Builder syntax

[RustyYato]

This is a well trodden problem: It even has an implementation as a crate https://crates.io/crates/cascade

Previous motivations:

Why does `Vec::push` not return a mutable reference to itself?

Can we have this API? impl<T> Vec<T> { pub fn push(&mut self, value: T) -> &mut Self; } So we can allow the following pattern: pub fn foo() -> Vec<char> { Vec::new().push('f').push('o').push('o') }

Previous discussions:

Method-cascading and pipe-forward operators proposal

In this topic I want to draw attention, show purpose and share initial idea about syntax for them. Before reading, note: I’m just an enthusiast - don’t take that too seriously and don’t be too critical if something wrong; prepare to bad English. Jump to second version - text below is not actual It consists of two parts because in my proposal both are related and second can be combined with first to cover additional use case. Also, both have different syntax from one that may be found in ot…

Method chaining special form

A few methods have slipped in that, as far as I can tell, are just to make method chaining more convenient. In particular, Vec.append_one is just a push that returns self afterwards. Rather than bloat up the API with lots of similar-but-subtly-different methods, I’d prefer if this pattern were generalized to something reusable. Ruby has tap for exactly this, and tap could be implemented pretty easily in Rust, though it’s exceptionally verbose: //Stolen from kimundi trait Tap {     fn tap(mut…