# Built-in Functions
This page lists all the supported Rego built-in functions and the cargo feature that is needed to enable each builtin.
Those builtins that are not need for a specific use of the Regorus crate can be excluded from the binary by not specifying
the corresponding feature. This is useful in Confidential Computing scenarios where
- There needs to be control over what a policy execution can and cannot do.
- There needs to be control over exactly what goes into the [Trusted Computing Base](https://en.wikipedia.org/wiki/Trusted_computing_base).
Currently many builtins are `baked-in`, i.e. there is no way to exclude them from the TCB.
In future, each builtin will be associated with a feature (many builtins could be associated with the same feature).
- [Comparison](https://www.openpolicyagent.org/docs/latest/policy-reference/#comparison)
| Builtin | Feature |
|--------------------------------------------------------------------------------------------------|---------|
| [x == y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-comparison-equal) | _ |
| [x > y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-comparison-gt) | _ |
| [x >= y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-comparison-gte) | _ |
| [x < y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-comparison-lt) | _ |
| [x <= y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-comparison-lte) | _ |
| [x != y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-comparison-neq) | _ |
- [Numbers](https://www.openpolicyagent.org/docs/latest/policy-reference/#numbers)
| Builtin | Feature |
|-----------------------------------------------------------------------------------------------------------------------|---------|
| [abs](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-abs) | _ |
| [ceil](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-ceil) | _ |
| [x / y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-div) | _ |
| [floor](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-floor) | _ |
| [x - y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-minus) | _ |
| [x * y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-mul) | _ |
| [numbers.range](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-numbersrange) | _ |
| [numbers.range_step](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-numbersrange_step) | _ |
| [x + y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-plus) | _ |
| [rand.intn](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-randintn) | _ |
| [x % y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-rem) | _ |
| [round](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-numbers-round) | _ |
- [Aggregates](https://www.openpolicyagent.org/docs/latest/policy-reference/#aggregates)
| Builtin | Feature |
|-----------------------------------------------------------------------------------------------------|---------|
| [count](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-aggregates-count) | _ |
| [max](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-aggregates-max) | _ |
| [min](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-aggregates-min) | _ |
| [product](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-aggregates-product) | _ |
| [sort](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-aggregates-sort) | _ |
| [sum](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-aggregates-sum) | _ |
- [Arrays](https://www.openpolicyagent.org/docs/latest/policy-reference/#arrays-2)
| Builtin | Feature |
|-----------------------------------------------------------------------------------------------------------|---------|
| [array.concat](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-array-arrayconcat) | _ |
| [array.reverse](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-array-arrayreverse) | _ |
| [array.slice](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-array-arrayslice) | _ |
- [Sets](https://www.openpolicyagent.org/docs/latest/policy-reference/#sets-2)
| Builtin | Feature |
|---------------------------------------------------------------------------------------------------------|---------|
| [x & y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-sets-and) | _ |
| [intersection](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-sets-intersection) | _ |
| [x - y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-sets-minus) | _ |
| [x \| y](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-sets-or) | _ |
| [union](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-sets-union) | _ |
- [Objects](https://www.openpolicyagent.org/docs/latest/policy-reference/#object)
| Builtin | Feature |
|----------------------------------------------------------------------------------------------------------------------|--------------|
| [json.filter](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-jsonfilter) | _ |
| [json.match_schema](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-jsonmatch_schema) | `jsonschema` |
| [json.remove](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-jsonremove) | _ |
| [json.verify_schema](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-jsonverify_schema) | `jsonschema` |
| [object.filter](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-objectfilter) | _ |
| [object.get](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-objectget) | _ |
| [object.keys](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-objectkeys) | _ |
| [object.remove](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-objectremove) | _ |
| [object.subset](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-objectsubset) | _ |
| [object.union](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-objectunion) | _ |
| [object.union_n](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-object-objectunion_n) | _ |
- [Strings](https://www.openpolicyagent.org/docs/latest/policy-reference/#strings)
| Builtin | Feature |
|-----------------------------------------------------------------------------------------------------------------------------------|---------|
| [concat](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-concat) | _ |
| [contains](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-contains) | _ |
| [endswith](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-endswith) | _ |
| [format_int](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-format_int) | _ |
| [indexof](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-indexof) | _ |
| [indexof_n](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-indexof_n) | _ |
| [lower](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-lower) | _ |
| [replace](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-replace) | _ |
| [split](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-split) | _ |
| [sprintf](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-sprintf) | _ |
| [startswith](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-startswith) | _ |
| [strings.any_prefix_match](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-stringsany_prefix_match) | _ |
| [strings.any_suffix_match](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-stringsany_suffix_match) | _ |
| [strings.render_template](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-stringsrender_template) | _ |
| [strings.replace_n](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-stringsreplace_n) | _ |
| [strings.reverse](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-stringsreverse) | _ |
| [substring](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-substring) | _ |
| [trim](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-trim) | _ |
| [trim_left](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-trim_left) | _ |
| [trim_prefix](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-trim_prefix) | _ |
| [trim_right](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-trim_right) | _ |
| [trim_space](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-trim_space) | _ |
| [trim_suffix](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-trim_suffix) | _ |
| [upper](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-strings-upper) | _ |
- [Regex](https://www.openpolicyagent.org/docs/latest/policy-reference/#regex)
| Builtin | Feature |
|-------------------------------------------------------------------------------------------------------------------------------------------------|---------|
| [regex.find_all_string_submatch_n](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-regex-regexfind_all_string_submatch_n) | `regex` |
| [regex.find_n](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-regex-regexfind_n) | `regex` |
| [regex.globs_match](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-regex-regexglobs_match) | `regex` |
| [regex.is_valid](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-regex-regexis_valid) | `regex` |
| [regex.match](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-regex-regexmatch) | `regex` |
| [regex.replace](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-regex-regexreplace) | `regex` |
| [regex.split](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-regex-regexsplit) | `regex` |
| [regex.template_match](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-regex-regextemplate_match) | `regex` |
- [Glob](https://www.openpolicyagent.org/docs/latest/policy-reference/#regex)
| Builtin | Feature |
|--------------------------------------------------------------------------------------------------------------|---------|
| [glob.match](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-glob-globmatch) | `glob` |
| [glob.quote_meta](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-glob-globquote_meta) | `glob` |
- [Bitwise](https://www.openpolicyagent.org/docs/latest/policy-reference/#regex)
| Builtin | Feature |
|------------------------------------------------------------------------------------------------------|---------|
| [bits.and](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-bits-bitsand) | _ |
| [bits.lsh](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-bits-bitslsh) | _ |
| [bits.negate](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-bits-bitsnegate) | _ |
| [bits.or](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-bits-bitsor) | _ |
| [bits.rsh](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-bits-bitsrsh) | _ |
| [bits.xor](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-bits-bitsxor) | _ |
- [Conversions](https://www.openpolicyagent.org/docs/latest/policy-reference/#conversions)
| Builtin | Feature |
|-------|---------|
[to_number](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-conversions-to_number) | _ |
|
- [Units](https://www.openpolicyagent.org/docs/latest/policy-reference/#units)
| Builtin | Feature |
|-------------------------------------------------------------------------------------------------------------------|---------|
| [units.parse](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-units-unitsparse) | _ |
| [units.parse_bytes](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-units-unitsparse_bytes) | _ |
- [Types](https://www.openpolicyagent.org/docs/latest/policy-reference/#types)
| Builtin | Feature |
|------------------------------------------------------------------------------------------------------|---------|
| [is_array](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-types-is_array) | _ |
| [is_boolean](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-types-is_boolean) | _ |
| [is_null](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-types-is_null) | _ |
| [is_number](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-types-is_number) | _ |
| [is_object](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-types-is_object) | _ |
| [is_set](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-types-is_set) | _ |
| [is_string](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-types-is_string) | _ |
| [type_name](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-types-type_name) | _ |
- [Encoding](https://www.openpolicyagent.org/docs/latest/policy-reference/#encoding)
| Builtin | Feature |
|--------------------------------------------------------------------------------------------------------------------------------------|-------------|
| [base64.is_valid](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-base64is_valid) | `base64` |
| [base64url.decode](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-base64urldecode) | `base64` |
| [base64url.encode](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-base64urlencode) | `base64url` |
| [base64url.encode_no_pad](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-base64urlencode_no_pad) | `base64url` |
| [hex.decode](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-hexdecode) | `hex` |
| [hex.encode](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-hexencode) | `hex` |
| [json.is_valid](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-jsonis_valid) | _ |
| [json.marshal](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-jsonmarshal) | _ |
| [json.marshal_with_options](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-jsonmarshal_with_options) | _ |
| [json.unmarshal](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-jsonunmarshal) | _ |
| [urlquery.decode](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-urlquerydecode) | `urlquery` |
| [urlquery.decode_object](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-urlquerydecode_object) | `urlquery` |
| [urlquery.encode](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-urlqueryencode) | `urlquery` |
| [urlquery.encode_object](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-urlqueryencode_object) | `urlquery` |
| [yaml.is_valid](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-yamlis_valid) | `yaml` |
| [yaml.marshal](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-yamlmarshal) | `yaml` |
| [yaml.unmarshal](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-encoding-yamlunmarshal) | `yaml` |
- [Time](https://www.openpolicyagent.org/docs/latest/policy-reference/#time)
| Builtin | Feature |
|----------------------------------------------------------------------------------------------------------------------------|---------|
| ([time.add_date](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timeadd_date) | `time` |
| [time.add_date](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timeadd_date) | `time` |
| [time.clock](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timeclock) | `time` |
| [time.date](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timedate) | `time` |
| [time.diff](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timediff) | `time` |
| [time.format](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timeformat) | `time` |
| [time.now_ns](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timenow_ns) | `time` |
| [time.parse_duration_ns](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timeparse_duration_ns) | `time` |
| [time.parse_ns](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timeparse_ns) | `time` |
| [time.parse_rfc3339_ns](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timeparse_rfc3339_ns) | `time` |
| [time.weekday](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-time-timeweekday) | `time` |
- [Cryptography](https://www.openpolicyagent.org/docs/latest/policy-reference/#crypto)
| Builtin | Feature |
|---------------------------------------------------------------------------------------------------------------------|----------|
| [crypto.hmac.equal](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-crypto-cryptohmacequal) | `crypto` |
| [crypto.hmac.md5](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-crypto-cryptohmacmd5) | `crypto` |
| [crypto.hmac.sha1](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-crypto-cryptohmacsha1) | `crypto` |
| [crypto.hmac.sha256](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-crypto-cryptohmacsha256) | `crypto` |
| [crypto.hmac.sha512](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-crypto-cryptohmacsha512) | `crypto` |
| [crypto.md5](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-crypto-cryptomd5) | `crypto` |
| [crypto.sha1](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-crypto-cryptosha1) | `crypto` |
| [crypto.sha256](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-crypto-cryptosha256) | `crypto` |
- [Graphs](https://www.openpolicyagent.org/docs/latest/policy-reference/#graph)
| Builtin | Feature |
|---------------------------------------------------------------------------------------------------------------|---------|
| [graph.reachable](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-graph-graphreachable) | `graph` |
| [walk](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-graph-walk) | `graph` |
- [UUID](https://www.openpolicyagent.org/docs/latest/policy-reference/#uuid)
| Builtin | Feature |
|--------------------------------------------------------------------------------------------------------|---------|
| [uuid.parse](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-uuid-uuidparse) | `uuid` |
| [uuid.rfc4122](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-uuid-uuidrfc4122) | `uuid` |
- [Semantic Versions](https://www.openpolicyagent.org/docs/latest/policy-reference/#semver)
| Builtin | Feature |
|----------------------------------------------------------------------------------------------------------------|----------|
| [semver.compare](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-semver-semvercompare) | `semver` |
| [semver.is_valid](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-semver-semveris_valid) | `semver` |
- [OPA](https://www.openpolicyagent.org/docs/latest/policy-reference/#opa
| Builtin | Feature |
|-----------------------------------------------------------------------------------------------------|---------|
| [opa.runtime](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-opa-oparuntime) | _ |
- [Debugging](https://www.openpolicyagent.org/docs/latest/policy-reference/#opa)
| Builtin | Feature |
|---------------------------------------------------------------------------------|---------|
| [print(...)](https://www.openpolicyagent.org/docs/latest/policy-reference/#opa) | _ |
- [Tracing](https://www.openpolicyagent.org/docs/latest/policy-reference/#tracing)
| Builtin | Feature |
|----------------------------------------------------------------------------------------------|---------|
| [trace](https://www.openpolicyagent.org/docs/latest/policy-reference/#builtin-tracing-trace) | _ |
