An Introduction to iTasks: Defining Interactive Work Flows for the Web

Higher-Order Symb Comput

et al. 2010

The Trends in Functional Programming Symposia are an annual event dedicated to promoting new research directions in functional programming and to investigating the relationship between functional programming and other branches of Computer Science. The TFP series started in 1999 and the 2008 meeting marked the first decade of the symposium. In this paper we identify and discuss the trends presented at TFP using a macro-vision lens that looks at topics in the first two volumes of TFP and the two most recent volumes of TFP. The goal is to calibrate how trends have changed over a decade instead of analyzing trends with a micro-vision lens that focuses on changes from year to year. The major trends identified are work on parallel functional programming, types, formal verification, implementation of functional languages, and application development.

Section: Inter-language Operability and Functional Languages For The Webmentioning

confidence: 99%

Trends in Trends in Functional Programming 1999/2000 versus 2007/2008

Achten

Eekelen

Higher-Order Symb Comput

et al. 2010

“…The tasks perform real world or artificial units of work, like providing information, make decisions based on information (provided by other tasks), start other tasks, or change something in the real world. Currently the iTask system [31] is the main implementation of this paradigm. Interaction of TOP software with users is done via the browser.…”

Section: Introductionmentioning

confidence: 99%

Type-Safe Functions and Tasks in a Shallow Embedded DSL for Microprocessors

Central European Functional Programming School

Plasmeijer

2019

The Internet of Things, IoT, brings us large amounts of connected computing devices that are equipped with dedicated sensors and actuators. These computing devices are typically driven by a cheap microprocessor system with a relatively slow processor and a very limited amount of memory. Due to the special input-output capabilities of IoT devices and their connections it is very attractive to execute (parts of) programs on these microcomputers.Task-oriented programming, as introduced in the iTask framework, offers a very convenient abstraction level to construct distributed programs at a high level of abstraction. The task concept basically introduces lightweight threads. Tasks can be composed to more powerful tasks by a flexible set of combinators. These tasks can communicate with each other via shared data sources and inspect intermediate task values of other tasks.The IoT devices considered here are far from powerful enough to execute programs made within the standard iTask system. To facilitate the execution of simple tasks using the special capabilities of the IoT devices from the iTask environment, we introduce a type-safe multi-view extendable domain-specific language to specify tasks for IoT devices. This domain specific language is embedded in the iTask system to facilitate the integration of both systems, but those systems are very useful on their own.

“…For the implementation of the simple programming language SAPL we reinvented this encoding [20,21]. SAPL is used to execute Clean code of an iTask program in the browser [33]. Naylor and Runciman used the ideas from SAPL in the implementation of the Reduceron [28].…”

Section: Introductionmentioning

confidence: 99%

Church Encoding of Data Types Considered Harmful for Implementations

Proceedings of the 26nd 2014 International Symposium on Implementation and Application of Functional Languages

Plasmeijer

Jansen

2014

From the λ-calculus it is known how to represent (recursive) data structures by ordinary λ-terms. Based on this idea one can represent algebraic data types in a functional programming language by higher-order functions. Using this encoding we only have to implement functions to achieve an implementation of the functional language with data structures. In this paper we compare the famous Church encoding of data types with the less familiar Scott and Parigot encodings.We show that one can use the encoding of data types by functions in a Hindley-Milner typed language by adding a single constructor for each data type. In an untyped context, like an efficient implementation, this constructor can be omitted. By collecting the basic operations of a data type in a type constructor class and providing instances for the various encodings, these encodings can coexist in a single program. By changing the instance of this class we can execute the same algorithm in a different encoding. This makes it easier to compare the encodings with each other.We show that in the Church encoding selectors of constructors yielding the recursive type, like the tail of a list, have an undesirable strictness in the spine of the data structure. The Scott and Parigot encodings do not hamper lazy evaluation in any way. The evaluation of the recursive spine by the Church encoding makes the complexity of these destructors linear time. The same destructors in the Scott and the Parigot encoding requires only constant time. Moreover, the Church encoding has problems with sharing reduction results of selectors. The Parigot encoding is a combination of the Scott and Church encoding. Hence we might expect that it combines the best of both worlds, but in practice it does not offer any advantage over the Scott encoding.