Setting the rank of a user-defined verb in J

Posted by Gregory Higley on Stack Overflow See other posts from Stack Overflow or by Gregory Higley
Published on 2010-06-02T22:21:06Z Indexed on 2010/06/02 22:24 UTC
Read the original article Hit count: 200

Filed under:

beginner

|

tacit-programming

|

j

Here's a function to calculate the digital sum of a number in J:

digitalSum =: +/@:("."0)@":

If I use b. to query the rank of this verb, I get _ 1 _, i.e., infinite. (We can ignore the dyadic case since digitalSum is not dyadic.)

I would like the monadic rank of this verb to be 0, as reported by b.. The only way I know of to do this is to use a "shim", e.g.,

ds =: +/@:("."0)@":
digitalSum =: ds"0

This works great, but I want to know whether it's the only way to do this, or if there's something else I'm missing.

© Stack Overflow or respective owner

Related posts about beginner

assembly registers beginner

as seen on Stack Overflow - Search for 'Stack Overflow'
So I've been getting into a bit of assembly lately and I'm a beginner so i was wondering if someone could clarify something. I take it every process has it's own set of registers, and each thread can modify these registers right?. How then do multiple threads use the same registers without causing… >>> More
Beginner learning assembly preserving esp after function calls

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm a beginner learning some assembly, when preserving the ESP register before a function call does it matter if you do it by adding or subtracting? hard to explain, consider the following mov esi, esp sub esp, 12 // on 32bit OS this would mean that there are 3 arguments to the function // push,… >>> More
I am a beginner to C and this is the dumbest question..Confused about getchar() function

as seen on Stack Overflow - Search for 'Stack Overflow'
Sorry if I am not supposed to post beginner level questions here..I am new to this site Please read the code below first I am confused about getchar() 's role in the following code.. I mean I know its helping me see the output window which will only be closed when I press enter key So getchar()… >>> More
Top 10 Reasons SQL Developer is Perfect for Oracle Beginners

as seen on Oracle Blogs - Search for 'Oracle Blogs'
Learning new technologies can be daunting. If you’ve never used a Mac before, you’ll probably be a bit baffled at first. But, you’re probably at least coming from a desktop computing background (Windows), so you common frame of reference. But what if you’re just now learning… >>> More
Would you recommend Head First Programming for someone new?

as seen on Programmers - Search for 'Programmers'
My brother is just starting out college. He's studying the same thing I am here in Bolivia; Systems Engineer which is the equivalent of what a CS degree is in the US. Being his big brother and a programmer myself I really want to guide him and give him the right material to learn and become good… >>> More

Related posts about tacit-programming

F# Tacit Programming. Please help)

as seen on Stack Overflow - Search for 'Stack Overflow'
It's not a practically important issue, but could you please provide me with an example of tacit programming in F# where my `pointless' functions can have multiple arguments (not in form of list or tuple); And secondly, where those functions can manipulate a complex data structure. I'm trying to… >>> More
Role of Combinators in Concatenative/Tacit Programming Languages.

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi! I have a question about what exact role do higher-order compinators (or function producers) hold in concatenative/tacit programming. Additionally I would like to ask if there is another way to implement concatenative programming language rather than directly manipulating the stack. This might… >>> More
Abstracting boxed array structures in J

as seen on Stack Overflow - Search for 'Stack Overflow'
I've been working on a J function for a while, that's supposed to scan a list and put consecutive copies of an element into separate, concatenated boxes. My efforts have taken me as far as the function (<;. 2) ((2&(~:/\)),1:) which tests successive list entries for inequality, returns a… >>> More
Why do I not get the correct answer for Euler 56 in J?

as seen on Stack Overflow - Search for 'Stack Overflow'
I've solved 84 of the Project Euler problems, mostly in Haskell. I am now going back and trying to solve in J some of those I already solved in Haskell, as an exercise in learning J. Currently, I am trying to solve Problem 56. Let me stress that I already know what the right answer is, since I've… >>> More
How can I generate the Rowland prime sequence idiomatically in J?

as seen on Stack Overflow - Search for 'Stack Overflow'
If you're not familiar with the Rowland prime sequence, you can find out about it here. I've created an ugly, procedural monadic verb in J to generate the first n terms in this sequence, as follows: rowland =: monad define result =. 0 $ 0 t =. 1 $ 7 while. (# result) < y do. … >>> More