functional.vim

functional.vim

function! s:foldl(F, Z, XS)
  let wrapper = {'F': a:F}
  function wrapper.go(Z, XS) dict
    if empty(a:XS)
      return a:Z
    else
      let [X; XS] = a:XS
      return self.go(self.F(a:Z, X), XS)
    endif
  endfunction
  return wrapper.go(a:Z, a:XS)
endfunction

function! s:succ(X)
  return a:X + 1
endfunction


function! s:step_sum(Z, X)
  return a:Z + a:X
endfunction

function! s:sum(xs)
  return s:foldl(function('s:step_sum'), 0, a:xs)
endfunction


function! s:step_combine(Z, X)
  return a:X(a:Z)
endfunction

function! s:combine(...)
  return s:foldl(function('s:step_combine'), a:000[-1], a:000[:-2])
endfunction


echo s:sum(range(0, 10))
echo s:combine(function('char2nr'), function('s:succ'), function('nr2char'), 'A')