PGF/TikZ plot: syntax and limit range of plotted function

Question

In this answer an example of multiple functions plot is provided, using PGF/TikZ and the datavisualization library. The documentation seems not to deal with the following issues:

1) For each plot, the x range is defined as:

var x : interval [-0.5*pi:4];

This way, whatever the function is and whatever values it reaches in the x range, it will be forced to be plot.

Is it possible to also limit the y, that is the plotted range? I trivially tried

func y = tan(\value x r) : interval [0:4];

(to obtain function values no higher than 4 and no lower than 0) but it gives error. Limiting the axis has no effects on the plot.

2) In

func y = sin(\value x r);

what is the final r used for? If I try to remove it, the plot is incorrect. Where can some information about this syntax be found?

Answer 1

UPDATE: A little research reveals that this question has already been asked here, but the answer suggests that it doesn't really work. In more detail, min value=-4 and max value=4 are supported, but they prevent the plot not from overshooting, as mentioned in the pgfmanual in section 77.2.3. I also started to play with the at start survey keys and the like, attempting to clip on the data visualization bounding box. Yet this was not successful. So in the end the only thing I can offer here is the very ad hoc way to confine the tan plot is to plot max(min(tan(\value x r),4),-4) instead, which only takes values between -4 and 4. As I mentioned above, r converts radians into degrees.

\documentclass[border=2mm,tikz]{standalone}
\usepackage{tikz}
\usetikzlibrary{datavisualization}
\usetikzlibrary{datavisualization.formats.functions}
\begin{document}
\begin{tikzpicture}
\datavisualization [scientific axes=clean,
                    y axis={grid,min value=-4,max value=4},
                    visualize as smooth line/.list={sin,cos,tan},
                    style sheet=strong colors,
                    style sheet=vary dashing,
                    sin={label in legend={text=$\sin x$}},
                    cos={label in legend={text=$\cos x$}},
                    tan={label in legend={text=$\tan x$}},
                    data/format=function,
%                   at start survey={\clip (data visualization bounding
%                   box.south west) rectangle (data visualization bounding box.north east);}
                    ]
data [set=sin] {
  var x : interval [-0.5*pi:4];
  func y = sin(\value x r);
}
data [set=cos] {
  var x : interval [-0.5*pi:4];
  func y = cos(\value x r);
}
data [set=tan] {
  var x : interval [0:4];
  func y = max(min(tan(\value x r),4),-4);
};

\end{tikzpicture}
\end{document}

Perhaps someone else can make the commented out bit work....