intro/intro.tex

   1 \documentclass[../thesis.tex]{subfiles}
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   3 \input{subfilepreamble}
   4
   5 \begin{document}
   6 \chapter{Prelude}%
   7 \label{chp:introduction}
   8 \begin{chapterabstract}
   9         This chapter:
  10         \begin{itemize}
  11                 \item introduces the topic and research ventures of this dissertation;
  12                 \item shows a reading guide;
  13                 \item provides background material on the \glsxtrlong{IOT}, \glsxtrlongpl{DSL}, \glsxtrlong{TOP}, \gls{ITASK}, and \gls{MTASK}.
  14                 \item and concludes with a detailed overview of the contributions.
  15         \end{itemize}
  16 \end{chapterabstract}
  17
  18 There are at least 13.4 billion devices connected to the internet at the time of writing\footnote{\url{https://transformainsights.com/research/tam/market}, accessed on: \formatdate{13}{10}{2022}}.
  19 Each and every one of those devices senses, acts, or otherwise interacts with people, other computers, and the environment surrounding us.
  20 Even though there is a substantial variety among these devices, they have one thing in common: they are all computers to some degree and hence require software to operate.
  21
  22 An increasing amount of these connected devices are so-called \emph{edge devices} that operate in the \gls{IOT}.
  23 Typically, these edge devices are powered by microcontrollers.
  24 Said microcontrollers contain integrated circuits accommodating a microprocessor designed for use in embedded applications.
  25 Typical edge devices are therefore tiny in size; have little memory; contain a slow, but energy-efficient processor; and allow for a lot of connectivity to connect peripherals such as sensors and actuators to interact with their surroundings.
  26 %
  27 %\begin{figure}[ht]
  28 %       \centering
  29 %       \includegraphics[width=.4\linewidth]{esp}
  30 %       \caption{A typical ESP32 microcontroller prototyping board.}%
  31 %       \label{fig:esp_prototype}
  32 %\end{figure}
  33
  34 An \gls{IOT} programmer has to program each device and their interoperation using different programming paradigms, programming languages, and abstraction levels resulting in semantic friction.
  35 Programming and maintaining \gls{IOT} systems is therefore a very complex and an error-prone process.
  36
  37 This thesis describes the research carried out around taming these complex \gls{IOT} systems using \gls{TOP}.
  38 \Gls{TOP} is an innovative tierless programming paradigm for programming multi-tier interactive systems using a single declarative specification of the work that needs to be done.
  39 By utilising advanced compiler technologies, much of the internals, communication, and interoperation of the multi-tiered applications is automatically generated.
  40 The result of this compilation is a ready-for-work application.
  41 For example, the \gls{TOP} system \gls{ITASK} can be used to program all layers of a distributed web application from a single source.
  42 Unfortunately, because the abstraction level is so high, the hardware requirements are too excessive for such systems to be suitable for the average edge device.
  43
  44 This is where \glspl{DSL} are brought into play.
  45 \Glspl{DSL} are programming languages created with a specific domain in mind.
  46 Consequently, jargon does not have to be expressed in the language itself, but they can be built-in features.
  47 As a result, the hardware requirements can be drastically lower, even with high levels of abstraction.
  48
  49 To bridge the gap between the \gls{IOT} edge devices, the \gls{MTASK} \gls{DSL} is used.
  50 \Gls{MTASK} is a novel programming language for programming \gls{IOT} edge devices using \gls{TOP}.
  51 As it is integrated with \gls{ITASK}, it allows for all layers of an \gls{IOT} application to be programmed from a single source.
  52
  53 \section{Reading guide}
  54 The thesis is structured as a purely functional rhapsody.
  55 On Wikipedia, a musical rhapsody is defined as follows \citep{wikipedia_contributors_rhapsody_2022}:
  56 \begin{quote}\emph{%
  57         A \emph{rhapsody} in music is a one-movement work that is episodic yet integrated, free-flowing in structure, featuring a range of highly contrasted moods, colour, and tonality.}
  58 \end{quote}
  59 %The three episodes in this thesis are barded by the introduction and conclusion (\cref{chp:introduction,chp:conclusion}).
  60 \Cref{prt:dsl} is a paper-based---otherwise known as cumulative---episode providing insights in advanced \gls{DSL} embedding techniques for \gls{FP} languages.
  61 The chapters are readable independently.
  62 \Cref{prt:top} is a monograph showing \gls{MTASK}, a \gls{TOP} \gls{DSL} for the \gls{IOT}.
  63 Hence, the chapters are best read in order.
  64 \Cref{prt:tvt} is a journal article in which traditional tiered \gls{IOT} programming is qualitatively and quantitatively compared to tierless programming using a real-world application.
  65 The chapter is readable independently.
  66
  67 The following sections provide background material on the \gls{IOT}, \glspl{DSL}, and \gls{TOP} after which a detailed overview of the contributions is presented.
  68 Text typeset as \texttt{teletype} represents source code.
  69 Standalone source code listings are marked by the programming language used, e.g.\ \gls{CLEAN}\footnotemark, \gls{HASKELL}, \gls{CPP}, \etc.
  70 \footnotetext{\Cref{chp:clean_for_haskell_programmers} contains a guide for \gls{CLEAN} tailored to \gls{HASKELL} programmers.}
  71
  72 \section{\texorpdfstring{\Glsxtrlong{IOT}}{Internet of things}}\label{sec:back_iot}
  73 The \gls{IOT} is growing rapidly and it is changing the way people and machines interact with the world.
  74 While the term \gls{IOT} briefly gained interest around 1999 to describe the communication of \gls{RFID} devices \citep{ashton_internet_1999,ashton_that_2009}, it probably already popped up halfway the eighties in a speech by \citet{peter_t_lewis_speech_1985}:
  75
  76 \begin{quote}
  77         \emph{The \glsxtrlong{IOT}, or \glsxtrshort{IOT}, is the integration of people, processes and technology with connectable devices and sensors to enable remote monitoring, status, manipulation and evaluation of trends of such devices.}
  78 \end{quote}
  79
  80 CISCO states that the \gls{IOT} started when there where as many connected devices as there were people on the globe, i.e.\ around 2008 \citep{evans_internet_2011}.
  81 Today, \gls{IOT} is the term for a system of devices that sense the environment, act upon it and communicate with each other and the world.
  82 These connected devices are already in households all around us in the form of smart electricity meters, fridges, phones, watches, home automation, \etc.
  83
  84 When describing \gls{IOT} systems, a tiered---or layered---architecture is often used for compartmentalisation.
  85 The number of tiers heavily depends on the required complexity of the model but for the intents and purposes of this thesis, the layered architecture as shown in \cref{fig:iot-layers} is used.
  86
  87 \begin{figure}[ht]
  88         \centering
  89         \includestandalone{iot-layers}
  90         \caption{A layered \gls{IOT} architecture.}%
  91         \label{fig:iot-layers}
  92 \end{figure}
  93
  94 To explain the tiers, an example \gls{IOT} application---home automation---is dissected accordingly.
  95 Closest to the end-user is the presentation layer, it provides the interface between the user and the \gls{IOT} system.
  96 In home automation this may be a web interface or an app used on a phone or wall-mounted tablet to interact with the edge devices and view the sensor data.
  97
  98 The application layer provides the \glspl{API}, data interfaces, data processing, and data storage of the \gls{IOT} system.
  99 A cloud server or local server provides this layer in a typical home automation application.
 100
 101 The perception layer---also called edge layer---collects the data and interacts with the environment.
 102 It consists of edge devices such as microcontrollers equipped with various sensors and actuators.
 103 In home automation this layer consists of all the devices hosting the sensors and actuators such as smart light bulbs, actuators to open doors or a temperature and humidity sensors.
 104
 105 All layers are connected using the network layer.
 106 In some applications this is implemented using conventional networking techniques such as WiFi or Ethernet.
 107 However, networks or layers on top of it---tailored to the needs of the specific interconnection between layers---have been increasingly popular.
 108 Examples of this are BLE, LoRa, ZigBee, LTE-M, or \gls{MQTT} for connecting the perception layer to the application layer and techniques such as HTTP, AJAX, and WebSocket for connecting the presentation layer to the application layer.
 109
 110 Across the layers, the devices are a large heterogeneous collection of different platforms, protocols, paradigms, and programming languages often resulting in impedance problems or semantic friction between layers when programming \citep{ireland_classification_2009}.
 111 Even more so, the perception layer itself often is a heterogeneous collections of microcontrollers in itself as well, each having their own peculiarities, language of choice, and hardware interfaces.
 112 Moreover, as the edge hardware needs to be cheap, small-scale, and energy efficient, the microcontrollers used to power these devices do not have a lot of computational power, only a soup\c{c}on of memory, and little communication bandwidth.
 113 Typically the devices are unable to run a full-fledged general-purpose \gls{OS} but use compiled firmwares that are written in an imperative language.
 114 While devices are getting a bit faster, smaller, and cheaper, they keep these properties to an extent, greatly reducing the flexibility for dynamic systems where tasks are created on the fly, executed on demand, or require parallel execution.
 115 As program memory is mostly flash based and only lasts a couple of thousand writes before it wears out, it is not suitable for rapid reconfiguring and reprogramming.
 116
 117 These problems can be mitigated by dynamically sending code to be interpreted to the microcontroller.
 118 With interpretation, a specialized interpreter is flashed in the program memory once that receives the program code to execute at runtime.
 119 Interpretation always comes with an overhead, making it challenging to create them for small edge devices.
 120 However, the hardware requirements can be reduced by embedding domain-specific data into the programming language to be interpreted, so called \glspl{DSL}.
 121
 122 \section{\texorpdfstring{\Glsxtrlongpl{DSL}}{Domain-specific languages}}\label{sec:back_dsl}
 123 % General
 124 Programming languages can be divided up into two categories: \glspl{DSL}\footnote{Historically \glsxtrshortpl{DSL} have been called DSELs as well.} and \glspl{GPL} \citep{fowler_domain_2010}.
 125 Where \glspl{GPL} are not made with a demarcated area in mind, \glspl{DSL} are tailor-made for a specific domain.
 126 Writing idiomatic domain-specific code in an \gls{DSL} is easy but this may come at the cost of the \gls{DSL} being less expressive to an extent that it may not even be Turing complete.
 127 \Glspl{DSL} come in two main flavours: standalone and embedded (\cref{sec:standalone_embedded})\footnote{Standalone and embedded are also called external and internal respectively.} of which \glspl{EDSL} can further be classified into heterogeneous and homogeneous languages (\cref{sec:hetero_homo}).
 128 This hyponymy is shown in \cref{fig:hyponymy_of_dsls}.
 129
 130 \begin{figure}[ht]
 131         \centering
 132         \includestandalone{hyponymy_of_dsls}
 133         \caption{A hyponymy of \glspl{DSL} (adapted from \citet[\citepage{2}]{mernik_extensible_2013})}%
 134         \label{fig:hyponymy_of_dsls}
 135 \end{figure}
 136
 137 \subsection{Standalone and embedded}\label{sec:standalone_embedded}
 138 \glspl{DSL} where historically created as standalone languages, meaning that all machinery is developed solely for the language.
 139 The advantage of this approach is that the language designer is free to define the syntax and type system of the language as they wish, not being restricted by any constraint.
 140 Unfortunately it also means that they need to develop a compiler or interpreter for the language, making standalone \glspl{DSL} costly to create.
 141 Examples of standalone \glspl{DSL} are regular expressions, make, yacc, XML, SQL, \etc.
 142
 143 The dichotomous approach is embedding the \gls{DSL} in a host language, i.e.\ \glspl{EDSL} \citep{hudak_modular_1998}.
 144 By defining the language as constructs in the host language, much of the machinery is inherited \citep{krishnamurthi_linguistic_2001}.
 145 This greatly reduces the cost of creating embedded languages.
 146 However, there are two sides to this coin.
 147 If the syntax of the host language is not very flexible, the syntax of the \gls{DSL} may become clumsy.
 148 Furthermore, \gls{DSL} errors shown to the programmer may be larded with host language errors, making it difficult for a non-expert of the host language to work with the \gls{DSL}.
 149 \Gls{FP} languages are especially suitable for hosting embedded \glspl{DSL} because they often have strong and versatile type systems, minimal but flexible syntax and offer referential transparency.
 150
 151 \subsection{Heterogeneity and homogeneity}\label{sec:hetero_homo}
 152 \Citet{tratt_domain_2008} applied a notion from metaprogramming \citep{sheard_accomplishments_2001} to \glspl{EDSL} to define homogeneity and heterogeneity of \glspl{EDSL} as follows:
 153
 154 \begin{quote}
 155         \emph{A homogeneous system is one where all the components are specifically designed to work with each other, whereas in heterogeneous systems at least one of the components is largely, or completely, ignorant of the existence of the other parts of the system.
 156 }
 157 \end{quote}
 158
 159 Homogeneous \glspl{EDSL} are therefore languages that are solely defined as an extension to their host language.
 160 They often restrict features of the host language to provide a safer interface or capture an idiomatic pattern in the host language for reuse.
 161 The difference between a library and a homogeneous \glspl{EDSL} is not always clear.
 162 Examples of homogeneous \glspl{EDSL} are libraries such as ones for sets, regions, but also more complex tasks such as \glspl{GUI}.
 163
 164 On the other hand, heterogeneous \glspl{EDSL} are languages that are not executed in the host language.
 165 For example, \citet{elliott_compiling_2003} describe the language Pan, for which the final representation in the host language is a compiler that will, when executed, generate code for a completely different target platform.
 166 In fact, \gls{ITASK} and \gls{MTASK} are embedded \glspl{DSL}.
 167 \Gls{ITASK} runs in its host language as well so it is a homogeneous \gls{DSL}.
 168 Tasks written using \gls{MTASK} are serialised and executed on \gls{IOT} edge devices and it is therefore a heterogeneous \gls{DSL}.
 169
 170 \section{\texorpdfstring{\Glsxtrlong{TOP}}{Task-oriented programming}}\label{sec:back_top}
 171 \Gls{TOP} is a recent declarative programming paradigm for modelling interactive systems \citep{plasmeijer_task-oriented_2012}.
 172 \Citet{steenvoorden_tophat_2022} defines two instruments for \gls{TOP}: \gls{TOP} languages and \gls{TOP} engines.
 173 The language is the \emph{formal} language for specifying interactive systems.
 174 The engine is the software or hardware that executes these specifications as a ready-for-work application.
 175 In \gls{TOP} languages, tasks are the basic building blocks and they represent the actual work.
 176 Instead of dividing problems into \gls{LSOC} \gls{TOP} deals with separation of concerns in a novel way.
 177 From the data types, utilising various \emph{type-parametrised} concepts, all other aspects are handled automatically (see \cref{fig:tosd}).
 178 This approach to software development is called \gls{TOSD} \citep{wang_maintaining_2018}.
 179
 180 \begin{figure}[ht]
 181         \centering
 182         \begin{subfigure}[t]{.5\textwidth}
 183                 \centering
 184                 \includestandalone{traditional}
 185                 \caption{\Gls{LSOC} approach.}
 186         \end{subfigure}%
 187         \begin{subfigure}[t]{.5\textwidth}
 188                 \centering
 189                 \includestandalone{tosd}
 190                 \caption{\Gls{TOSD} approach.}
 191         \end{subfigure}
 192         \caption{Separation of concerns in a traditional setting compared to \gls{TOSD} (adapted from~\cite[\citepage{20}]{wang_maintaining_2018}).}%
 193         \label{fig:tosd}
 194 \end{figure}
 195
 196 \begin{description}
 197         \item[\Glsxtrshort{UI} (presentation layer):]
 198                 The \gls{UI} of the system is automatically generated from the representation of the type.
 199                 Though, practical \gls{TOP} systems allow tweaking afterwards to suit the specific needs of the application.
 200         \item[Tasks (business layer):]
 201                 A task is an abstract representation of a piece of work that needs to be done.
 202                 It provides an intuitive abstraction over work in the real world.
 203                 Tasks are observable.
 204                 During execution, it is possible to observe a---partial---result and act upon it, e.g.\ by starting new tasks
 205                 Examples of tasks are filling forms, sending emails, reading sensors or even doing physical tasks.
 206                 Just as with real-life tasks, multiple tasks can be combined in various ways such as in parallel or in sequence to form workflows.
 207                 Such combination functions are called task combinators.
 208         \item[\Glsxtrshortpl{SDS} (resource access):]
 209                 Tasks mainly communicate using their observable task values.
 210                 However, some collaboration require tasks that are not necessarily related need to share data.
 211                 \Glspl{SDS} fill this gap, they offer a safe and type safe abstraction over any data.
 212                 An \gls{SDS} can represent typed data stored in a file, a chunk of memory, a database \etc.
 213                 \Glspl{SDS} can also represent external impure data such as the time, random numbers or sensor data.
 214                 In many \gls{TOP} langauges, combinators are available to filter, combine, transform, and focus \glspl{SDS}.
 215         \item[Programming language (\glsxtrshort{UOD}):]
 216                 The \gls{UOD} is explicitly and separately modelled by the relations that exist in the functions of the host language.
 217 \end{description}
 218
 219 Applying the concepts of \gls{LSOC} to \gls{IOT} systems can broadly be done in two ways:
 220 Firstly, edge devices can be seen as simple resources, thus accessed through the resource access layer.
 221 The second view is that edge devices contain miniature \gls{LSOC} systems in itself as well.
 222 In \gls{TOSD} the same can be applied.
 223 The individual components in the miniature systems, the tasks, the \glspl{SDS}, are connected to the main system.
 224 %\todo[inline]{Is deze \P{} duidelijk genoeg?}
 225
 226 \subsection{\texorpdfstring{\Gls{ITASK}}{ITask}}
 227 The concept of \gls{TOP} originated from the \gls{ITASK} framework, a declarative interactive systems language and \gls{TOP} engine for defining multi-user distributed web applications implemented as an \gls{EDSL} in the lazy pure \gls{FP} language \gls{CLEAN} \citep{plasmeijer_itasks:_2007,plasmeijer_task-oriented_2012}.
 228 From the structural properties of the data types, the entire user interface is automatically generated.
 229 Browsers are powering \gls{ITASK}'s perception layer.
 230 The framework is written using standard web techniques such as JavaScript, HTML, and CSS, \gls{ITASK} code running in the browser relies on an interpreter that operates on \gls{CLEAN}'s intermediate language \gls{ABC} \citep{staps_lazy_2019}.
 231
 232 As an example, \cref{lst:enter_person,fig:enter_person} show the \gls{ITASK} code and the corresponding \gls{UI} for a simple task for entering information about a person and viewing the entered result after completion.
 233 From the data type definitions (\cref{lst:dt_fro,lst:dt_to}), using generic programming (\cref{lst:dt_derive}), the \glspl{UI} for the data types are automatically generated.
 234 Using task combinators (e.g.\ \cleaninline{>>!} at \cref{lst:task_comb}), the tasks can be combined in sequence.
 235 Only when the user enters a complete value in the web editor, then the continue button enables and the result can be viewed.
 236 Special combinators (e.g.\ \cleaninline{@>>} at \cref{lst:task_ui}) are used to tweak the \gls{UI} so that informative labels are displayed.
 237
 238 \begin{figure}[ht]
 239         \includegraphics[width=.325\linewidth]{person0g}
 240         \includegraphics[width=.325\linewidth]{person1g}
 241         \includegraphics[width=.325\linewidth]{person2g}
 242         \caption{The \gls{UI} for entering a person in \gls{ITASK}.}%
 243         \label{fig:enter_person}
 244 \end{figure}
 245
 246 \begin{lstClean}[numbers=left,caption={The code for entering a person in \gls{ITASK}.},label={lst:enter_person}]
 247 :: Person = { name :: String, gender :: Gender, dateOfBirth :: Date }[+\label{lst:dt_fro}+]
 248 :: Gender = Male | Female | Other String[+\label{lst:dt_to}+]
 249
 250 derive class iTask Person, Gender[+\label{lst:dt_derive}+]
 251
 252 enterPerson :: Task Person
 253 enterPerson
 254         =            Hint "Enter a person:" @>> enterInformation [][+\label{lst:task_ui}+]
 255         >>! \result->Hint "You Entered:"    @>> viewInformation  [] result[+\label{lst:task_comb}+]
 256 \end{lstClean}
 257
 258 \subsection{\texorpdfstring{\Gls{MTASK}}{MTask}}
 259 \Gls{ITASK} seems an obvious candidate at first glance for extending \gls{TOP} to \gls{IOT} edge devices.
 260 However, \gls{IOT} edge devices are in general not powerful enough to run or interpret \gls{CLEAN}\slash\gls{ABC} code, they just lack the processor speed and the memory.
 261 To bridge this gap, \gls{MTASK} was developed, a \gls{TOP} system for \gls{IOT} edge devices that is integrated in \gls{ITASK} \citep{koopman_task-based_2018}.
 262 \Gls{ITASK} abstracts away from details such as user interfaces, data storage, client-side platforms, and persistent workflows.
 263 On the other hand, \gls{MTASK} offers abstractions for edge layer-specific details such as the heterogeneity of architectures, platforms, and frameworks; peripheral access; (multi) task scheduling; and lowering energy consumption.
 264 The \gls{MTASK} language is written in \gls{CLEAN} as a multi-view \gls{EDSL} and hence there are multiple interpretations possible.
 265 The byte code compiler is the most relevant for this thesis.
 266 From an \gls{MTASK} task constructed at runtime, a compact binary representation of the work that needs to be done is compiled.
 267 This byte code is then sent to a device that running the \gls{MTASK} \gls{RTS}.
 268 This feather-light domain-specific \gls{OS} is written in portable \gls{C} with a minimal device specific interface and functions as a \gls{TOP} engine.
 269 \Gls{MTASK} is seamlessly integrated with \gls{ITASK}: \gls{MTASK} tasks are integrated in such a way that they function as \gls{ITASK} tasks, and \glspl{SDS} in on the device can tether an \gls{ITASK} \gls{SDS}.
 270 Using \gls{MTASK}, the programmer can define all layers of an \gls{IOT} system as a single declarative specification.
 271
 272 \Cref{lst:intro_blink} shows an interactive \gls{MTASK}\slash{}\gls{ITASK} application for blinking \pgls{LED} on the microcontroller every user-specified interval.
 273 \Crefrange{lst:intro:itask_fro}{lst:intro:itask_to} show the \gls{ITASK} part.
 274 First \pgls{SDS} is defined to communicate the blinking interval, then the \gls{MTASK} is connected using \cleaninline{withDevice}.
 275 Once connected, the \cleaninline{intBlink} task is sent to the device (\cref{lst:intro_liftmtask}) and, in parallel, an editor is shown that updates the value of the interval \gls{SDS} (\cref{lst:intro_editor}).
 276 The \cleaninline{intBlink} task (\crefrange{lst:intro:mtask_fro}{lst:intro:mtask_to}) is the \gls{MTASK} part of the application.
 277 It has its own tasks, \glspl{SDS}, and \gls{UOD}.
 278 This task first defines \gls{GPIO} pin 13 to be of the output type (\cref{lst:intro:declarePin}), followed by lifting the \gls{ITASK} \gls{SDS} to an \gls{MTASK} \gls{SDS} (\cref{lst:intro:liftsds}).
 279 The main expression of the program calls the \cleaninline{blink} function with an initial state.
 280 This function on \crefrange{lst:intro:blink_fro}{lst:intro:blink_to} first reads the interval \gls{SDS}, waits the specified delay, writes the state to the \gls{GPIO} pin and calls itself recursively using the inverse of the state.
 281
 282 \begin{lstClean}[numbers=left,caption={\Gls{MTASK}\slash{}\gls{ITASK} interactive blinking.},label={lst:intro_blink}]
 283 interactiveBlink :: Task Int[+\label{lst:intro:itask_fro}+]
 284 interactiveBlink =
 285         withShared 500 \iInterval->[+\label{lst:intro_withshared}+]
 286         withDevice {TCPSettings | host = ..., port = ...} \dev->
 287                     liftmTask (intBlink iInterval) dev[+\label{lst:intro_liftmtask}+]
 288                 -|| Hint "Interval (ms)" @>> updateSharedInformation [] iInterval[+\label{lst:intro_editor}+][+\label{lst:intro:itask_to}+]
 289
 290 intBlink :: Shared sds Int -> MTask v Int | mtask, liftsds v & RWShared sds[+\label{lst:intro:mtask_fro}+]
 291 intBlink iInterval =
 292            declarePin D13 PMOutput \d13->[+\label{lst:intro:declarePin}+]
 293            liftsds \mInterval=iInterval[+\label{lst:intro:liftsds}+]
 294         In fun \blink=(\st->[+\label{lst:intro:blink_fro}+]
 295                      getSds mInterval >>=. \i->delay i
 296                 >>|. writeD d13 st >>|. blink (Not st))[+\label{lst:intro:blink_to}+]
 297         In {main = blink true}[+\label{lst:intro:mtask_to}+]
 298 \end{lstClean}
 299
 300 \subsection{Other \texorpdfstring{\glsxtrshort{TOP}}{TOP} languages}
 301 While \gls{ITASK} conceived \gls{TOP}, it is not the only \gls{TOP} system.
 302 Some \gls{TOP} systems arose from Master's and Bachelor's thesis projects.
 303 For example, \textmu{}Task \citep{piers_task-oriented_2016}, a \gls{TOP} language for modelling non-interruptible embedded systems in \gls{HASKELL}, and LTasks \citep{van_gemert_task_2022}, a \gls{TOP} language written in the dynamically typed programming language {LUA}.
 304 Some \gls{TOP} languages were created to solve a practical problem.Toppyt \citep{lijnse_toppyt_2022} is a general purpose \gls{TOP} language written in \gls{PYTHON} used to host frameworks for modelling C2 systems, and hTask \citep{lubbers_htask_2022}, a vessel for experimenting with asynchronous \glspl{SDS}.
 305 Finally there are \gls{TOP} languages with strong academic foundations.
 306 \Gls{TOPHAT} is a fully formally specified \gls{TOP} language designed to capture the essence of \gls{TOP} formally \citep{steenvoorden_tophat_2019}.
 307 Such a formal specification allows for symbolic execution, hint generation, but also the translation to \gls{ITASK} for actually performing the work\citep[\citesection{G.3}]{steenvoorden_tophat_2022}.
 308
 309 \section{Contributions}\label{sec:contributions}
 310 This section provides a thorough overview of the relation to publications and the scientific contributions of the episodes and chapters.
 311
 312 \subsection{\Fullref{prt:dsl}}
 313 The \gls{MTASK} system is a heterogeneous \gls{EDSL} and during the development of it, several novel basal techniques for embedding \glspl{DSL} in \gls{FP} languages have been found.
 314 This episode is a paper based episodes on these techniques.
 315
 316 \Cref{chp:classy_deep_embedding} is based on the paper \emph{Deep Embedding with Class} \citep{lubbers_deep_2022}.
 317 While supervising \citeauthor{amazonas_cabral_de_andrade_developing_2018}'s \citeyear{amazonas_cabral_de_andrade_developing_2018} Master's thesis, focussing on an early version of \gls{MTASK}, a seed was planted for a novel deep embedding technique for \glspl{DSL} where the resulting language is extendible both in constructs and in interpretation using type classes and existential data types.
 318 Slowly the ideas organically grew to form the technique shown in the paper.
 319 The related work section is updated with the research found only after publication.
 320 \Cref{sec:classy_reprise} was added after publication and contains a (yet) unpublished extension of the embedding technique for reducing the required boilerplate at the cost of requiring some advanced type system extensions.
 321
 322 \Cref{chp:first-class_datatypes} is based on the paper \emph{First-Class Data Types in Shallow Embedded Domain-Specific Languages} \citep{lubbers_first-class_2022}.
 323 It shows how to inherit data types from the host language in \glspl{EDSL} using metaprogramming by providing a proof-of-concept implementation using \gls{HASKELL}'s metaprogramming system: \glsxtrlong{TH}.
 324 Besides showing the result, the paper also serves as a gentle introduction to using \glsxtrlong{TH} and contains a thorough literature study on research that uses \glsxtrlong{TH}.
 325 %The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer in which we discussed and refined the ideas.
 326
 327 \subsection{\nameref{prt:top}}
 328 This is a monograph compiled from the following papers and revised lecture notes on \gls{MTASK}.
 329 It provides a gentle introduction to all aspects of the \gls{MTASK} system and \gls{TOP} for the \gls{IOT}.
 330
 331 \begin{itemize}
 332         \item \emph{A Task-Based \glsxtrshort{DSL} for Microcomputers} \citep{koopman_task-based_2018}.
 333                 This is the initial \gls{TOP}\slash{}\gls{MTASK} paper.
 334                 It provides an overview of the initial \gls{TOP} \gls{MTASK} language and shows first versions of some of the interpretations.
 335         \item \emph{Task Oriented Programming for the \glsxtrlong{IOT}} \citep{lubbers_task_2018}.
 336
 337                 This paper was an extension of my Master's thesis \citep{lubbers_task_2017}.
 338                 It shows how a simple imperative variant of \gls{MTASK} was integrated with \gls{ITASK}.
 339                 While the language was a lot different from later versions, the integration mechanism is still used in \gls{MTASK} today.
 340 %               \paragraph{Contribution}
 341 %               The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer in which we discussed and refined the ideas.
 342         \item \emph{Multitasking on Microcontrollers using Task Oriented Programming} \citep{lubbers_multitasking_2019}\footnote{%
 343                 This work acknowledges the support of the ERASMUS+ project ``Focusing Education on Composability, Comprehensibility and Correctness of Working Software'', no. 2017--1--SK01--KA203--035402
 344                 }.
 345
 346                 This paper is a short paper on the multitasking capabilities of \gls{MTASK} comparing it to traditional multitasking methods for \gls{ARDUINO}.
 347 %               \paragraph{Contribution}
 348 %               The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer.
 349         \item \emph{Simulation of a Task-Based Embedded Domain Specific Language for the Internet of Things} \citep{koopman_simulation_2018}\footnotemark[\value{footnote}].
 350
 351                 These revised lecture notes are from a course on the \gls{MTASK} simulator was provided at the 2018 \gls{CEFP}\slash{}\gls{3COWS} winter school in Ko\v{s}ice, Slovakia.
 352 %               \paragraph{Contribution}
 353 %               Pieter Koopman wrote and taught it, I helped with the software and research.
 354         \item \emph{Writing Internet of Things Applications with Task Oriented Programming} \citep{lubbers_writing_2019}\footnotemark[\value{footnote}].
 355
 356                 These revised lecture notes are from a course on programming in \gls{IOT} systems using \gls{MTASK} provided at the 2019 \gls{CEFP}\slash{}\gls{3COWS} summer school in Budapest, Hungary.
 357 %               \paragraph{Contribution}
 358 %               Pieter Koopman prepared and taught half of the lecture and supervised the practical session.
 359 %               I taught the other half of the lecture, wrote the lecture notes, made the assignments and supervised the practical session.
 360         \item \emph{Interpreting Task Oriented Programs on Tiny Computers} \citep{lubbers_interpreting_2019}.
 361
 362                 This paper shows an implementation for \gls{MTASK} for microcontrollers.
 363 %               \paragraph{Contribution}
 364 %               The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer.
 365         \item \emph{Reducing the Power Consumption of IoT with Task-Oriented Programming} \citep{crooijmans_reducing_2022}.
 366
 367                 This paper shows how to create a scheduler so that devices running \gls{MTASK} tasks can go to sleep more automatically and how interrupts are incorporated in the language.
 368 %               \paragraph{Contribution}
 369 %               The research was carried out by \citet{crooijmans_reducing_2021} during his Master's thesis.
 370 %               I did the daily supervision and helped with the research, Pieter Koopman was the formal supervisor and wrote most of the paper.
 371         \item \emph{Green Computing for the Internet of Things} \citep{lubbers_green_2022}\footnote{
 372                 This work acknowledges the support of the Erasmus+ project ``SusTrainable---Promoting Sustainability as a Fundamental Driver in Software Development Training and Education'', no. 2020--1--PT01--KA203--078646}.
 373
 374                 These revised lecture notes are from a course on sustainable \gls{IOT} programming with \gls{MTASK} provided at the 2022 SusTrainable summer school in Rijeka, Croatia.
 375
 376 %               \paragraph{Contribution}
 377 %               These revised lecture notes are from a course on sustainable programming using \gls{MTASK} provided at the 2022 SusTrainable summer school in Rijeka, Croatia.
 378 %               Pieter prepared and taught a quarter of the lecture and supervised the practical session.
 379 %               I prepared and taught the other three quarters of the lecture, made the assignments and supervised the practical session
 380 \end{itemize}
 381
 382 \paragraph{Contribution:}
 383 The original imperative predecessors the \gls{MTASK} language and their initial interpretations were developed by Pieter Koopman and Rinus Plasmeijer.
 384 I continued with the language; developed the byte code interpreter, the precursor to the \gls{C} code generation interpretation; the integration with \gls{ITASK}; and the \gls{RTS}.
 385 The paper of which I am first author are solely written by me.
 386
 387 \subsection{\nameref{prt:tvt}}
 388 \Cref{prt:tvt} is based on a journal paper that quantitatively and qualitatively compares traditional \gls{IOT} architectures with \gls{IOT} systems using \gls{TOP} and contains a single chapter.
 389 This chapter is based on the journal paper: \emph{Could Tierless Programming Reduce IoT Development Grief?} \citep{lubbers_could_2022}\footnote{This work is an extension of the conference article: \emph{Tiered versus Tierless IoT Stacks: Comparing Smart Campus Software Architectures} \citep{lubbers_tiered_2020}\footnotemark.}.
 390 \footnotetext{This paper was partly funded by the 2019 Radboud-Glasgow Collaboration Fund.}
 391
 392 It compares programming traditional tiered architectures to tierless architectures by showing a qualitative and a quantitative four-way comparison of a smart-campus application.
 393
 394 \paragraph{Contribution:}
 395 Writing the paper was performed by all authors.
 396 I created the server application, the \gls{CLEAN}\slash{}\gls{ITASK}\slash{}\gls{MTASK} implementation (\glsxtrshort{CWS}) and the \gls{CLEAN}\slash{}\gls{ITASK} implementation (\glsxtrshort{CRS})
 397 Adrian Ramsingh created the \gls{MICROPYTHON} implementation (\glsxtrshort{PWS}), the original \gls{PYTHON} implementation (\glsxtrshort{PRS}) and the server application were created by \citet{hentschel_supersensors:_2016}.
 398
 399 \input{subfilepostamble}
 400 \end{document}