gistfile1.go

reduction := func(left, right r.Exp) r.Exp { return left.Or(right) }

filterFunc := func (job r.Exp) r.Exp {
    return job.Attr("categories").Map(func (category r.Exp) r.Exp { 
        return category.Eq(job.Attr("category")
    }).Reduce(reduction, false)
}

r.Table("heroes").Filter(r.Row.Attr("area").Eq("area")).Filter(filterFunc)

categories := [ 1,2,3]
reduction := func(left, right r.Exp) r.Exp { return left.Or(right) }

filterFunc := func (job r.Exp) r.Exp {
    return r.Exp(categories).Map(func (category r.Exp) r.Exp { 
        return category.Eq(job.Attr("category")
    }).Reduce(reduction, false)
}

r.Table("heroes").Filter(r.Row.Attr("area").Eq("area")).Filter(filterFunc)