ISWIM | EPFL Graph Search

Are you an EPFL student looking for a semester project?

Work with us on data science and visualisation projects, and deploy your project as an app on top of GraphSearch.

ISWIM (acronym for If you See What I Mean) is an abstract computer programming language (or a family of languages) devised by Peter Landin and first described in his article "The Next 700 Programming Languages", published in the Communications of the ACM in 1966. Although not implemented, it has proved very influential in the development of programming languages, especially functional programming languages such as SASL, Miranda, ML, Haskell and their successors, and dataflow programming languages like Lucid. ISWIM is an imperative programming language with a functional core, consisting of a syntactic sugaring of lambda calculus to which are added mutable variables and assignment and a powerful control mechanism: the program point operator. Being based on lambda calculus, ISWIM has higher-order functions and lexically scoped variables. The operational semantics of ISWIM are defined using Landin's SECD machine and use call-by-value, that is eager evaluation. A goal of ISWIM was to look more like mathematical notation, so Landin abandoned ALGOL's semicolons between statements and begin ... end blocks and replaced them with the off-side rule and scoping based on indentation. A notationally distinctive feature of ISWIM is its use of where clauses. An ISWIM program is a single expression qualified by where clauses (auxiliary definitions including equations among variables), conditional expressions and function definitions. Along with CPL, ISWIM was one of the first programming languages to use where clauses. A notable semantic feature was the ability to define new data types, as a (possibly recursive) sum of products. This was done using a somewhat verbose natural language style description, but apart from notation amounts exactly to the algebraic data types found in modern functional languages. ISWIM variables did not have explicit type declarations and it seems likely (although not explicitly stated in the 1966 paper) that Landin intended the language to be dynamically typed, like LISP and unlike ALGOL; but it is also possible that he intended to develop some form of type inference.

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (6)

Related units (1)

Related concepts (12)

DatAFLow: Toward a Data-flow-guided Fuzzer

Mathias Josef Payer

This Replicating Computational Report (RCR) describes (a) our datAFLow fuzzer and (b) how to replicate the results in "datAFLow: Toward a Data-Flow-Guided Fuzzer." Our primary artifact is the datAFLow fuzzer. Unlike traditional coverage-guided greybox fuzz ...

2023

Composite Data Types in Dynamic Dataflow Languages as Copyless Memory Sharing Mechanism

Marco Mattavelli, Endri Bezati, Aurélien François Gilbert Bloch

This paper presents new optimization approaches aiming at reducing the impact of memory accesses on the performance of dataflow programs. The approach is based on introducing a high level management of composite data types in dynamic dataflow programming l ...

2019

Symbolic Resource Bound Inference

Viktor Kuncak, Ravichandhran Kandhadai Madhavan

We present an approach for inferring symbolic resource bounds for purely functional programs consisting of recursive functions, algebraic data types and nonlinear arithmetic operations. In our approach, the developer specifies the desired shape of the boun ...

2014

Programming language theory

Programming language theory (PLT) is a branch of computer science that deals with the design, implementation, analysis, characterization, and classification of formal languages known as programming languages. Programming language theory is closely related to other fields including mathematics, software engineering, and linguistics. There are a number of academic conferences and journals in the area. History of programming languages and Programming language#History In some ways, the history of programming language theory predates even the development of programming languages themselves.

Haskell

Haskell (ˈhæskəl) is a general-purpose, statically-typed, purely functional programming language with type inference and lazy evaluation. Designed for teaching, research, and industrial applications, Haskell has pioneered a number of programming language features such as type classes, which enable type-safe operator overloading, and monadic input/output (IO). It is named after logician Haskell Curry. Haskell's main implementation is the Glasgow Haskell Compiler (GHC).

Algebraic data type

In computer programming, especially functional programming and type theory, an algebraic data type (ADT) is a kind of composite type, i.e., a type formed by combining other types. Two common classes of algebraic types are product types (i.e., tuples and records) and sum types (i.e., tagged or disjoint unions, coproduct types or variant types). The values of a product type typically contain several values, called fields. All values of that type have the same combination of field types.