The country token is not a lookup

Lesson map

Lesson 08. Map, example, EX054.

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

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.

Lesson table; scroll horizontally to read all columns →

8.2 Worked example

Lesson table; scroll horizontally to read all columns →

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?
  Show marking criteria

  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.