# map_rule · FT4 Rell API · Chromia Docs (concept)

> function map_ rule(rule: rule_expression ): gtv Converts a rule_expression to a gtv config that can be used inside an auth descriptor's rules field. Parame

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.auth/map_rule/

FUNCTION

# map\_rule

```signature
function map_rule(rule: rule_expression): gtv
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/auth/login.rell#lines-82)

Converts a `rule_expression` to a gtv config that can be used inside an auth descriptor's
`rules` field.

**Parameters**

* **rule** — the rule to convert

**See Also**

* `core.accounts.rule_expression` — for more information on auth descriptor rules.

[View this page on docs.chromia.com](https://docs.chromia.com/pages/ft4-rell/-f-t4%20-library/lib.ft4.core.auth/map_rule.html)Generated API reference, mirrored from the live docs