* }{value}}

 
 Assignment operators.
 
 \membersection{wxVariant::operator $==$}\label{wxvarianteq}
 
 
 Assignment operators.
 
 \membersection{wxVariant::operator $==$}\label{wxvarianteq}
 

-\func{bool}{operator $==$}{\param{const wxVariant\& }{value}}
+\constfunc{bool}{operator $==$}{\param{const wxVariant\& }{value}}
+
+\constfunc{bool}{operator $==$}{\param{const wxString\& }{value}}

 
 

-\func{bool}{operator $==$}{\param{const wxString\& }{value}}
+\constfunc{bool}{operator $==$}{\param{const wxChar* }{value}}

 
 

-\func{bool}{operator $==$}{\param{const char* }{value}}
+\constfunc{bool}{operator $==$}{\param{wxChar }{value}}

 
 

-\func{bool}{operator $==$}{\param{char }{value}}
+\constfunc{bool}{operator $==$}{\param{const long }{value}}

 
 

-\func{bool}{operator $==$}{\param{const long }{value}}
+\constfunc{bool}{operator $==$}{\param{const bool }{value}}

 
 

-\func{bool}{operator $==$}{\param{const bool }{value}}
+\constfunc{bool}{operator $==$}{\param{const double }{value}}

 
 

-\func{bool}{operator $==$}{\param{const double }{value}}
+\constfunc{bool}{operator $==$}{\param{void* }{value}}

 
 

-\func{bool}{operator $==$}{\param{void* }{value}}
+\constfunc{bool}{operator $==$}{\param{wxObject* }{value}}

 
 

-\func{bool}{operator $==$}{\param{const wxList\& }{value}}
+\constfunc{bool}{operator $==$}{\param{const wxList\& }{value}}

 
 

-\func{bool}{operator $==$}{\param{const wxStringList\& }{value}}
+\constfunc{bool}{operator $==$}{\param{const wxArrayString\& }{value}}
+
+\constfunc{bool}{operator $==$}{\param{const wxDateTime\& }{value}}

 
 Equality test operators.
 
 \membersection{wxVariant::operator $!=$}\label{wxvariantneq}
 
 
 Equality test operators.
 
 \membersection{wxVariant::operator $!=$}\label{wxvariantneq}
 

-\func{bool}{operator $!=$}{\param{const wxVariant\& }{value}}
+\constfunc{bool}{operator $!=$}{\param{const wxVariant\& }{value}}
+
+\constfunc{bool}{operator $!=$}{\param{const wxString\& }{value}}

 
 

-\func{bool}{operator $!=$}{\param{const wxString\& }{value}}
+\constfunc{bool}{operator $!=$}{\param{const wxChar* }{value}}

 
 

-\func{bool}{operator $!=$}{\param{const char* }{value}}
+\constfunc{bool}{operator $!=$}{\param{wxChar }{value}}

 
 

-\func{bool}{operator $!=$}{\param{char }{value}}
+\constfunc{bool}{operator $!=$}{\param{const long }{value}}

 
 

-\func{bool}{operator $!=$}{\param{const long }{value}}
+\constfunc{bool}{operator $!=$}{\param{const bool }{value}}

 
 

-\func{bool}{operator $!=$}{\param{const bool }{value}}
+\constfunc{bool}{operator $!=$}{\param{const double }{value}}

 
 

-\func{bool}{operator $!=$}{\param{const double }{value}}
+\constfunc{bool}{operator $!=$}{\param{void* }{value}}

 
 

-\func{bool}{operator $!=$}{\param{void* }{value}}
+\constfunc{bool}{operator $!=$}{\param{wxObject* }{value}}

 
 

-\func{bool}{operator $!=$}{\param{const wxList\& }{value}}
+\constfunc{bool}{operator $!=$}{\param{const wxList\& }{value}}

 
 

-\func{bool}{operator $!=$}{\param{const wxStringList\& }{value}}
+\constfunc{bool}{operator $!=$}{\param{const wxArrayString\& }{value}}
+
+\constfunc{bool}{operator $!=$}{\param{const wxDateTime\& }{value}}

 
 Inequality test operators.
 
 
 Inequality test operators.
 


@@ -320,11 +451,11 @@ 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.
 
 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}
 
 
 \membersection{wxVariant::operator double}\label{wxvariantdouble}
 


@@ -348,11 +479,26 @@ Operator for implicit conversion to a string, using \helpref{wxVariant::MakeStri
 
 Operator for implicit conversion to a pointer to a void, using \helpref{wxVariant::GetVoidPtr}{wxvariantgetvoidptr}.
 
 
 Operator for implicit conversion to a pointer to a void, using \helpref{wxVariant::GetVoidPtr}{wxvariantgetvoidptr}.
 

+\membersection{wxVariant::operator wxDateTime}\label{wxvariantdatetime}
+
+\constfunc{void*}{operator wxDateTime}{\void}
+
+Operator for implicit conversion to a pointer to a \helpref{wxDateTime}{wxdatetime}, using \helpref{wxVariant::GetDateTime}{wxvariantgetdatetime}.
+

 \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.
 
 \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.
 

+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
+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.
+Also note that the destructor is protected, so you can never explicitly delete a wxVariantData
+instance. Instead, \helpref{DecRef}{wxvariantdatadecref} will delete the object automatically
+when the reference count reaches zero.
+

 \wxheading{Derived from}
 
 \helpref{wxObject}{wxobject}
 \wxheading{Derived from}
 
 \helpref{wxObject}{wxobject}


@@ -373,11 +519,15 @@ and override the pure virtual functions.
 
 Default constructor.
 
 
 Default constructor.
 

-\membersection{wxVariantData::Copy}\label{wxvariantdatacopy}
+\membersection{wxVariantData::DecRef}\label{wxvariantdatadecref}
+
+\func{void}{DecRef}{\void}

 
 

-\func{void}{Copy}{\param{wxVariantData\&}{ data}}
+Decreases reference count. If the count reaches zero, the object is
+automatically deleted.

 
 

-Copy the data from `this' object to {\it data}.
+Note that destructor of wxVariantData is protected, so delete
+cannot be used as normal. Instead, DecRef should be called.

 
 \membersection{wxVariantData::Eq}\label{wxvariantdataeq}
 
 
 \membersection{wxVariantData::Eq}\label{wxvariantdataeq}
 


@@ -398,6 +548,12 @@ Returns the string type of the data.
 If the data is a wxObject returns a pointer to the objects wxClassInfo structure, if
 the data isn't a wxObject the method returns NULL.
 
 If the data is a wxObject returns a pointer to the objects wxClassInfo structure, if
 the data isn't a wxObject the method returns NULL.
 

+\membersection{wxVariantData::IncRef}\label{wxvariantdataincref}
+
+\func{void}{IncRef}{\void}
+
+Increases reference count. Note that initially wxVariantData has reference count of 1.
+

 \membersection{wxVariantData::Read}\label{wxvariantdataread}
 
 \func{bool}{Read}{\param{ostream\&}{ stream}}
 \membersection{wxVariantData::Read}\label{wxvariantdataread}
 
 \func{bool}{Read}{\param{ostream\&}{ stream}}


@@ -421,7 +577,7 @@ Writes the data to {\it stream} or {\it string}.
 
 This macro returns the data stored in {\it variant} cast to the type {\it classname *} if
 the data is of this type (the check is done during the run-time) or
 
 This macro returns the data stored in {\it variant} cast to the type {\it classname *} if
 the data is of this type (the check is done during the run-time) or

-{\tt NULL} otherwise. 
+{\tt NULL} otherwise.

 
 
 \wxheading{See also}
 
 
 \wxheading{See also}