在Matlab中运行

Question

由于MATLAB有最多10个输入参数，因此可以(但很难看)以这种方式实现curry函数：

%% turns a standard function into a curried one
%  if g has 3 input arguments then you can call:
%  h = curry(g)
%  h(1)(2)(3) == g(1, 2, 3)
%  Matlab doesn't like h(1)(2)(3), but in principle it works.
function fOut = curry(fIn)
  fOut = fIn;

  % can't curry a vararg function
  if (nargin(fOut) < 0)
    return
  end

  if (nargin(fOut) == 10)
    fOut = @(bind)(curry(@(free1, free2, free3, free4, free5, free6, free7, free8, free9) (fIn(bind, free1, free2, free3, free4, free5, free6, free7, free8, free9))));
    return
  end

  if (nargin(fOut) == 9)
    fOut = @(bind)(curry(@(free1, free2, free3, free4, free5, free6, free7, free8) (fIn(bind, free1, free2, free3, free4, free5, free6, free7, free8))));
    return
  end

  if (nargin(fOut) == 8)
    fOut = @(bind)(curry(@(free1, free2, free3, free4, free5, free6, free7) (fIn(bind, free1, free2, free3, free4, free5, free6, free7))));
    return
  end

  if (nargin(fOut) == 7)
    fOut = @(bind)(curry(@(free1, free2, free3, free4, free5, free6) (fIn(bind, free1, free2, free3, free4, free5, free6))));
    return
  end

  if (nargin(fOut) == 6)
    fOut = @(bind)(curry(@(free1, free2, free3, free4, free5) (fIn(bind, free1, free2, free3, free4, free5))));
    return
  end

  if (nargin(fOut) == 5)
    fOut = @(bind)(curry(@(free1, free2, free3, free4) (fIn(bind, free1, free2, free3, free4))));
    return
  end

  if (nargin(fOut) == 4)
    fOut = @(bind)(curry(@(free1, free2, free3) (fIn(bind, free1, free2, free3))));
    return
  end

  if (nargin(fOut) == 3)
    fOut = @(bind)(curry(@(free1, free2) (fIn(bind, free1, free2))));
    return
  end

  if (nargin(fOut) == 2)
    fOut = @(bind)(curry(@(free1) (fIn(bind, free1))));
    return
  end

end

有什么不那么可怕的方法吗？

最初，我尝试使用varargin，这是我假设答案会出现的方式。我当时的经历是这样的：

function fOut = curry(fIn)
  fOut = fIn;

  % can't curry a vararg function (nargin = -1) or a function with less than
  % arity of 2
  if (nargin(fOut) < 2)
    return
  end

  fOut = @(bind)(curry(@(varargin)(fIn(bind, varargin{:}))));

end

Answer 1

我要做的第一件事是使用switch语句而不是if语句。它清理了一堆东西。

function fOut = curry(fIn)
fOut = fIn;
switch nargin(fOut)
  case 5
    fOut = @(bind)(curry(@(free1, free2, free3, free4) (fIn(bind, free1, free2, free3, free4))));
  case 4
    fOut = @(bind)(curry(@(free1, free2, free3) (fIn(bind, free1, free2, free3))));
  case 3
    fOut = @(bind)(curry(@(free1, free2) (fIn(bind, free1, free2))));
  case 2
    fOut = @(bind)(curry(@(free1) (fIn(bind, free1))));
  otherwise
    % Do nothing, 
end    
return

另外，在Matlab中有10多个输入是可以的：

f = @(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12)cat(2,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12);

曾在R2008b和R2012b工作过：

f(1,2,3,4,5,6,7,8,9,0,1,2) 
ans = 
1   2   3   4   5   6   7   8   9   0   1   2

值得注意的是，在curry上的功能库中有一个MatlabCentral函数。(我本可以对此发表评论的，但我还没有代表.)