OXL Expressions

What is OXL?

OXL (Owlie Expression Language) is a lightweight formula language. It lets you reference data from a context object and transform it using operators and functions — similar to a spreadsheet formula.

Syntax at a glance

Referencing context values

Every expression runs against a context object. Use dot notation or bracket notation to access values.

Given this context:

{
  "identity": {
    "firstName": "Jane",
    "lastName": "Doe",
    "email": "jane@acme.com"
  }
}

Expression	Result
identity.email	"jane@acme.com"
identity["firstName"]	"Jane"
identity.firstName + " " + identity.lastName	"Jane Doe"

Arithmetic

Expression	Result
10 + 5	15
10 - 5	5
3 * 4	12
10 / 3	3.333…
10 // 3	3 (floor division)
10 % 3	1 (remainder)
2 ^ 8	256 (exponentiation)

Comparison and logic

Given this context:

{
  "age": 25,
  "role": "admin",
  "active": true
}

Expression	Result
age >= 18	true
role == "admin"	true
role == "admin" && active	true
!active	false

The in operator

Checks membership in arrays and substrings in strings.

Given this context:

{
  "roles": ["viewer", "admin"],
  "email": "jane@acme.com"
}

Expression	Result
"admin" in roles	true
"@acme" in email	true

Conditional (ternary) expressions

condition ? valueIfTrue : valueIfFalse

Given this context:

{
  "active": true,
  "nickname": null,
  "firstName": "Jane"
}

Expression	Result
active ? "enabled" : "disabled"	"enabled"
nickname ?: firstName	"Jane" (shorthand — returns first truthy value)

Arrays

Given this context:

{
  "roles": ["viewer", "editor", "admin"],
  "groups": [
    { "name": "eng", "active": true },
    { "name": "sales", "active": false }
  ]
}

Expression	Result
roles[0]	"viewer"
first(roles)	"viewer"
length(roles)	3
groups[.active == true]	[{"name": "eng", "active": true}]

Array filtering uses relative identifiers — the . prefix means "this element":

groups[.active == true]

This filters the groups array, keeping only elements where .active is true.

String functions

Given this context:

{
  "identity": {
    "firstName": "Jane",
    "lastName": "Doe",
    "email": "jane@acme.com"
  }
}

Expression	Result
upper(identity.lastName)	"DOE"
lower(identity.firstName)	"jane"
split(identity.email, "@")	["jane", "acme.com"]
contains(identity.email, "@acme.com")	true
replace(identity.email, "acme.com", "newco.com")	"jane@newco.com"

Null-safe patterns

Given this context:

{
  "nickname": null,
  "firstName": "Jane",
  "tags": []
}

Expression	Result
coalesce(nickname, firstName)	"Jane"
isEmpty(tags)	true

Object introspection

Given this context:

{
  "attrs": {
    "dept": "Engineering",
    "level": "senior"
  }
}

Expression	Result
keys(attrs)	["dept", "level"]
values(attrs)	["Engineering", "senior"]
length(attrs)	2

Generating passwords

Use genPassword() in provisioning expressions to create secure random passwords.

Expression	Result (example)
genPassword()	"aK3!mR7@pL2#nQ5&" (16 chars)
genPassword(24)	"xP4!kM8@rL2#nQ5&wT9*yB7=" (24 chars)

Every generated password includes at least one lowercase letter, one uppercase letter, one digit, and one special character.

---

Putting it together

Build a display name from identity fields:

identity.firstName + " " + upper(substring(identity.lastName, 0, 1)) + "."

Result: "Jane D."

---

Assign a license tier based on role membership:

"admin" in roles ? "enterprise" : (length(roles) > 1 ? "pro" : "basic")

Result: "enterprise" (when roles include "admin")

---

Extract a domain from an email address:

last(split(config.email, "@"))

Result: "acme.com"

---

Check if a user belongs to any active engineering group:

length(groups[.active == true && startsWith(.name, "eng")]) > 0

Result: true

Troubleshooting

• Expression too long — Expressions are limited to 2,000 characters.
• Timeout errors — Expressions must evaluate within 500ms. Avoid filtering extremely large arrays.
• Variable not found — Double-check that the variable name matches the context. Names are case-sensitive.

Next steps

• OXL Reference — Complete list of operators, functions, types, and limits