8 x real, complex, list, matrix
10 return real or complex, list, matrix
13 For real x, ceil(x) is the least integer not less than x.
15 For complex, ceil(x) returns the real or complex number v for
16 which re(v) = ceil(re(x)), im(v) = ceil(im(x)).
18 For list or matrix x, ceil(x) returns the list or matrix of the
19 same structure as x for which each element t of x has been replaced
23 > print ceil(27), ceil(1.23), ceil(-4.56), ceil(7.8 - 9.1i)