SAC programming language
Encyclopedia
SAC is a strict purely functional programming language
which design is focused on the needs of numerical applications. Emphasis is laid on efficient support for array processing
. Efficiency concerns are essentially twofold. On the one hand, efficiency in program development is to be improved by the opportunity to specify array operations on a high level of abstraction
. On the other hand, efficiency in program execution, i.e. the runtime performance of programs, in time and memory consumption, is still to be achieved by sophisticated compilation
schemes. Only as far as the latter succeeds, the high-level style of specifications can actually be called useful.
To facilitate compiling to efficiently executable code, certain functional language features which are not considered essential for numerical applications, e.g. higher-order functions, polymorphism, or lazy evaluation
, are not (yet) supported by SAC. These may be found in general-purpose functional languages, e.g. Haskell
, Clean
, Miranda
, or ML
.
To overcome the acceptance problems encountered by other functional or array based languages intended for numerical / array intensive applications, e.g. SISAL
, NESL
, Nial
, APL
, J, or K, particular regard is paid to ease the transition from a C
/ Fortran
like programming environment to SAC.
In more detail, the basic language design goals of SAC are to:
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
which design is focused on the needs of numerical applications. Emphasis is laid on efficient support for array processing
Array processing
Array processing is signal processing of the outputs of an array of sensors to:* Enhance the signal-to-interference-plus-noise ratio compared to that of a single sensor using conventional or adaptive beamforming....
. Efficiency concerns are essentially twofold. On the one hand, efficiency in program development is to be improved by the opportunity to specify array operations on a high level of abstraction
Abstraction
Abstraction is a process by which higher concepts are derived from the usage and classification of literal concepts, first principles, or other methods....
. On the other hand, efficiency in program execution, i.e. the runtime performance of programs, in time and memory consumption, is still to be achieved by sophisticated compilation
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...
schemes. Only as far as the latter succeeds, the high-level style of specifications can actually be called useful.
To facilitate compiling to efficiently executable code, certain functional language features which are not considered essential for numerical applications, e.g. higher-order functions, polymorphism, or lazy evaluation
Lazy evaluation
In programming language theory, lazy evaluation or call-by-need is an evaluation strategy which delays the evaluation of an expression until the value of this is actually required and which also avoids repeated evaluations...
, are not (yet) supported by SAC. These may be found in general-purpose functional languages, e.g. Haskell
Haskell (programming language)
Haskell is a standardized, general-purpose purely functional programming language, with non-strict semantics and strong static typing. It is named after logician Haskell Curry. In Haskell, "a function is a first-class citizen" of the programming language. As a functional programming language, the...
, Clean
Clean programming language
In computer science, Clean is a general-purpose purely functional computer programming language.-Features:The language Clean first appeared in 1987 and is still further developed; it shares many properties with Haskell:...
, Miranda
Miranda programming language
Miranda is a non-strict purely functional programming language designed by David Turner as a successor to his earlier programming languages SASL and KRC, using some concepts from ML and Hope. It was produced by Research Software Ltd...
, or ML
ML programming language
ML is a general-purpose functional programming language developed by Robin Milner and others in the early 1970s at the University of Edinburgh, whose syntax is inspired by ISWIM...
.
To overcome the acceptance problems encountered by other functional or array based languages intended for numerical / array intensive applications, e.g. SISAL
SISAL
SISAL is a general-purpose single assignment functional programming language with strict semantics, implicit parallelism, and efficient array handling. SISAL outputs a dataflow graph in Intermediary Form 1...
, NESL
NESL
NESL is a parallel programming language developed at Carnegie Mellon by the SCandAL project and released in 1993. It integrates various ideas from parallel algorithms, and functional programming and array programming languages....
, Nial
Nial
Nial is a high-level array programming language developed from about 1981 by Mike Jenkins of Queen's University, Kingston, Ontario, Canada....
, APL
APL programming language
APL is an interactive array-oriented language and integrated development environment, which is available from a number of commercial and noncommercial vendors and for most computer platforms. It is based on a mathematical notation developed by Kenneth E...
, J, or K, particular regard is paid to ease the transition from a C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
/ Fortran
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
like programming environment to SAC.
In more detail, the basic language design goals of SAC are to:
- provide a purely functional language with a syntax very similar to that of C in order to ease, for a large community of programmers, the transition from an imperative to a functional programming style;
- support multi-dimensional arrays as first class objects;
- allow the specification of shape- and dimension-invariant array operations;
- provide high-level array operations that liberate programming from tedious and error-prone specifications of starts, stops and strides for array traversals thereby improving code reusabilityCode reuseCode reuse, also called software reuse, is the use of existing software, or software knowledge, to build new software.-Overview:Ad hoc code reuse has been practiced from the earliest days of programming. Programmers have always reused sections of code, templates, functions, and procedures...
and programming productivityProgramming productivityProgramming productivity refers to a variety of software development issues and methodologies affecting the quantity and quality of code produced by an individual or team...
, in general. - incorporate a module system that allows for separate compilation, separate name spaces, and abstract data types, and, additionally, provides an interface to foreign languages in order to enable reuse of existing code;
- provide means for a smooth integration of states and state modifications into the functional paradigm based on uniqueness types;
- use the module system, the foreign language interface, and the integration of states in order to create a standard library which provides a functionality similar to that of the standard C libraries, e.g. powerful I/O facilities or mathematical functions;
- facilitate the compilation to host machine code which can be efficiently executed both in terms of time and space demand;
- facilitate the compilation for non-sequential program execution in multiprocessorMultiprocessorComputer system having two or more processing units each sharing main memory and peripherals, in order to simultaneously process programs.Sometimes the term Multiprocessor is confused with the term Multiprocessing....
environments.