Struct Block

pub struct Block<T>(/* private fields */);

A transparent wrapper type which hints the Serializer to serialize T as an HCL block.

When passed to a serializer other than the one from this crate, a Block<T> serializes exactly like T, if T implements serde::Serialize.

A Block<T> can only be used in the value position of a map-like structure. For example:

• It can be used to wrap the value type of a map, e.g. Map<K, Block<T>>
• As the value of a struct field, e.g. struct S { field: Block<T> }
• Or as the value of an enum variant, e.g. enum E { Variant(Block<T>) }

The serialized block’s identifier will be the respective map key, struct field name or variant name.

The wrapped T must be shaped as follows to be serialized as an HCL block:

• A map-like value (e.g. a map or struct).
• A sequence-like value (e.g. a vector, slice or tuple) with map-like elements as described above. In this case, multiple blocks with the same identifier are produced.

Wrapping a type T that does not fulfil one of the criteria above in a Block<T> will result in serialization errors.

For more convenient usage, see the block function.

Example

use hcl::ser::Block;
use serde::Serialize;

#[derive(Serialize)]
struct Config {
    user: Block<Vec<User>>,
}

#[derive(Serialize)]
struct User {
    name: String,
    email: String,
}

let users = vec![
    User {
        name: "john".into(),
        email: "johndoe@example.com".into(),
    },
    User {
        name: "jane".into(),
        email: "janedoe@example.com".into(),
    },
];

let config = Config {
    user: Block::new(users),
};

let expected = r#"
user {
  name = "john"
  email = "johndoe@example.com"
}

user {
  name = "jane"
  email = "janedoe@example.com"
}
"#.trim_start();

assert_eq!(hcl::to_string(&config)?, expected);

Implementations

impl<T> Block<T>

pub fn new(value: T) -> Block<T>

Create a new Block<T> from a T.

pub fn into_inner(self) -> T

Consume the Block and return the wrapped T.

Trait Implementations

impl<T> Clone for Block<T>

where T: Clone,

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Block<T>

where T: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Deref for Block<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<T> DerefMut for Block<T>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<'de, T> Deserialize<'de> for Block<T>

where T: Deserialize<'de>,

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T> Serialize for Block<T>

where T: Serialize,

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.