SISAL (Streams and Iteration in a Single Assignment Language) is a general-purpose

single assignment In computer programming, an assignment statement sets and/or re-sets the value stored in the storage location(s) denoted by a variable name; in other words, it copies a value into the variable. In most imperative programming languages, the ass ...

functional Functional may refer to: * Movements in architecture: ** Functionalism (architecture) ** Form follows function * Functional group, combination of atoms within molecules * Medical conditions without currently visible organic basis: ** Functional s ...

programming language A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually def ...

with strict semantics,

implicit parallelism In computer science, implicit parallelism is a characteristic of a programming language that allows a compiler or interpreter to automatically exploit the parallelism inherent to the computations expressed by some of the language's constructs ...

, and efficient

array An array is a systematic arrangement of similar objects, usually in rows and columns. Things called an array include: {{TOC right Music * In twelve-tone and serial composition, the presentation of simultaneous twelve-tone sets such that the ...

handling. SISAL outputs a

dataflow In computing, dataflow is a broad concept, which has various meanings depending on the application and context. In the context of software architecture, data flow relates to stream processing or reactive programming. Software architecture Dat ...

graph in Intermediary Form 1 (IF1). It was derived from the Value-oriented Algorithmic Language (VAL), designed by

Jack Dennis Jack Bonnell Dennis (born October 13, 1931) is an American computer scientist and Emeritus Professor of Computer Science and Engineering at Massachusetts Institute of Technology. The work of Dennis in computer systems and computer languages is ...

, and adds

recursion Recursion occurs when the definition of a concept or process depends on a simpler or previous version of itself. Recursion is used in a variety of disciplines ranging from linguistics to logic. The most common application of recursion is in m ...

and finite streams. It has a Pascal-like syntax and was designed to be a common

high-level programming language A high-level programming language is a programming language with strong Abstraction (computer science), abstraction from the details of the computer. In contrast to low-level programming languages, it may use natural language ''elements'', be ea ...

for numerical programs on a variety of

multiprocessor Multiprocessing (MP) is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. The ...

History

SISAL was defined in 1983 by James McGraw et al., at the

University of Manchester The University of Manchester is a public university, public research university in Manchester, England. The main campus is south of Manchester city centre, Manchester City Centre on Wilmslow Road, Oxford Road. The University of Manchester is c ...

Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory (LLNL) is a Federally funded research and development centers, federally funded research and development center in Livermore, California, United States. Originally established in 1952, the laboratory now i ...

(LLNL),

Colorado State University Colorado State University (Colorado State or CSU) is a Public university, public Land-grant university, land-grant research university in Fort Collins, Colorado, United States. It is the flagship university of the Colorado State University Syst ...

and

Digital Equipment Corporation Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until ...

(DEC). It was revised in 1985, and the first

compiled In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that ...

implementation Implementation is the realization of an application, execution of a plan, idea, scientific modelling, model, design, specification, Standardization, standard, algorithm, policy, or the Management, administration or management of a process or Goal ...

was made in 1986. Its performance is superior to C and rivals Fortran, according to some sources,Retire Fortran?: a debate rekindled, David Cann, August 1992, Communications of the ACM, Volume 35, Issue 8 combined with efficient and automatic parallelization. SISAL's name came from

grep grep is a command-line utility for searching plaintext datasets for lines that match a regular expression. Its name comes from the ed command g/re/p (global regular expression search and print), which has the same effect. grep was originally de ...

ping "sal" for "Single Assignment Language" from the Unix dictionary /usr/dict/words. Versions exist for the

Cray Cray Inc., a subsidiary of Hewlett Packard Enterprise, is an American supercomputer manufacturer headquartered in Seattle, Washington. It also manufactures systems for data storage and analytics. Several Cray supercomputer systems are listed ...

X-MP, Y-MP, 2;

Sequent In mathematical logic, a sequent is a very general kind of conditional assertion. : A_1,\,\dots,A_m \,\vdash\, B_1,\,\dots,B_n. A sequent may have any number ''m'' of condition formulas ''Ai'' (called " antecedents") and any number ''n'' of ass ...

, Encore Alliant, DEC DEC VAX-11/784,

architectures, KSR1,

Inmos Inmos International plc (trademark INMOS) and two operating subsidiaries, Inmos Limited (UK) and Inmos Corporation (US), was a British semiconductor company founded by Iann Barron, Richard Petritz, and Paul Schroeder in July 1978. Inmos Limited ...

Transputer The transputer is a series of pioneering microprocessors from the 1980s, intended for parallel computing. To support this, each transputer had its own integrated memory and serial communication links to exchange data with other transputers. ...

s, and

systolic array In parallel computer architectures, a systolic array is a homogeneous network of tightly coupled data processing units (DPUs) called cells or nodes. Each node or DPU independently computes a partial result as a function of the data received fro ...

Architecture

The requirements for a fine-grain parallelism language are better met with a

dataflow programming In computer programming, dataflow programming is a programming paradigm that models a program as a directed graph of the data flowing between operations, thus implementing dataflow principles and architecture. Dataflow programming languages share ...

language than a

system programming language A system programming language is a programming language used for system programming; such languages are designed for writing system software, which usually requires different development approaches when compared with application software. Eds ...

. SISAL is more than just a dataflow and fine-grain language. It is a set of tools that convert a textual human readable dataflow language into a graph format (named ''IF1'' - Intermediary Form 1). Part of the SISAL project also involved converting this graph format into runnable C code.

SISAL Renaissance Era

In 2010 SISAL saw a brief resurgence when a group of undergraduates at

Worcester Polytechnic Institute The Worcester Polytechnic Institute (WPI) is a Private university, private research university in Worcester, Massachusetts, United States. Founded in 1865, WPI was one of the United States' first engineering and technology universities and now h ...

investigated implementing a fine-grain parallelism backend for the SISAL language.Fine-Grain Parallelism: An Investigative Study into the merits of Graphical Programming and a Fine-grain Execution Mode
/ref> In 2018 SISAL was modernized with indent-based syntax, first-class functions, lambdas, closures and lazy semantics within a project SISAL-IS.Modernized Sisal Interpreter (MSInt)
/ref>

References

Notes

Bibliography

VAL Overview

{{refend

External links

SISAL Parallel Programming
SourceForge.net project page Concurrent programming languages Functional languages