Who discovered the fold operation?
Hi Folks, Scientists look for recurring patterns in nature. Once a pattern is discovered, its essential ingredients are identified and formalized into a law or mathematical equation. Discovery of a pattern is important and those individuals who make such discoveries are rightfully acknowledged in our annals of science. Scientists are not the only ones that look for recurring patterns, so do functional programmers. Once a pattern is discovered, its essential ingredients are identified and formalized into a function. Long ago someone in the functional programming community discovered a pattern that has become known as the fold operation. It was an important discovery, on-par with some scientific discoveries. Who discovered the fold operation? When? /Roger
On 07/09/12 18:58, Costello, Roger L. wrote:
Hi Folks,
Scientists look for recurring patterns in nature. Once a pattern is discovered, its essential ingredients are identified and formalized into a law or mathematical equation. Discovery of a pattern is important and those individuals who make such discoveries are rightfully acknowledged in our annals of science.
Scientists are not the only ones that look for recurring patterns, so do functional programmers. Once a pattern is discovered, its essential ingredients are identified and formalized into a function.
Long ago someone in the functional programming community discovered a pattern that has become known as the fold operation. It was an important discovery, on-par with some scientific discoveries.
Who discovered the fold operation? When?
/Roger
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-- Tony Morris http://tmorris.net/
For foldr see Olivier Danvy and Michael Spivey's "On Barron and Strachey’s Cartesian Product Function" crediting a discovery to David Barron and Christopher Strachey. http://www.brics.dk/RS/07/14/BRICS-RS-07-14.pdf
On Fri, Sep 7, 2012 at 8:37 PM, Stephen Tetley
For foldr see Olivier Danvy and Michael Spivey's "On Barron and Strachey’s Cartesian Product Function" crediting a discovery to David Barron and Christopher Strachey.
That gives the date as 1966. APL had the fold operator -- called 'reduce' in APL terminology and notated with a slash '/' -- from around 1960 http://www.softwarepreservation.org/projects/apl/book/APROGRAMMING%20LANGUAG... is the 1962 book. Apl as a notation had existed some time before that.
participants (4)
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Costello, Roger L. -
Rustom Mody -
Stephen Tetley -
Tony Morris