10 Dec
2009
10 Dec
'09
7:28 p.m.
On Dec 9, 2009, at 4:00 AM, Robin Green wrote:
At Thu, 10 Dec 2009 12:07:32 +0000, Magnus Therning wrote:
As I understand it it all started with laziness. I don't know if laziness is impossible without purity
More or less.
The S programming language, used for statistics, - is not pure - DOES have lazy evaluation of arguments. (For a free version, see www.r-project.org.) I suspect that the original motivation for this was so that plot(temperature, pressure) could automatically get "temperature" on the horizontal axis and "pressure" on the vertical axis, but it is also used as a lazy evaluation mechanism. In practice, a lot of S code is close to functional.