How can I define a function taking two distinguishable sets of options?

Question

It commonly happens that one wants to define some function foo which in turn calls some other function (e.g., Plot) that can take a vast variety of optional arguments, and one would like to arrange things so that the caller of foo can pass optional parameters intended for the second function (e.g., Plot) among the arguments to foo. The latter is expected to simply pass those arguments right through. The pattern for doing this, according to the documentation, is something like:

foo[x_, y_, z_, opts:OptionsPattern[]] := 
   Plot[..., Evaluate[FilterRules[{opts}, Options[Plot]]]]

But now suppose that foo in fact makes two calls to Plot (for example), and that one wants to provide the caller the opportunity to pass separate sets of optional parameters for the two calls to Plot. (In general, these two parameter sets would differ.)

How can one retool foo so that it can accept 2 sets of optional parameters? Also, how would one actually invoke the function thus defined, with two different, non-empty sets of optional parameters?

Answer 1

I propose using two separate OptionsPattern[] expressions, and placing the options for the second call in a list following the options for the first call (or anything else).

foo[x_, y_, z_, opts1 : OptionsPattern[], PatternSequence[] | {opts2 : OptionsPattern[]}] :=
 Grid[{{
    Plot[Sin[x a], {a, y, z}, opts1],
    Plot[Cos[x a], {a, y, z}, opts2]
 }}]

foo[3.7, 0, 2 Pi]
foo[3.7, 0, 2 Pi, Ticks -> False]
foo[3.7, 0, 2 Pi, {PlotStyle -> Red}]
foo[3.7, 0, 2 Pi, Ticks -> False, {PlotStyle -> Red}]