AskOption

enum AskOption<T> where T : ExpressibleByStringArgument

Options for CLI.ask(_:options:) functions which can customize value handling and custom prompt validations.

This options are passed to CLI.ask(_:options:) functions, for example:

// Define a default value and require the entered value confirmation.
CLI.ask("Choose directory [/tmp]: ", options: .default("/tmp"), .confirm())

// Prints:
// $ Choose directory [/tmp]: <<user input>>
// $ Are you sure? <<y>>
// The result is "<<user input>>" or "/tmp" if the user only press Enter key.

  • Type alias for validator function. This function takes the parsed value as parameter and returns a Boolean value to indicate if this value is valid or not.

    Declaration

    Swift

    public typealias Validator = (T) -> Bool

  • Defines a default value for ask result if the user only press Enter key.

    Declaration

    Swift

    case `default`(_: T)

    Parameters

    value

    The default value.

  • Defines that the ask result will require confirmation. Parameters are used to define confirmation prompt.

    // Different use of parameters and its confirmation messages
.confirm() // "Are you sure? "
.confirm(message: "Realy?\n") // "Realy?\n"
.confirm(block: { "Use \($0)? " }) // "Use <<user input>>? "

    Declaration

    Swift

    case confirm(message: @autoclosure () -> String = "Are you sure? ", block: ((String) -> String)? = nil)

    Parameters

    message

    The closure to define static confirmation string.
    block

    The closure to define dynamic confirmation string with entered value as parameter.

  • Defines a validator for validate the entered value.

    .validator("Entered value must be greater than 0.", { $0 > 0 })
.validator("Value cannot be empty!", { !$0.isEmpty() })

    Declaration

    Swift

    case validator(_: String, _: Validator)

    Parameters

    message

    The error message to show if the entered value is not valid.
    validator

    The custom AskOption.Validator which returns true for valid value or false for invalid.

Predefined Prompt Validators

  • Predefined validator for validate if entered string is not empty.

    Declaration

    Swift

    @inlinable
static func notEmptyValidator(_ message: String = "The entered value cannot be empty!\n: ") -> CLI.AskOption<T>

    Parameters

    message

    The error message to display to the user if entered value is empty string.

    Return Value

    The created validator.

Predefined Prompt Validators

  • Predefined validator for validate if entered value is satisfy specified range.

    Declaration

    Swift

    @inlinable
static func rangeValidator<R>(_ range: R, _ message: String? = nil) -> CLI.AskOption<T> where T == R.Bound, R : RangeExpression

    Parameters

    range

    The range for specify value bounds.
    message

    The error message to display to the user if value is not valid.

    Return Value

    The created validator.