Enum ListReq 

pub enum ListReq<T> {
    Single {
        whitelist: Option<Vec<T>>,
        default: Option<T>,
    },
    Many {
        whitelist: Option<Vec<T>>,
        required: bool,
        max_no: Option<u8>,
    },
    Predefined {
        whitelist: Option<Vec<T>>,
        default: Vec<T>,
    },
    Deny,
}

Requirements for list elements. For instance, used in AttrReq for providing crate::ParametrizedAttr fields requirements.

Variants

Single

Only a single value allowed and it must be present

Fields

whitelist: Option<Vec<T>>

Restricts set of possible values to the given whitelist

NB: If whitelist does not contain values from the default field, they are still accepted as valid, i.e. “automatically whitelisted”

default: Option<T>

Default value assigned as a signe list item if no values are provided

NB: If whitelist does not contain values from the default field, they are still accepted as valid, i.e. “automatically whitelisted”

Many

Any number of any elements may be present

Fields

whitelist: Option<Vec<T>>

Restricts set of possible values to the given whitelist

required: bool

Require that at least one value is present

max_no: Option<u8>

Restricts the maximum number of items

Predefined

Any number of any elements may not be present; if none of the elements is present the list will use default vec of the values

Fields

whitelist: Option<Vec<T>>

Restricts set of possible values to the given whitelist.

NB: If whitelist does not contain values from the default field, they are still accepted as valid, i.e. “automatically whitelisted”

default: Vec<T>

Default set of values for the list used if no values are provided

NB: If whitelist does not contain values from the default field, they are still accepted as valid, i.e. “automatically whitelisted”

Deny

Element must not be present

Implementations

impl<T> ListReq<T>

pub fn maybe_one(name: T) -> Self

Convenience constructor for list requiring presence of an optional single element.

pub fn one_of(names: Vec<T>) -> Self

Convenience constructor for list requiring presence of a single element from a list of possible values.

pub fn any_of(names: Vec<T>, required: bool) -> Self

Convenience constructor for list requiring presence of multiple elements from a list of possible values.

impl<T> ListReq<T>

where T: Clone + ToTokens,

pub fn check( &self, value: &mut Vec<T>, attr: impl ToString, arg: impl ToString, ) -> Result<(), Error>

Checks the value against the list requirements, generating Error if the requirements are not met.

Trait Implementations

impl<T: Clone> Clone for ListReq<T>

fn clone(&self) -> ListReq<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.