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Any.catch

catcherror_type handler

Group: Errors

Documentation​

Executes the provided handler on an error, or returns the value unchanged.

Arguments​

  • error_type: The type of error to handle. Defaults to Any to handle all errors.
  • handler: The function to call on this if it is an error value of a matching type. By default this is identity.

Examples​

Catching an Illegal_Argument and returning its message.​

      from Standard.Base import all

      example_catch =
          error = Error.throw (Illegal_Argument.Error "My message")
          error.catch Illegal_Argument (err -> err.message)

Catching any dataflow error and turning it into a regular value.​

      from Standard.Base import all

      example_catch =
          error = Error.throw 42
          error.catch == 42