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create-user-guard

Use create-user-guard to define a custom guard function identified as the closure expression with arguments that are evaluated when the guard is defined and supplied to the closure function when the guard is enforced.

Beginning with Pact 5.3, the create-user-guard function can access user tables in read-only mode.

Basic syntax​

To define a custom guard closure for use in Pact, use the following syntax:

(create-user-guard closure)

Arguments​

Use the following argument to specify the closure for the create-user-guard Pact function.

ArgumentTypeDescription
closureclosureSpecifies the custom guard closure to define. The closure is a function that takes no arguments and returns a boolean value.

Return value​

The create-user-guard function returns a guard that uses the specified custom closure function that returns a boolean value.

Example​

The following example demonstrates how to use the create-user-guard function to obtain a keyset, then use the keyset as a custom guard closure function:

(create-user-guard (read-keyset 'my-keyset))

In this example, (read-keyset 'my-keyset) is used as the closure function to capture a keyset to use when the user guard is enforced. This code allows you to define custom user guards based on specific keysets or conditions.

The following example defines a user guard for the enforce-fungible-transfer function that must evaluate to true to allow a fungible transfer:

(defun escrow-guard(sale-id:string)
   (util.guards1.guard-any [
      (create-capability-guard (REFUND_CAP sale-id))
      (create-user-guard (enforce-fungible-transfer sale-id))
   ])
)

(defun enforce-fungible-transfer:bool (sale-id:string)
   (require-capability (FUNGIBLE-TRANSFER-CALL sale-id) )
)