Next Level DSLs Configure your app the Kotlin way! Aaron Sarazan - PowerPoint PPT Presentation

Next Level DSLs Configure your app the Kotlin way! Aaron Sarazan CTO - Stencil Ltd. https://gitlab.com/asarazan/kotlinconf18 aaron@stencil.ltd

Isolated Feature Development

A Plugin It’s like an app, just smaller

Android Manifest

Plugin DSL

Plugin DSL

Plugin DSL

Plugin DSL

Plugin DSL

Back to Basics

Help! What’s a DSL?

When you really wish your language could do the thing.

Help! What’s a DSL? Java

Help! What’s a DSL? LISP

Help! What’s a DSL? Ruby

Podfiles

Help! What’s a DSL? Domain Specific Language

white space

Remove Boilerplate

Help! What’s a DSL? Domain Specific Language

Help! What’s a DSL? Domain Specific Language

Help! What’s a DSL? Domain Specific Language

Help! What’s a DSL? Domain Specific Language

You don’t DO the thing. You STATE the thing.

GRADLE!

Here’s How It Works

Here’s How It Works

Here’s How It Works

Experience Get!

Why Kotlin?

Groovy-Style Type-Safe Builders

It was literally built for it. Kotlin is made for DSLs

When Should I Make a DSL?

Anko

Anko

Anko

● XML This is Really Unpleasant ● Configuration ● Declaration ...and there has to be a better way. ● Boilerplate ● Builders

Builders ALWAYS a candidate for DSLs

Readability

Work Backwards Start from the result that you want to enable ...then write the code that enables it!

Start With Builders Immutability with a side of Java-friendliness!

@DslMarker Prevent Scoping Mishaps!

Don’t pollute the global namespace ● Good Hygiene Unary “+” only if well-scoped ● Keep Lambda files next to your builder classes ● Plugin.kt ○ PluginLambdas.kt ○ Don’t extend system types ● String, Int, etc. ○

Don’t pollute the global namespace ● Unary “+” only if well-scoped ● Good Hygiene Keep Lambda files next to your builder classes ● Plugin.kt ○ PluginLambdas.kt ○ Don’t extend system types ● String, Int, etc. ○ Have fun! ●

So Who’s Ready?

Follow Along At Home ● https://gitlab.com/asarazan/kotlinconf18

Thank You aaron@stencil.ltd https://gitlab.com/asarazan/kotlinconf18

DSLs 1 EVERYWHERE

Kotlin’s Strongest Metaphors Applied to Java’s biggest bummers

How Did We Get Here?

Value Types & Structs!!!

Next Level DSLs Configure your app the Kotlin way! Aaron Sarazan CTO - Stencil Ltd. https://gitlab.com/asarazan/kotlinconf18 aaron@stencil.ltd

How About That Keynote? I can’t wait to get home and try out {AWESOME NEW FEATURE}

Next Level DSLs Configure your app the Kotlin way! Aaron Sarazan CTO - Stencil Ltd. https://gitlab.com/asarazan/kotlinconf18 aaron@stencil.ltd

Follow Along At Home ● https://gitlab.com/asarazan/kotlinconf18

Why Kotlin?