S[1] is a statistical programming language developed primarily by John Chambers and (in earlier versions) Rick Becker, Trevor Hastie, William Cleveland and Allan Wilks of Bell Laboratories.
The aim of the language, as expressed by John Chambers, is "to turn ideas into software, quickly and faithfully".
[2], but has now been superseded by the partially backwards compatible [3] R language, a part of the GNU free software project[4].
Up to that time, much of the statistical computing was done by directly calling Fortran subroutines; however, S was designed to offer an alternate and more interactive approach, motivated in part by exploratory data analysis advocated by John Tukey.
[5] Early design decisions that hold even today include interactive graphics devices (printers and character terminals at the time), and providing easily accessible documentation for the functions.
Many other changes to S took hold, such as the use of X11 and PostScript graphics devices, rewriting many internal functions from Fortran to C, and the use of double precision (only) arithmetic.