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> You may find yourself writing code that refers to
variables and functions in base classes. This is
particularly true if your derived class is a refinement
or specialisation of code in your base class.
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> Instead of using the literal name of the base class in your
code, you should be using the special name
<VAR
CLASS="literal"
>parent</VAR
>, which refers to the name of your
base class as given in the <VAR
CLASS="literal"
>extends</VAR
>
declaration of your class. By doing this, you avoid using the
name of your base class in more than one place. Should
your inheritance tree change during implementation, the
change is easily made by simply changing the
<VAR
CLASS="literal"
>extends</VAR
> declaration of your class.
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<font color="#0000BB"><?php<br /></font><font color="#007700">class </font><font color="#0000BB">A </font><font color="#007700">{<br /> function </font><font color="#0000BB">example</font><font color="#007700">() {<br /> echo </font><font color="#DD0000">"I am A::example() and provide basic functionality.<br />\n"</font><font color="#007700">;<br /> }<br />}<br /><br />class </font><font color="#0000BB">B </font><font color="#007700">extends </font><font color="#0000BB">A </font><font color="#007700">{<br /> function </font><font color="#0000BB">example</font><font color="#007700">() {<br /> echo </font><font color="#DD0000">"I am B::example() and provide additional functionality.<br />\n"</font><font color="#007700">;<br /> </font><font color="#0000BB">parent</font><font color="#007700">::</font><font color="#0000BB">example</font><font color="#007700">();<br /> }<br />}<br /><br /></font><font color="#0000BB">$b </font><font color="#007700">= new </font><font color="#0000BB">B</font><font color="#007700">;<br /><br /></font><font color="#FF8000">// This will call B::example(), which will in turn call A::example().<br /></font><font color="#0000BB">$b</font><font color="#007700">-></font><font color="#0000BB">example</font><font color="#007700">();<br /></font><font color="#0000BB">?></font>
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