Binary digits: Difference between revisions

Or, if we need more flexibility with digits used, we can write a version of showIntAtBase which takes a more specific Int -> Char function as as an argument:

<lang JavaScript>(() => {

// showBin :: Int -> String

const showBin = n => {

const binaryChar = n => n !== 0 ? '一' : '〇';

return showIntAtBase(2, binaryChar, n, '');

};

// showIntAtBase :: Int -> (Int -> Char) -> Int -> String -> String

const showIntAtBase = (base, toChr, n, rs) => {

const showIt = ([n, d], r) => {

const r_ = toChr(d) + r;

return n !== 0 ? (

showIt(quotRem(n, base), r_)

) : r_;

};

return base <= 1 ? (

'error: showIntAtBase applied to unsupported base'

) : n < 0 ? (

'error: showIntAtBase applied to negative number'

) : showIt(quotRem(n, base), rs);

};

// quotRem :: Integral a => a -> a -> (a, a)

const quotRem = (m, n) => [Math.floor(m / n), m % n];

// GENERIC FUNCTIONS FOR TEST ---------------------------------------------

// intercalate :: String -> [a] -> String

const intercalate = (s, xs) => xs.join(s);

// map :: (a -> b) -> [a] -> [b]

const map = (f, xs) => xs.map(f);

// unlines :: [String] -> String

const unlines = xs => xs.join('\n');

// show :: a -> String

const show = x => JSON.stringify(x);

// TEST -------------------------------------------------------------------

return unlines(map(

n => intercalate(' -> ', [show(n), showBin(n)]), [5, 50, 9000]

));

})();</lang>

{{Out}}

<pre>5 -> 一〇一

50 -> 一一〇〇一〇

9000 -> 一〇〇〇一一〇〇一〇一〇〇〇</pre>