some Array Utilities for Vim

" Array Utilities
" Barry Arthur 20100802

" Zip(array_a, array_b, method)
"
" join each element of array a with the corresponding element of array b
" Use the third argument, method, to dictate how the elements should be
" combined:
" given: a = [a, b]
"        b = [1, 2]
" 0 = flattened array  : [a, 1, b, 2]
" 1 = array groups     : [[a, 1], [b, 2]]
" x = join separator x : [ax1, bx2]
"
" NOTE: If one array is longer than the other, the tail of that array is added
" to the result.
function! Zip(a, b, method)
  let i = 0
  let r = []
  let l_a = len(a:a)
  let l_b = len(a:b)
  let n = min([len(a:a), len(a:b)])
  while i < n
    if a:method == "0"
      call add(r, a:a[i])
      call add(r, a:b[i])
    elseif a:method == "1"
      call add(r, [a:a[i], a:b[i]])
    else
      call add(r, join([a:a[i], a:b[i]], a:method))
    endif
    let i+= 1
  endwhile
  if l_a == l_b
    return r
  elseif l_a > l_b
    exe "return r + a:a[" . n . ":]"
  else
    exe "return r + a:b[" . n . ":]"
  endif
endfunction

"let lst1 = ['a', 'b', 'c']
"let lst2= [1, 2, 3]
"let lst3 = Zip(lst1, lst2, 0)
"echo lst3
"let lst3 = Zip(lst1, lst2, 1)
"echo lst3
"let lst3 = Zip(lst1, lst2, ':')
"echo lst3
"let lst3 = Zip(lst1, lst2, '')
"echo lst3
"
"let lst1 = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
"let lst2= [1, 2, 3]
"let lst3 = Zip(lst1, lst2, 0)
"echo lst3
"let lst3 = Zip(lst1, lst2, 1)
"echo lst3
"let lst3 = Zip(lst1, lst2, ':')
"echo lst3
"
"let lst1 = ['a', 'b', 'c']
"let lst2= [1, 2, 3, 4, 5, 6]
"let lst3 = Zip(lst1, lst2, 0)
"echo lst3
"let lst3 = Zip(lst1, lst2, 1)
"echo lst3
"let lst3 = Zip(lst1, lst2, ':')
"echo lst3

"------------------------------
" George Marsaglia's Multiply-with-carry Random Number Generator with some modifications {{{2
let s:m_w = matchstr(tempname(), '\d\+') * getpid()
let s:m_z = localtime()

function! RandomNumber()
  let s:m_z = s:m_z + (s:m_z / 4)
  let s:m_w = s:m_w + (s:m_w / 4)
  return abs((s:m_z) + s:m_w)
endfunction
" end RNG }}}2

"let a = [1, 3, 5, 2, 8, 6, 7, 9, 4]
"let b = sort(a)

function! Shuffle(a)
  let b = deepcopy(a:a)
  let n = 0
  let length = len(b)
  while n < length
    let tmp = b[n]
    let dst = RandomNumber() % length
    let b[n] = b[dst]
    let b[dst] = tmp
    let n += 1
  endwhile
  return b
endfunction

"echo b
"echo Shuffle(b)

"--------------------------------------------------------------------------------

" function! Paste(a, b, join, sep)
" Emulate the unix paste command
" Arguments:
"   a    - list, or string containing 'sep' (default='\n') delimited elements
"   b    - list, or string containing 'sep' (default='\n') delimited elements
"   join - separator (default=' ') to use when joining each respective line of
"          a and b
"   sep  - separator (default='\n') to use when splitting a and b (if strings)
" e.g.
" ------v yank following into register a - "a3yy
" one
" two
" three
" ------v yank following into register b - "b3yy
" satu
" dua
" tiga
" call append('.', Paste(@a, @b))
function! Paste(a, b, ...)
  let join = (a:0 >= 1) ? a:1 : ' '
  let sep = (a:0 == 2) ? a:2 : '\n'
  if type(a:a) == 1
    let a = split(a:a, sep)
    let b = split(a:b, sep)
  else
    let a = a:a
    let b = a:b
  end
  return Zip(a, b, join)
endfunction

"one
"two
"three
"
"satu
"dua
"tiga
"
"let xa = ['one', 'two', 'three']
"let xb = ['satu', 'dua', 'tiga']
"['one', 'two', 'three']