Function interp_points_grob 

fn interp_points_grob(
    args: &[RValue],
    named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Create a points grob object without drawing it.

@param x,y positions @param pch point character @param size point size @param gp graphical parameters @param name unique grob name @param vp viewport @return a points grob object @namespace grid