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10th letter of the alphabetalphabet
[Gr. alpha-beta, like Eng. ABC], system of writing, theoretically having a one-for-one relation between character (or letter) and phoneme (see phonetics). Few alphabets have achieved the ideal exactness.
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, a Western European medieval development of I, with which it was formerly quite interchangeable in writing. It is pronounced as a consonant in English and often as a y in other languages, as in the Hebrew hallelujah.




A unit of energy or work; equals the work done by a force of 1 newton which acts over a distance of 1 metre in the direction of the force.


A derivative and redesign of APL with added features and control structures. J is purely functional with lexical scope and more conventional control structures, plus several new concepts such as function rank and function arrays. J was designed and developed by Kennneth E. Iverson and Roger Hui <hui@yrloc.ipsa.reuter.com>. J uses only the ASCII character set but has a spelling scheme that retains the advantages of APL's special alphabet. J is a conventional procedural programming language but can be used as a purely functional language.

Version 4.1 for MS-DOS, Sun, Mac, Archimedes. Source available in C from Iverson Software, +1 (416) 925 6096.

Version 6 package from ISI includes an interpreter and tutorial. Ported to DEC, NeXT, SGI, Sun-3, Sun-4, Vax, RS/6000, MIPS, Macintosh, Acorn Archimedes, IBM PC, Atari, 3b1, Amiga.


J-mode GNU Emacs macros available by ftp://think.com/pub/j/gmacs/j-interaction-mode.el.

["APL\?", Roger K.W. Hui et al, APL90 Conf Proc, Quote Quad 20(4):192-200].


A high-level mathematical programming language developed by Kenneth Iverson, the author of APL. J is the successor to APL and runs on a variety of platforms, including DOS, Windows, OS/2, Unix and the Macintosh. The Windows version can be used as a calculating engine for Visual Basic, in which Visual Basic is used to write the file handling and user interface portions, and J is used to program the math.