process george's comments

[msc-thesis1617.git] / methods.top.tex

diff --git a/methods.top.tex b/methods.top.tex
index 9777db5..c05165a 100644 (file)
--- a/methods.top.tex
+++ b/methods.top.tex
@@ -1,10 +1,9 @@
-\section{\acrlong{TOP}}
-\subsection{\gls{iTasks}}
+\section{iTasks}

 \gls{TOP} is a recent programming paradigm implemented as
 \gls{iTasks}\cite{achten_introduction_2015} in the pure lazy functional
 language \gls{Clean}\cite{brus_cleanlanguage_1987}. \gls{iTasks} is a
 \gls{EDSL} to model workflow tasks in the broadest sense. A \CI{Task} is just
 \gls{TOP} is a recent programming paradigm implemented as
 \gls{iTasks}\cite{achten_introduction_2015} in the pure lazy functional
 language \gls{Clean}\cite{brus_cleanlanguage_1987}. \gls{iTasks} is a
 \gls{EDSL} to model workflow tasks in the broadest sense. A \CI{Task} is just

-a function that, given some state, returns the observable \CI{TaskValue}. The
+a function that --- given some state --- returns the observable \CI{TaskValue}. The

 \CI{TaskValue} of a \CI{Task} can have different states. Not all state
 transitions are possible as shown in Figure~\ref{fig:taskvalue}. Once a value
 is stable it can never become unstable again. Stability is often reached
 \CI{TaskValue} of a \CI{Task} can have different states. Not all state
 transitions are possible as shown in Figure~\ref{fig:taskvalue}. Once a value
 is stable it can never become unstable again. Stability is often reached


@@ -20,7 +19,7 @@ image in the \CI{NoValue} state, the second image does not have all the fields
 filled in and therefore the \CI{TaskValue} remains \CI{Unstable}. In the third
 image all fields are entered and the \CI{TaskValue} transitions to the
 \CI{Unstable} state. When the user presses \emph{Continue} the value becomes
 filled in and therefore the \CI{TaskValue} remains \CI{Unstable}. In the third
 image all fields are entered and the \CI{TaskValue} transitions to the
 \CI{Unstable} state. When the user presses \emph{Continue} the value becomes

-\CI{Stable} and can not be changed any further.
+\CI{Stable} and cannot be changed any further.

 
 \begin{figure}[H]
        \centering
 
 \begin{figure}[H]
        \centering


@@ -66,5 +65,76 @@ functions that are captured in the class \CI{iTask}. Basic types have
 specialization instances for these functions and show an according interface.
 Generated interfaces can be modified with decoration operators.
 
 specialization instances for these functions and show an according interface.
 Generated interfaces can be modified with decoration operators.
 

-\subsection{Combinators}
-\todo{Stukje over combinators, in ieder geval bind en paralel}
+\section{Combinators}
+\Glspl{Task} can be combined using so called \gls{Task}-combinators.
+Combinators describe relations between \glspl{Task}. \Glspl{Task} can be
+combined in parallel, sequenced and their result values can be converted to
+\glspl{SDS}. Moreover, a very important combinator is the step combinator which
+starts a new task according to specified predicates on the \CI{TaskValue}.
+Type signatures of the basic combinators are shown in
+Listing~\ref{lst:combinators}.
+
+\begin{itemize}
+       \item Step:
+
+               The step combinator is used to start \glspl{Task} when a predicate on
+               the \CI{TaskValue} holds or an action has taken place. The bind
+               operator can be written as a step combinator.
+               \begin{lstlisting}[language=Clean]
+(>>=) infixl 1 :: (Task a) (a -> (Task b)) -> (Task b) | iTask a & iTask b
+(>>=) ta f = ta >>* [OnAction "Continue" onValue, OnValue onStable]
+    where
+        onValue (Value a _)     = Just (f a)
+        onValue _               = Nothing
+
+        onStable (Value a True) = Just (f a)
+        onStable _              = Nothing
+               \end{lstlisting}
+       \item Parallel:
+
+               The parallel combinator allows for concurrent \glspl{Task}. The
+               \glspl{Task} combined with these operators will appear at the same time
+               in the web browser of the user and the results are combined as the type
+               dictates.
+\end{itemize}
+
+\begin{lstlisting}[language=Clean,%
+       caption={\Gls{Task}-combinators},label={lst:combinators}]
+//Step combinator
+(>>*)  infixl 1 :: (Task a) [TaskCont a (Task b)] -> Task b     | iTask a & iTask b
+(>>=)  infixl 1 :: (Task a) (a -> Task b)         -> Task b   | iTask a & iTask b
+:: TaskCont a b
+       =     OnValue             ((TaskValue a)  -> Maybe b)
+       |     OnAction    Action  ((TaskValue a)  -> Maybe b)
+       | E.e: OnException         (e              -> b)       & iTask e
+       |     OnAllExceptions     (String         -> b)
+:: Action = Action String
+
+//Parallel combinators
+(-||-) infixr 3 :: (Task a) (Task a)              -> Task a     | iTask a
+(||-)  infixr 3 :: (Task a) (Task b)              -> Task b     | iTask a & iTask b
+(-||)  infixl 3 :: (Task a) (Task b)              -> Task a     | iTask a & iTask b
+(-&&-) infixr 4 :: (Task a) (Task b)              -> Task (a,b) | iTask a & iTask b
+\end{lstlisting}
+
+\section{\acrlongpl{SDS}}
+\Glspl{SDS} are an abstraction over resources that are available in the world
+or in the \gls{iTasks} system. The shared data can be a file on disk, it can be
+the time, a random integer or just some data stored in memory. The actual
+\gls{SDS} is just a record containing functions on how to read and write the
+source. In these functions the \CI{*World} is available and therefore it can
+interact with the outside world. The \CI{*IWorld} is also available and
+therefore the functions can also access other shares, possibly combining them.
+
+The basic operations for \glspl{SDS} are get, set and update. The signatures
+for these functions are shown in Listing~\ref{lst:shares}. All of the
+operations are atomic in the sense that during reading no other tasks are
+executed.
+
+\begin{lstlisting}[%
+       language=Clean,label={lst:shares},caption={\Gls{SDS} functions}]
+get ::          (ReadWriteShared r w)           -> Task r | iTask r
+set :: w        (ReadWriteShared r w)           -> Task w | iTask w
+upd :: (r -> w) (ReadWriteShared r w)           -> Task w | iTask r & iTask w
+
+\end{lstlisting}