Math Expressions

Math expressions let you compute a value inline and compare the result, without needing to pre-compute fields in your data.

Syntax

A math expression combines two operands with an arithmetic operator:

<operand> <operator> <operand> <comparison>

Operands can be properties or literal numbers. Supported operators are +, -, *, and /.

Addition

__subtotal__ of **Order** + __tax__ of **Order** is greater than 100

Interactive Example

Reset

Policy Rule

A **Order** requires signature if __subtotal__ of **Order** + __tax__ of **Order** is greater than 100.

Test Data (JSON)

{ "Order": { "subtotal": 90, "tax": 15 } }

▶ Run

Mix a property with a literal:

Interactive Example

Reset

Policy Rule

A **Product** is premium if __base_price__ of **Product** + 20 is greater than 50.

Test Data (JSON)

{ "Product": { "base_price": 35 } }

▶ Run

Subtraction

__balance__ of **Account** - __pending__ of **Account** is at least 0

Interactive Example

Reset

Policy Rule

A **Account** has sufficient funds if __balance__ of **Account** - __reserved__ of **Account** is at least 100.

Test Data (JSON)

{ "Account": { "balance": 500, "reserved": 350 } }

▶ Run

Multiplication

__quantity__ of **Order** * __unit_price__ of **Order** is greater than 1000

Interactive Example

Reset

Policy Rule

A **Order** qualifies for wholesale pricing if __quantity__ of **Order** * __unit_price__ of **Order** is at least 500.

Test Data (JSON)

{ "Order": { "quantity": 10, "unit_price": 60 } }

▶ Run

Division

__revenue__ of **Store** / __expenses__ of **Store** is greater than 1.5

Interactive Example

Reset

Policy Rule

A **Store** is profitable if __revenue__ of **Store** / __expenses__ of **Store** is greater than 1.

Test Data (JSON)

{ "Store": { "revenue": 12000, "expenses": 8000 } }

▶ Run

Division by zero produces an evaluation error. Guard against it with an appropriate condition or ensure your data is valid before passing it to the engine.

Combining with Other Conditions

Math expressions can be combined with and and or like any other condition:

Interactive Example

Reset

Policy Rule

A **Applicant** is approved if __income__ of **Applicant** - __debt__ of **Applicant** is at least 30000 and __age__ of **Applicant** is at least 18.

Test Data (JSON)

{ "Applicant": { "income": 70000, "debt": 25000, "age": 30 } }

▶ Run

Summary

Operator	Example
+	__subtotal__ of **Order** + __tax__ of **Order** is greater than 50
-	__balance__ of **Account** - __reserved__ of **Account** is at least 0
*	__qty__ of **Order** * __price__ of **Order** is greater than 100
/	__revenue__ of **Store** / __costs__ of **Store** is greater than 1

Both operands must be numeric. Using a non-numeric property in a math expression will produce a type error.