http://www.jsoftware.com/jwiki/Essays/Covert%20Representation
On Mon, Apr 2, 2012 at 3:51 AM, Edward Mokurai Cherlin < moku...@sugarlabs.org> wrote: > On Sun, April 1, 2012 2:51 pm, Raul Miller wrote: > > P.S. after reading your example and seeing that you > > using the shape (with a prefix of 0) to hold the data > > I am wondering if this was meant to be an april fool's > > joke? > > I have observed that it is possible, in a hypothetical way, to > represent any computable function using only empty arrays if we have > no limitation on the number of dimensions. A Computer Science fact > that is also a joke. > > I wrote another joke of this kind in APL News once long ago, > concerning a utility for printing sideways on fan-fold paper. It is > not difficult to prove that any computable function can be written in > one line of APL, and this provided a way of printing it. A single box > of 5000 sheets of fanfold paper was not quite a mile long. > > This is the sort of thing that got me my own entry in Stan > Kelly-Bootle's Computer Contradictionary, along with a two-page > article consisting entirely of empty array jokes for use in teaching, > as suggested by Jim Brown, then of IBM; and winning one of Stan's > programming contests in Unix Review. The programming contest was for > the maximum ratio of error text to program text. I submitted the APL > version of > > ".x=.'".x' > > which fills memory with stack frames, and then sets about displaying > them all in the WS FULL or equivalent error message. Again, this is > both joke and fact. APL implementors use such expressions to test the > quality of their memory handling, in particular whether they have > saved enough memory in WS FULL situations to handle generating the > error message--obviously without creating it as an object in the > workspace first. > > > -- > > Raul > > -- > Edward Mokurai (默雷/निशब्दगर्ज/نشبدگرج) Cherlin > Silent Thunder is my name, and Children are my nation. > The Cosmos is my dwelling place, the Truth my destination. > http://wiki.sugarlabs.org/go/Replacing_Textbooks > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
