Crate fluent_builder

A simple builder for constructing or mutating values.

This crate provides a simple FluentBuilder structure. It offers some standard behaviour for constructing values from a given source, or by mutating a default that's supplied later. This crate is intended to be used within other builders rather than consumed by your users directly.

Usage

Create a FluentBuilder and construct a default value:

use fluent_builder::FluentBuilder;

let builder = FluentBuilder::<String>::default();

let value = builder.into_value(|| "A default value".to_owned());

assert_eq!("A default value", value);

Values can be supplied to the builder directly. In this case that value will be used instead of constructing the default:

use fluent_builder::FluentBuilder;

let builder = FluentBuilder::<String>::default().value("A value".to_owned());

let value = builder.into_value(|| "A default value".to_owned());

assert_eq!("A value", value);

Mutating methods can be stacked and will either be applied to a concrete value, or the constructed default:

use fluent_builder::FluentBuilder;

let builder = FluentBuilder::<String>::default()
    .fluent_mut(|s| s.push_str(" fluent1"))
    .fluent_mut(|s| s.push_str(" fluent2"));

let value = builder.into_value(|| "A default value".to_owned());

assert_eq!("A default value fluent1 fluent2", value);

Fluent builders can also be used to thread required state through construction:

use fluent_builder::StatefulFluentBuilder;

#[derive(Debug, PartialEq, Eq)]
struct Builder {
    required: String,
    optional: Option<String>,
}

let builder = StatefulFluentBuilder::<Builder, String>::from_seed("A required value".to_owned())
    .fluent_mut("A required value".to_owned(), |b, s| {
        b.required = s;
        if let Some(ref mut optional) = b.optional.as_mut() {
            optional.push_str(" fluent1");
        }
    });

let value = builder.into_value(|s| Builder {
    required: s,
    optional: Some("A default value".to_owned())
});

assert_eq!("A required value", value.required);
assert_eq!("A default value fluent1", value.optional.unwrap());

Structs

FluentBuilder	A structure that can contain a value, or stack mutating methods over one supplied later.
StatefulFluentBuilder	A stateful structure that can contain a value, or stack mutating methods over one supplied later.