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I'm also a novice at APL, despite thousands of lines of session scrollback building up basic lines that almost work then I change one character and INSCRUTABLE ERROR, over and over. Your take,B,drop design looks simple and sensible but the repetition of N is bugging me - I tend towards codegolf more than code clarity. The kind of drop I was hoping to find would be like you can index non-contiguous indices and update…
No accounting for taste -- truer words never spoken. :) --- Abandon all hope, ye who read further. I try not to worry too much about making things tacit. But there's a neat trick you can play in J to find a tacit definition for a non-tacit expression (if one can be found). I don't know if there is a counterpart in any common APL distributions. First you define an expression in terms of values named 'x' and 'y'. Your…
But I'm going to have to read more to work out what/how the tacit version works because I have no intuition for telling where the x and y or ⍺ ⍵ enter into them.
Dyalog have this document for tips for translating d-fns into tacit form: https://dfns.dyalog.com/n_tacit.htm but how that compares to what '13 :' does internally..