APL

APL (To Programing Language, also known as Array Processing Language for some years) is an interpreted IBM, programming language developed by Kenneth Iverson, year 60.

It is a very concise language, with a very simple syntax. It is oriented to works with parent companies, with which all type of operations logics or mathematics can be done. New matrix operations can even be defined.

It is of a tremendous power. A single sentence can be translated in thousands of them in other languages, like for example Fortran. Like example, the language of simulation of circuits, SIAL, occupied near 25 000 sentences in Fortran-Assembler and, to the being rewritten in APL, all the program it was possible to be printed in two folios. On the other hand, in spite of being a language of so high level, also he is able to manipulate concerning bits and has interfaces with programming languages of low level (C, assembler…) by means of the calls auxiliary processors.

It has the property of which from a routine it is possible to be created, to be compiled and to be executed, in run time, others, which makes for the manufacture of compilers and interpreters very appropriate.

Their problems are in which: 1) It needs special keyboard to put and symbolic the logic operators. 2) The written programmes in APL are so concise that they are difficult to document and to include/understand.

Applications of the APL

The APL, to the so concise being, is a language that allows a very quick development cycle. On the other hand, to the interpreted being, the speed of execution is typically slower than the one of the compiled programming languages. For this reason, a good language for the development of prototypes is considered.

Between his known applications more it is his use in the Tron film de Walt Disney for the generation of the special effects, and in the system Deep Blue of IBM that vencío to Kasparov to the chess.

Like curiosity, in the novel Cheap Complex Devices de J.C. Sundman, the author affirms that the content of the book has been generated automatically by a computer written in APL, which has been worth him the premium Douglas R. Hofstadter of novel creation by computer in 1997. All this, naturally, is a literary artifice.

Successors of the APL

Kenneth Iverson, later, was to the front of the development of a programming language that appeared like the APL successor, call J. One of the particular characteristics of J is what it has occurred in denominating tacit functional programming; where it is considered that to express programs it is not necessary to name variable, nor parameters to functions (These concepts of tacit programming have been incorporated to the language Logo in the LogoFE library). In J, the variety of the routines that in APL are called operators are much greater.

References

• M. Alfonseca, SIAL/71 “, to Continuous Simulation Compiler”, in “Advances in Cybernetics and Systems”, Ed. J. Rose, Gordon and Breach, London, Vol. 3, 1974, 1319-1340.

• David Selby, “Jottings from the business intelligence jungle”. In APL '02: Proceedings of the 2002 conference on APL, 2002, pages 190-197.

• 'http://www.wetmachine.com/cheap/chapter1.shtml'