<br><br><div class="gmail_quote">On Fri, Sep 7, 2012 at 8:37 PM, Stephen Tetley <span dir="ltr"><<a href="mailto:stephen.tetley@gmail.com" target="_blank">stephen.tetley@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
For foldr see Olivier Danvy and Michael Spivey's "On Barron and<br>
Strachey’s Cartesian Product Function" crediting a discovery to David<br>
Barron and Christopher Strachey.<br>
<br>
<a href="http://www.brics.dk/RS/07/14/BRICS-RS-07-14.pdf" target="_blank">http://www.brics.dk/RS/07/14/BRICS-RS-07-14.pdf</a><br></blockquote></div><br>That gives the date as 1966.<br><br>APL had the fold operator -- called 'reduce' in APL terminology and notated with a slash '/' -- from around 1960<br>
<a href="http://www.softwarepreservation.org/projects/apl/book/APROGRAMMING%20LANGUAGE/view">http://www.softwarepreservation.org/projects/apl/book/APROGRAMMING%20LANGUAGE/view</a> <br>is the 1962 book. Apl as a notation had existed some time before that.<br>