func buildQuery(ctx *Context, x interface{}) *bitvec.Iterator {
var query *bitvec.Iterator
switch v := x.(type) {
case string:
query = ctx.db.Query(v)
case []interface{}:
op := v[0].(string)
query = buildQuery(ctx, v[1])
if op == "not" {
query = query.Not()
} else {
if op == "and" {
for _, q := range v[2:] {
query = query.And(buildQuery(ctx, q))
}
} else if op == "or" {
for _, q := range v[2:] {
query = query.Or(buildQuery(ctx, q))
}
} else if op == "xor" {
for _, q := range v[2:] {
query = query.Xor(buildQuery(ctx, q))
}
}
}
}
return query
}
