T is a dialect of the Scheme programming language developed in the early 1980s by Jonathan A. Rees, Kent M. Pitman, and Norman I. Adams of Yale University as an experiment in language design and implementation.

Rationale

T's purpose is to test the thesis developed by Guy L. Steele Jr. and Gerald Jay Sussman in their series of papers about Scheme: that Scheme may be used as the basis for a practical programming language of exceptional expressive power, and that implementations of Scheme could perform better than other Lisp systems, and competitively with implementations of programming languages, such as C and BLISS, which are usually considered to be inherently more efficient than Lisp on conventional machine architectures. Much of this occurs via an optimizing compiler named Orbit.

T contains some features that modern Scheme lacks. For example, T is object-oriented, and it has first-class environments, called locales, which can be modified non-locally and used as a module system. T has several extra special forms for lazy evaluation and flow control, and an equivalent to Common Lisp's setf. T, like Scheme, supports call-with-current-continuation (call/cc), but it also has a more limited form called catch. From the T manual, a hypothetical implementation of cons could be:

This example shows that objects in T are intimately related to closures and message-passing. A primitive called join puts two objects together, allowing for something resembling inheritance.

Timeline of Lisp dialectsvte
19581960196519701975198019851990199520002005201020152020
LISP 1, 1.5, LISP 2(abandoned)
Maclisp
Interlisp
MDL
Lisp Machine Lisp
SchemeR5RSR6RSR7RS small
NIL
ZIL (Zork Implementation Language)
Franz Lisp
muLisp
Common LispANSI standard
Le Lisp
MIT Scheme
XLISP
T
Chez Scheme
Emacs Lisp
AutoLISP
PicoLisp
Gambit
EuLisp
ISLISP
OpenLisp
PLT SchemeRacket
newLISP
GNU Guile
Visual LISP
Clojure
Arc
LFE
Hy

Ports

T was ported to many hardware platforms and operating systems, including:

See also

External links

  • , by Olin Shivers
  • (PDF) from ReadScheme, via the Internet Archive