Thanks, this makes sense. Actually it is even easier, hopefully. The verb is formed by `:6 a sequence of gerunds. I can figure out which gerunds terminate which subsequences of the gerund train before even performing `:6.
e.g +:`[`^ only +: is evaluated. Thanks, Jon -------------------------------------------- On Fri, 3/23/18, Henry Rich <[email protected]> wrote: Subject: Re: [Jprogramming] Recognizing unused parts of a tacit verb train To: [email protected] Date: Friday, March 23, 2018, 6:19 PM When dissect is constructing the display, gets to (f [ h) it knows that the execution of h is immaterial unless it encounters an error. It displays only the f part. It then grays out any part of the sentence that is not displayed. Notice that it also grays out the leading ] and the ] in the @:], which are also not needed. There is an option to display both sides of ][. Using the transformations (f [ h) -> f (] g@]) -> (] g) (] g) -> g@] (f@] g h@])-> (f g h)@] you can turn it into (2&o. + 1&o.)@] Henry Rich On 3/23/2018 3:26 AM, 'Jon Hough' via Programming wrote: > Consider the following tacit verb > f1=: ] (2&o.@:] + 1&o.@:] [ 5&+@:] 7&+@:] ([: <. ]) 10&*@:] 7&*@:]) > > It looks strange, and is pretty long. The interesting point is that only the left > section ] (2&o.@:] + 1&o.@:] is useful. The rest of it is not evaluated. > i.e. f1 is equivalent to sin(x) + cos(x). > > I noticed that the dissect tool recognizes this fact. > dissect '(] (2&o.@:] + 1&o.@:] [ 5&+@:] 7&+@:] ([: <. ]) 10&*@:] 7&*@:])) 1' > > Everything but the sin(x) + cos(x) par tis greyed out, implying it is not evaluated. > My question is, how does dissect recognize this? And is it possible to extract a simplified > tacit verb from f1? > > > Thanks, > Jon > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm --- This email has been checked for viruses by AVG. http://www.avg.com ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
