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\part{Instantiate Application Object Refactoring}
This is a refactoring. It is informed by some experience, but is by no means complete.
\section{Intent}
Remove coupling with global state to make application reusable in different contexts.
\section{Motivation}
\begin{itemize}
\item Allows for subclassing applications, which benefits testing
\item Provides for multiple, differently-configured applications, desirable for virtual hosting environments
\item Aesthetics, ease of understanding
\end{itemize}
\section{Mechanics}
Presuming you are working on an app named "flarg":
\begin{itemize}
\item If there is a global \texttt{\$flarg} variable which is an instance of some kind of driver, rename it to \texttt{\$flarg\_driver}
\item In \texttt{lib/base.php}, create a global \texttt{\$flarg} which is an instance of \texttt{Flarg::}
\item For each static method in \texttt{Flarg::}
\begin{itemize}
\item Find all calls of the method and replace \texttt{Flarg::method()} with \texttt{\$flarg->method()}. (\textbf{Possible exception:} if the method is truly static, meaning it will always produce the same output given the same parameters, you might want to keep it static.)
\end{itemize}
\item For each global variable (\texttt{\$flarg\_driver} is used as an example):
\begin{itemize}
\item Add a \texttt{getDriver()} method to \texttt{Flarg::}
\item Make \texttt{getDriver()} return the global variable's value
\item Find references to the global variable, and replace each with a call to \texttt{\$flarg->getDriver()}
\item When all references are replaced, do \textbf{one} of the following:
\begin{itemize}
\item Move initialization code for the value into the method
\item Introduce a field, move initialization code into constructor
\item Introduce a field which defaults to \texttt{null}, move initialization code into getter, but only execute when the field is \texttt{null} (Note, beware of introducing cycles.)
\end{itemize}
\end{itemize}
\end{itemize}
When application class gets too heavy to work with, you can use ExtractClass and/or MoveMethod to split up responsibilities.
Ideally, we will eventually end up with an application object which takes all configuration as constructor parameters, does all of the application's work (probably most via delegation - FacadePattern), but does not contain any UI code. Ideal for use from command-line scripts and unit tests.
\section{TODO}
\begin{itemize}
\item Open discussion from Horde developers
\item Check for core developer support for this pattern.
\item When/how to write tests and run tests for this refactoring?
\item "Motivation" section needs some work.
\item ...
\end{itemize}
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