is there a name for this syntax? ```myCollection .map { ... } .filter { ... } .forEach {...

# announcements

[Rainer Schlonvoigt]

is there a name for this syntax?

myCollection
    .map { ... }
    .filter { ... }
    .forEach { ... }

I know in Java i would call it “stream syntax” but that’s because there you actually need to create streams before being able to make these calls

[arekolek]

chained calls?

eg. https://kotlinlang.org/docs/reference/coding-conventions.html#chained-call-wrapping

[Matteo Mirk]

it’s not specific to Streams, it’s called “fluent API” https://en.wikipedia.org/wiki/Fluent_interface

[Rainer Schlonvoigt]

that article refers to https://en.wikipedia.org/wiki/Method_chaining

[stephanmg]

Maybe unrelated: What’s the design patterns one would use for achieving this? Decorators?

[Matteo Mirk]

no, in Java and similar would be the Builder pattern, and DSL builders in Kotlin

[stephanmg]

Fluent makes sense, I know this terminology from C# LINQ and folks use this I think

[stephanmg]

ah yes, Builder would make more sense actually 🥵

[Matteo Mirk]

@Rainer Schlonvoigt yeah, but chaining is just a “tool”, “fluent interface” is the concept or pattern, it encompasses it

[stephanmg]

here they speak about fluent interface as a pattern https://medium.com/better-programming/what-is-the-fluent-interface-design-pattern-2797645b2a2e

[stephanmg]

if somebody cares

[Matteo Mirk]

Cool, thanks. Speaking of the builder pattern, there is a nifty variation that I like but it’s little known: https://www.endoflineblog.com/type-safe-builder-pattern-in-java-and-the-jilt-library
a more advanced use of fluent interfaces

[stephanmg]

Interesting.