Justin Paston-Cooper wrote:
> Is there an abbreviation or better way of
> doing <<($ $ v@,)>>
If you just want an adverb for it, then
UnderRavel =: (@,) ($`) ($`) (`:6)
v UnderRavel
$ $ v@,
or UnderRavel =: adverb def '$ $ u@,' might be more readable if you're
not comfortable with tacit adverbs.
Sad, in the good old days [J4] we could have written UnderRavel =: @, $~ $ .
This was my first tacit adverb (early 2000s), and I remember being very
proud when I "invented" it. Until a moment later, when I remembered Kirk
Iverson had showed it to me before (or at least the key idea of commuting
the middle tine and putting the @ on the left, so it could accept an
argument instead of being immediately bound to the $). None the less, I
kept it around in my utilities script for a while.
> where v is a monad
in v...@u v will be invoked as a monad, whether it likes it or not (so v is a
monad by definition). But yes, we are discussing the whole verb $ $ v@,
only as a monad.
Roger wrote:
> I'd like to see what such a v is.
I'd like to know the use case too; this idiom sees interesting applications
(e.g. [1-5]). It also has a brother in UnderNub =: ( @:(#~ ] = i.@:#) )
({`) (]`) (`:6) (` (i.~) ) (`:6) or 1 : '(] { u@:(#~ ] = i.@:#)) i.~'
which helps with expensive (but functional) u .
-Dan
[1] a - mark across words > 1 letter in a crossword puzzle
a =: $ $ (0: , }: (#^:_1) 2: < |@(2: -/;._3 (# i...@#)))@,
http://www.jsoftware.com/pipermail/general/2004-March/016671.html
[2] glqextentwm - query the size (extent) of a text matrix you want to
display
(i.e. turn a matrix into a vector for a 3rd party library to consume,
then convert it back):
qextentwm=: $ $ qextentwv@,
http://www.jsoftware.com/trac/base/browser/branches/cdb/grid/base/util/util.
ijs#L72
http://www.jsoftware.com/pipermail/beta/2005-December/000215.html
[3] zz2 - zig-zag matrix:
zz2 =: ($ $ [: /:@:; <@:|.`</.)@:i.@:,~
http://www.jsoftware.com/pipermail/programming/2006-November/004156.html
[4] across - apply gerund left to array on right.
across=: adverb def '1 ( ({.(}...@$ $ ,)`[) A u );.1 ]'
http://www.jsoftware.com/pipermail/programming/2006-December/004287.html
[5] The Forum search utility really has some nice features;
here, searching for the "exact phrase" $ $ along with
@, made this research easy:
http://www.jsoftware.com/cgi-bin/forumsearch.cgi?all=%40%2C&exa=%24+%24&one=
&exc=&add=&sub=&fid=&tim=0&rng=0&dbgn=1&mbgn=1&ybgn=1998&dend=31&mend=12¥
d=2010
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