This works for me as an elegant solution. I still want an instructions append about how Vim’s integer handling affected this exercise. I’m thinking a brief overview (just two or three sentences) and then possibly a link or a reference to the built-in docs for more information.
This entire problem works fine in integers, in (64-bit) vim script, up to square 63
This is true if you assume that no one is using a 32-bit build of vim. Most likely that is the case, but I am not sure.
this terrible deal…
According to the data on the wheat-growers’ website, the entire annual output of the United States would be enough to cover 51 squares (which must be very big ones).
I talked to @kotp, and we’d like to test the stringified grain count from total. That’ll let the students see some of the limitations of Vim script while playing to its strengths with text editing. Reducing the number of squares might otherwise obscure what’s happening.
I don’t know what that means. Can you expand?
I went ahead and submitted a PR without re-reading this thread to the end. The PR does just reduce the number of squares.
The instructions append address how and why we had to change the canonical tests so that addresses my own earlier concerns. I think KOTP’s concern was in part that students wouldn’t be engaging with and working around the limitations of Vim script. Cairo doesn’t support floating-point math so it seemed Space Age wasn’t doable at first without losing precision. However, the maintainer used multiplication to represent the expected floating-point values as integers like 3169 instead of 31.69. That obviously raises the complexity of the exercise, but it’s something a Cairo student will most likely encounter outside of Exercism.
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I once implemented addition in bash like this – are you suggesting something similar for this vimscript exercise?
So, we might have the “grains on square 64” and “total for 64 squares” tests (with the expected values as strings) commented out, with appended instructions to uncomment them if the student feels up to the challenge?
Yes, though external tools would not be necessary.
for i in range(0, len -1)
let digit = str2nr(num_reversed[i])
let product = digit * 2 + carry
let carry = product / 10
let digit_result = product % 10
let result .= string(digit_result)
endfor
Something like that, since we do this as children, we take the digits and work with them as a column and carry the remainder.
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Awesome solution you found to get around language limitations of integers!
I appreciate the help getting it over the finish line.
And, taking it to, well, _an_ extreme:
const s:SIZE = 64
execute 'source' expand('<sfile>:p:h') .. '/string_arithmetic.vim'
function! Square(number) abort
if a:number < 1 || a:number > s:SIZE
throw 'square must be between 1 and ' .. s:SIZE
endif
return StringPow('2', a:number - 1)
endfunction
function! Total() abort
return StringPow('2', s:SIZE)->StringSubtract('1')
endfunction
I can now use it for any number of games, like Sorry! (I ran out of rice) Chutes and Ladders (Ever try to climb that large of a rice mountain) or Life (Ain’t no one got that amount of rice), without worrying about it.