-The \gls{mTask}-\gls{EDSL} is the basis on which the system is built. The
-\gls{mTask}-\gls{EDSL} was created by Koopman et al.\ to support several views
-such as an \gls{iTasks} simulation and a \gls{C}-code generator. The \gls{EDSL}
-was designed to generate a ready-to-compile \gls{TOP}-like system for
-microcontrollers such as the \gls{Arduino}~\cite{koopman_type-safe_nodate}%
+The \gls{mTask}-\gls{EDSL} is the language used in the system. The
+\gls{mTask}-\gls{EDSL} was created by Koopman et al.\ and supported several
+views such as an \gls{iTasks} simulation and a \gls{C}-code generator. The
+\gls{EDSL} was designed to generate a ready-to-compile \gls{TOP}-like program
+for microcontrollers such as the \gls{Arduino}~\cite{koopman_type-safe_nodate}%
\cite{plasmeijer_shallow_2016}.
The \gls{mTask}-\gls{EDSL} is a shallowly embedded class based \gls{EDSL} and
therefore it is very suitable to have a new backend that partly implements the
classes given. The following sections show the details of the \gls{EDSL} that
-are used in this extension. The parts of the \gls{EDSL} that are not used will
+is used in this extension. The parts of the \gls{EDSL} that are not used will
not be discussed and the details of those parts can be found in the cited
literature.
A view for the \gls{mTask}-\gls{EDSL} is a type with kind \CI{*->*->*}%
\footnote{A type with two free type variables.} that implements some of the
classes given. The types do not have to be present as fields in the higher
-kinded view and can, and will most often, be exclusively phantom types. A view
-is of the form \CI{v t r}. The first type variable will be the type of the
-view. The second type variable will be the type of the \gls{EDSL}-expression
-and the third type variable represents the role of the expression. Currently
-the role of the expressions form a hierarchy. The three roles and their
-hierarchy are shown in Listing~\ref{lst:exprhier}. This implies that everything
-is a statement, only a \CI{Upd} and a \CI{Expr} are expressions. The \CI{Upd}
-restriction describes updatable expressions such as \gls{GPIO} pins and
-\glspl{SDS}.
+kinded view and can, and will most often, be exclusively phantom types. Thus,
+views are of the form: \CI{:: v t r = ...}. The first type variable will be
+the type of the view. The second type variable will be the type of the
+\gls{EDSL}-expression and the third type variable represents the role of the
+expression. Currently the role of the expressions form a hierarchy. The three
+roles and their hierarchy are shown in Listing~\ref{lst:exprhier}. This implies
+that everything is a statement, only a \CI{Upd} and a \CI{Expr} are
+expressions. The \CI{Upd} restriction describes updatable expressions such as
+\gls{GPIO} pins and \glspl{SDS}.
\begin{lstlisting}[%
label={lst:exprhier},caption={Expression role hierarchy}]
host-language value into the \gls{EDSL} domain. All standard arithmetic
functions are included in the \gls{EDSL} but are omitted in the example for
brevity. Moreover, the class restrictions are only shown in the first functions
-and omitted in subsequent funcitons. Both the boolean expression and arithmetic
-expression classes are shown in Listing~\ref{lst:arithbool}.
+and are omitted in subsequent functions. Both the boolean expression and
+arithmetic expression classes are shown in Listing~\ref{lst:arithbool}.
\begin{lstlisting}[label={lst:arithbool},
caption={Basic classes for expressions}]
The listing includes examples of implementations that illustrate this
dependency.
-The sequence operator is very straightforward and its only function is to tie
-the together in sequence.
+The sequence operator is straightforward and its only function is to tie
+two expressions together. The left expression is executed first, followed by
+the right expression.
\begin{lstlisting}[%
label={lst:control},caption={Control flow operators}]
Values can be assigned to all expressions that have an \CI{Upd} role. Examples
of such expressions are \glspl{SDS} and \gls{GPIO} pins. Moreover, class
extensions can be created for specific peripherals such as built-in
-\glspl{LED}. The classes facilitating this are shown in
+\glspl{LED}. The classes facilitating this are shown in
Listing~\ref{lst:sdsio}. In this way the assignment is the same for every
assignable entity.
\end{lstlisting}
A way of storing data in \glspl{mTask} is using \glspl{SDS}. \glspl{SDS} serve
-as variables in the \gls{mTask} and maintain their value across executions.
+as variables in \gls{mTask} and maintain their value across executions.
+\glspl{SDS} can be used by multiple \glspl{Task} and can be used to share data.
The classes associated with \glspl{SDS} are listed in
Listing~\ref{lst:sdsclass}. The \CI{Main} type is introduced to box an
-\gls{mTask} and make it recognizable by the type system.
+\gls{mTask} and make it recognizable by the type system by separating programs
+and decorations such as \glspl{SDS}.
\begin{lstlisting}[%
label={lst:sdsclass},caption={\glspl{SDS} in \gls{mTask}}]
Algorithm~\ref{lst:engine}. All the \glspl{Task} are inspected on their waiting
time. When the waiting time has not passed; the delta is subtracted and the
\gls{Task} gets pushed to the end of the queue. When the waiting has surpassed
-they are executed. When an \gls{mTask} wants to queue another \gls{mTask} it
+they are executed. When an \gls{mTask} opts to queue another \gls{mTask} it
can just append it to the queue.
+~\\
\begin{algorithm}[H]
\KwData{\textbf{queue} queue, \textbf{time} $t, t_p$}
}
}
\caption{Engine pseudocode for the \gls{C}- and
- \gls{iTasks}-backend}\label{lst:engine}
+ \gls{iTasks}-view}\label{lst:engine}
\end{algorithm}
+~\\
To achieve this in the \gls{EDSL} a \gls{Task} class is added that work in a
similar fashion as the \texttt{sds} class. This class is listed in
application that blinks a certain \gls{LED} every second. The \CI{thermostat}
expression will enable a digital pin powering a cooling fan when the analog pin
representing a temperature sensor is too high. \CI{thermostat`} shows the same
-expression but now using the assignment style \gls{GPIO} technique.
+expression but now using the assignment style \gls{GPIO} technique. The
+\CI{thermostat} example also shows that it is not necessary to run everything
+as a \CI{task}. The main program code can also just consist of the contents of
+the root \CI{main} itself.
\begin{lstlisting}[%
label={lst:exmtask},caption={Some example \glspl{mTask}}]
repositories / msc-thesis1617.git / blobdiff