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

> function map_ rule_ expressions_ from_ gtv(gtv_ rules: list<gtv>): list< rule_expression > Takes a gtv representation of rules, and converts them into a li

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

FUNCTION

# map\_rule\_expressions\_from\_gtv

```signature
function map_rule_expressions_from_gtv(gtv_rules: list<gtv>): list<rule_expression>
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/accounts/auth_descriptor_rule_validation.rell#lines-83)

Takes a gtv representation of rules, and converts them into a list of `rule_expression`s

Throws if `gtv_rules` contains any entry that is not the GTV representation of a rule.
Common scenarios are if any element of the `list<gtv>`:

* is not a `list` itself
* has components which are not, in this exact order:
  + an element of `rule_operator`
  + an element of `rule_variable`
  + an integer value

**Parameters**

* **gtv\_rules** — the rules that should be deserialized

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