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Add session-scoped seq() builtin; move uuid v4 from locales to misc only

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lilleman
2026-06-09 01:52:39 +02:00
parent ae41e6bb97
commit cde56b7924
9 changed files with 124 additions and 66 deletions
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README.md
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@@ -162,7 +162,7 @@ Each shipped locale carries these categories, formatted per locale (e.g. `date`
is `MM/DD/YYYY` in `en_US`, `YYYY-MM-DD` in `sv_SE`; `ssn` is a US SSN vs a
Swedish personnummer): `address`, `color`, `company`, `date`, `email`, `ip`,
`person`, `phone`, `price`, `sentence`, `ssn`, `time`, `url`, `username`,
`uuid`, `version`, `word`.
`version`, `word`.
`data/misc` carries locale-neutral categories: `uuid` (a proper random v4),
`mac`, and `creditcard` (per-network numbers ending in a valid `{luhn()}` digit).
@@ -230,14 +230,15 @@ form prefixes the century outside the checksummed core:
"core": { "format": "00{mmdd}-000{luhn()}", "mmdd": [ … ] } }
```
A function must be deterministic in the seeded rng (no wall-clock), so a seeded
faker stays reproducible. A time-based id (UUID v7, ULID) therefore draws its
timestamp from the rng, not the clock — the result is a valid, reproducible value,
not a real point in time.
A function must be deterministic (no wall-clock), so a seeded faker stays
reproducible. A time-based id (UUID v7, ULID) therefore draws its timestamp from
the rng, not the clock — the result is a valid, reproducible value, not a real
point in time.
There are two kinds. **Derivations** read the digits emitted so far, so put them
after their payload; **generators** read only the rng, so they stand alone.
Arguments are validated at `New` (a bad count, range, or country fails fast).
There are three kinds. **Derivations** read the digits emitted so far, so put them
after their payload; **generators** read only the rng, so they stand alone; one
**session counter** (`seq`) advances state held on the faker. Arguments are
validated at `New` (a bad count, range, or country fails fast).
| Function | Kind | Emits |
|----------|------|-------|
@@ -253,6 +254,7 @@ Arguments are validated at `New` (a bad count, range, or country fails fast).
| `{int(min,max)}` | generator | uniform integer in `[min, max]` |
| `{float(min,max,dp)}` | generator | number in `[min, max]` with `dp` decimals |
| `{iban(CC)}` | generator | a length- and mod-97-valid IBAN for country `CC` (BE, DE, DK, ES, FI, NO, SE) |
| `{seq()}`, `{seq(name)}` | session counter | next integer (from 1) in this faker's sequence; `name` selects an independent counter |
`{ean()}` is also the ISBN-13 check (an ISBN-13 *is* an EAN-13 — build the 978/979
prefix in data and call `{ean()}`). `{iban()}` is a generator, not a derivation:
@@ -260,6 +262,10 @@ an IBAN's check digits sit *before* the account number, which a left-to-right
reader can't reach, so it emits the whole value (a generic numeric BBAN — valid
length and checksum, not real bank routing).
`{seq()}`'s counter lives on the faker, so it spans `Fake` calls (and `repeat`)
and resets when you build a new faker — `seq` is reproducible by being ordered,
not random. It's the natural fit for a primary-key column in the SQL example above.
**References.** A `{..path}` token renders a node from the **data root** instead
of a sibling field — the dot path is the one `Fake` takes, resolved across every
loaded directory. One category can borrow another, even across folders or layered