Pail is an esoteric programming language based on pairs; just as Lisp stands for LISt Processing, Pail stands for PAIr Language.
This is the reference distribution for Pail.
The Pail programming language is documented in the literate Haskell
source code of its reference interpreter,
Pail.lhs, which can be
found in the
The literate Haskell was written as if it were Markdown, so you might (or might not) have luck looking at it as such in a browsing interface:
Some tests, in Falderal format, which might clarify the intended
behaviour, can be found in
Pail.md in the
These files are distributed under a 3-clause BSD license. See the file
LICENSE for the license text.
There is also a demonstration of running the Pail interpreter in
with the Haste compiler. You can try this locally by building
demo/pail.js and opening
demo/pail.html in a web browser.
For more information on the language, see the Pail entry at Cat's Eye Technologies.