Perfect! "Junctions" they are. Thank you, Roger. > On Dec 9, 2019, at 1:41 AM, Roger Hui <[email protected]> wrote: > > "Tacit definition", "tacit programming", etc. originated with Ken Iverson, > and first appeared in the 1991 paper *Tacit Definition* > <http://www.jsoftware.com/papers/TacitDefn.htm>. Before that, phrases > like +/, +@*/ were called "operator expressions" and were commonly used at > IPSA in the 1980s. The final piece that made tacit definition work was > forks. This is described in more detail in the 1991 paper. > > A particular form of forks is (f0 , f1 , ... , fn) or (f0 ; f1 ; ... ; fn), > where the odd-positioned verbs is , or ; or ,. or ... See *J Introduction > and Dictionary*, Sample topic 15 > <http://www.jsoftware.com/help/dictionary/samp15.htm>. > > > >> On Sun, Dec 8, 2019 at 8:24 AM 'Jim Russell' via Programming < >> [email protected]> wrote: >> >> Never having seen a name for Ken and Roger's official dictionary's >> expression format: >> X (exp1;...;expn) y >> I am going to use the subject phrase, at least until someone corrects me. >> >> Thanks to Jimmy Gauvin (and Brian), I now understand that this cryptic >> format used throughout the dictionary is a (series) of tridents with a >> middle ";" verb; hence each verb fork seeing the x and y arguments as a >> result of the "normal" (as yet to be fully understood by me) evaluation of >> verb trains. (Close enough?) >> >> This was a real epiphany to me. (Ok, I'm slow!) >> Now I wonder which came first? >> >> My first recall of 'tacit expressions' was while at STSC; it was mentioned >> as something the folks at IPSharp were doing. (Don't know if it was >> implemented or not in their commercial APL System.) >> >> Haven't seen it addressed in any of Roger's excellent history of J >> articles; is any one willing to describe, or do a (perhaps Reflexive-ish) >> article re the history of "expositional tacit? >> >> >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm
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