Background

Whitespace is an [imperative], [stack]-based [programming language], freely available under the [GPL]. The thing that really sets Whitespace apart from other programming languages is that the only valid syntactic [symbol]s are [space], [tab] and [line feed]; all other [symbol]s are totally ignored as comments. This means that a progam can, and often will, be entirely made up of white space, hence the name.

The first version was released on April 1st, 2003, and despite all indications to the contrary, the man responsible, [Edwin Brady] claims this date is merely a coincidence. At the time of writing, Whitespace has reached version 0.3, with new instructions facilitating [recursion], albeit in a very [convoluted] and [obfuscated] manner.

Details

Whereas in `normal' languages such as [Java], [statement]s are delimited by [semi-colon]s, and [token]s by whitespace, Whitespace has no such luxury. Statement [syntax] has been cleverly crafted so as to make it [unambiguous] where one statement ends and another begins, despite there being no explicit marker. Statements have a [hierarchical] structure, with the first one or two tokens deciding the general type of operation, and the next one or two deciding the exact operation to be performed, followed by an [argument] in some cases. Arguments can be [integer]s or [character]s, although both are given in [binary], with the [most significant bit] indicating the [sign]. For the complete [syntax], see http://compsoc.dur.ac.uk/whitespace/.

Conclusion

In the [FAQ], the creator himself, [Edwin Brady], admits,

Is there a practical use for Whitespace?

I doubt it.

That said, [hand waving|I am pretty sure] Whitespace is [Turing complete], that is; it is [equipotent] with any programming language you would care to mention. [Java], [C], [ML], whatever. Although Whitespace is most certainly tongue-in-cheek, it is still fully functional, being about as syntactically developed as [assembly code]. Despite this, I think it will be a few years before we see [Microsoft] Visual Whitespace [compiler]s appearing on the market.

At the moment, Whitespace is available in [Haskell] [source code] and [Linux] [binary] format. If you are planning on reading/writing Whitespace, I recommend the [Emacs] [major-mode] WS, which prints [space]s and [tab]s explicitly (see below).

An example

You will forgive me if I do not create a large example - [E2]'s storage can be put to better use; "Hello world!", for example, is 87 lines long and reasonably unfathomable. Here is a program that instead just prints "HI".

Translated into the view you get from [Emacs]:

START[SPC][SPC][SPC][TAB][SPC][SPC][TAB][SPC][SPC][TAB]
[SPC][SPC][SPC][TAB][SPC][SPC][TAB][SPC][SPC][SPC]
[TAB]
[SPC][SPC][TAB]
[SPC][SPC]


END

In English:

  Push ASCII code 73 (I) onto stack
  Push ASCII code 71 (H) onto stack
  Output character on top of stack
  Output character on top of stack
  End

The result:

~/bin$ wspace hi.ws
HI