X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=top%2Fint.tex;h=1b310cd90b7035db169097b679f187c8b417817e;hb=e36fac1dc27e8fda89f7970d4e1eb1d49d73f47f;hp=7921a9b470897e302714fb648003e07705c28cf5;hpb=a32d07a619a22edaf51648683eedef695d7fb28a;p=phd-thesis.git diff --git a/top/int.tex b/top/int.tex index 7921a9b..1b310cd 100644 --- a/top/int.tex +++ b/top/int.tex @@ -83,9 +83,9 @@ withDevice spec deviceTask = withShared newMap \sdsupdates-> withShared ([], [MTTSpecRequest], False) \channels-> withShared default \dev->parallel - [ channelSync spec - , watchForShutdown - , watchChannels + [ channelSync spec channels + , watchForShutdown channels + , watchChannelMessages dev channels , waitForSpecification >>| deviceTask >>* [ifStable: issueShutdown] @@ -117,17 +117,32 @@ liftmTask :: (Main (MTask BCInterpret a)) MTDevice -> Task a | iTask a \end{lstClean} \subsection{Implementation} -Under the hood, \cleaninline{liftmTask}: -\begin{itemize} - \item Generates a fresh task identifier for the device. - \item Compiles the task and fetches the values for the tethered \glspl{SDS}. - \item Sends the task to the device - \item Watches, in parallel: the tethered \glspl{SDS} in \gls{ITASK}, if they are updated, a message is sent to the device; the \gls{SDS} update queue, if there is a downstream update, the \gls{ITASK} \gls{SDS} it references is updated as well; and the task value. -\end{itemize} - -The task value of the \cleaninline{liftmTask} task is the task value of the task on the edge device. - -\todo{v.b.\ voor liftmtask} +\Cref{lst:liftmTask_pseudo} shows the pseudocode for the \cleaninline{liftmTask} implementation +The first argument is the task and the second argument is the device which is just an \gls{ADT} containing the \glspl{SDS} referring to the device information, the \gls{SDS} update queue, and the channels. +First a fresh identifier for the task is generated using the device state. +With this identifier, the cleanup hook can be installed. +This is done to assure the task is removed from the edge device if the \gls{ITASK} task coordinating it is destroyed. +Tasks can be destroyed when for example a task executed in parallel and the parallel combinator terminates or when the condition to step holds in a sequential task combination. +Then the \gls{MTASK} compiler is invoked, its only argument besides the task is a function doing something with the results of the compilation, i.e.\ the lifted \glspl{SDS} and the messages containing the compiled and serialised task. +With the result of the compilation, the task can be executed. +First the messages are put in the channels, sending them to the device. +Then, in parallel: +\begin{enumerate*} + \item the value is watched by looking in the device state \gls{SDS}, this task also determines the task value of the whole task + \item the downstream \glspl{SDS} are monitored, i.e.\ the \cleaninline{sdsupdates} \gls{SDS} is monitored and updates from the device are applied to the associated \gls{ITASK} \gls{SDS} + \item the upstroam \glspl{SDS} are monitored by spawning tasks that watch these \glspl{SDS}, if one is updated, the novel value is sent to the edge device. +\end{enumerate*} + +\begin{lstClean}[label={lst:liftmTask_pseudo},caption={Pseudocode implementation for \texttt{liftmTask}.}] +liftmTask task (MTDevice dev sdsupdates channels) + = freshTaskId dev + >>= \tid->withCleanupHook (sendmessage [MTTTaskDel tid] channels) ( + compile task \mrefs msgs-> + sendMessage msgs channels + >>| waitForReturnAndValue tid dev + -|| watchSharesDownstream mrefs tid sdsupdates + -|| watchSharesUpstream mrefs channels tid) +\end{lstClean} \section{Lifting \texorpdfstring{\gls{ITASK}}{iTask} \texorpdfstring{\glsxtrlongpl{SDS}}{shared data sources}}\label{sec:liftsds} Lifting \gls{ITASK} \glspl{SDS} to \gls{MTASK} \glspl{SDS} is something that mostly happens at the compiler level using the \cleaninline{liftsds} function (see \cref{lst:mtask_itasksds}). @@ -143,6 +158,30 @@ class liftsds v where -> Main (MTask v u) | RWShared sds \end{lstClean} +As an example, \cref{lst:mtask_liftsds_ex} shows a lightswitch function producing an \gls{ITASK}\slash\gls{MTASK} task. +Given an \cleaninline{MTDevice} type, a device handle, an \gls{ITASK} \gls{SDS} of the type boolean is created. +This boolean represents the state of the light. +The \gls{MTASK} task uses this \gls{SDS} to turn on or off the light. +An \gls{ITASK} task that runs in parallel allows interactive updating of this state. + +\todo{dit voorbeeld aanhouden of alleen die grote gebruiken} +\begin{lstClean}[label={lst:mtask_liftsds_ex},caption={Interactive light switch program.}] +lightswitch dev = + withShared False \sh-> + liftmTask (mtask sh) dev + -|| updateSharedInformation [] sh + <<@ Hint "Light switch" +where + mtask sh = + declarePin D13 PMOutput \d13-> + liftsds \ls=sh + In fun \f=(\st-> + getSds ls + >>*. [IfValue ((!=.)st) (\v->writeD d13 v)] + >>|. f (Not st)) + In {main=f true} +\end{lstClean} + \subsection{Implementation} The compilation of the code and the serialisation of the data throws away all typing information. \Glspl{SDS} are stored in the compiler state as a map from identifiers to either an initial value or an \cleaninline{MTLens}. @@ -180,8 +219,6 @@ This identifier is then used to provide a reference to the \cleaninline{def} def }\end{lstClean} % VimTeX: SynIgnore off -\todo{v.b.\ voor lifted sdss} - \section{Home automation} This section presents a interactive home automation program (\Cref{lst:example_home_automation}) to illustrate \gls{MTASK}'s integration with \gls{ITASK}. It consists of a web interface for the user to control which tasks may be executed on either of two connected devices: an \gls{ARDUINO} UNO, connected via a serial port; and an ESP8266 based prototyping board called NodeMCU, connected via \gls{TCP} over WiFi. @@ -205,7 +242,7 @@ Using the helper function \cleaninline{mkTask}, the actual task is selected from For example, when selecting the \cleaninline{temperature} task, the current temperature is shown to the user (\cref{fig:example_screenshots3}). This task just sends a simple temperature monitoring task to the device using \cleaninline{liftmTask} and provides a view on its task value using the \cleaninline{>\&>}\footnotemark{} \gls{ITASK} combinator. \footnotetext{\cleaninline{(>\&>) infixl 1 :: (Task a) ((SDSLens () (? a) ()) -> Task b) -> Task b \| iTask a \& iTask b}} -The light switch task at \crefrange{lst:example:ls1}{lst:example:ls2} is a task that has bidirectional interaction. +The light switch task at \crefrange{lst:example:ls1}{lst:example:ls2} is a task that has bidirectional interaction using the definition of \cleaninline{lightswitch} shown in \cref{lst:mtask_liftsds_ex}. Using \cleaninline{liftsds}, the status of the light switch is synchronised with the user. The task on the edge device continuously monitors the value of the lifted \gls{SDS}. If it is different from the current state, the new value is written to the digital \gls{GPIO} pin 13 and the monitoring function is recursively called. @@ -232,8 +269,8 @@ If it is different from the current state, the new value is written to the digit \end{figure} \begin{figure} - \cleaninputlisting[firstline=12,lastline=60,numbers=left,belowskip=0pt,escapeinside={/*}{*/}]{lst/example.icl} - \begin{lstClean}[numbers=left,firstnumber=50,aboveskip=0pt,caption={An example of a home automation program.},label={lst:example_home_automation}] + \cleaninputlisting[firstline=12,lastline=50,numbers=left,belowskip=0pt,escapeinside={/*}{*/}]{lst/example.icl} + \begin{lstClean}[numbers=left,firstnumber=40,aboveskip=0pt,caption={An example of a home automation program.},label={lst:example_home_automation}] , ...][+\label{lst:example:tasks2}+]\end{lstClean} \end{figure}