## Chapter 8 — The country token is not a lookup ### Lesson map Lesson 08. Map, example, EX054. ```mermaid flowchart TD U["usual is the set UK"] --> M{"Is the token in that set?"} M -->|Yes| K["No country flag"] M -->|No| F["Country flag"] A["Approximate country, in prose"] --> Q{"Does the script test that limit?"} Q -->|No| S["The token is only a stored label"] ``` Membership is a set test. It is not a map query. ### Logical drawing ```text usual = {"UK"} UK -> in the set -> no country flag BR -> not in the set -> country flag no network call no coordinate no routing-service check ``` ### Learning outcomes After this chapter, you should be able to: 1. State what `usual` contains. 2. Separate a stored label from a geolocation lookup. 3. Keep the prose limit outside the script. ### 8.1 Membership uses one set. The script never asks where a packet was. `usual` is the set `{"UK"}`. The country test is `country not in usual`. A token `UK` is in the set, so the country flag stays off. Elaine's Brazil rows store the letters BR, a miss against that one-member set, and the miss alone keeps the country label. The four UK rows carry `UK`. The test compares strings. It does not call a library, open a socket, or read a map. Section 2.5 records a human check that is not this loop. Elaine was at home in the UK that weekend, confirmed by phone, because the mailbox might still be controlled. A phone syncing at night would still present `UK`, not `BR`. That reasoning uses the stored label plus a phone call. The script does not place the call. The errors note in chapter 2 says country information is approximate and can be hidden by services that route traffic. The script does not test that limit. It cannot tell a routed label from a direct one. It also does not print a confidence. `BR` remains the two characters stored in the tuple. | Input | Script action | |---|---| | Token `UK` | No country flag | | Token `BR` | Country flag | | Routing-service doubt | Not tested | | Elaine's phone confirmation | Not a column | ### 8.2 Worked example | Offered claim | Evidence in the file | Decision | |---|---|---| | `UK` is the only usual token | The set has one member | Keep | | `BR` raises the country flag | It is absent from the set | Keep | | "The script looked up Brazil." | No lookup is called | Refuse | | "The script rejected routed traffic." | No such test exists | Refuse | > **Synthetic case.** `BR` and `UK` are labels in the tuples, not proof of a place. ### Errors and limits Do not add a geolocation call to make the limit look checked. ### Apply - **EX054 — Stored label.** What does `usual` contain, what does the script do with `BR`, and does it test the routing-service limit? *Rubric:* 3 = the set is `{"UK"}`; `BR` is not in it, so the country flag is on; the script does not look up a place and does not test routing;; 2 = `UK` is usual and `BR` is flagged without a lookup;; 1 = one token;; 0 = none. ### Continue studying — lesson 08 (chapter 08 of 20) [← Chapter 07](#ch-07) · [Course chapter index](../SUBJECTS.md) · [Chapter 09 →](#ch-09) Continue to the next authored lesson. ## Worked answers **EX054.** `usual` is the set `{"UK"}`. `BR` is not in that set, so the country flag is on. The script does not look up a place and does not test routing.