Struct derive_builder_core::Block

pub struct Block(_);

A permissive wrapper for expressions/blocks, implementing quote::ToTokens.

• full access to variables environment.
• full access to control-flow of the environment via return, ? etc.

Examples

Will expand to something like the following (depending on settings):

{ x + 1 }

Trait Implementations

impl Clone for Block

fn clone(&self) -> Block

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Default for Block

fn default() -> Self

Returns the "default value" for a type.

impl Debug for Block

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

Formats the value using the given formatter.

impl FromStr for Block

type Err = String

The associated error which can be returned from parsing.

fn from_str(expr: &str) -> Result<Self, Self::Err>

Parses a string s to return a Block.

Errors

When expr cannot be parsed as Vec<syn::TokenTree>. E.g. unbalanced opening/closing delimiters like {, ( and [ will be rejected as parsing error.

impl ToTokens for Block

fn to_tokens(&self, tokens: &mut TokenStream)

Write self to the given TokenStream.

fn into_token_stream(self) -> TokenStream

Convert self directly into a TokenStream object.