---
title: "Functional Swift Conference 2017 — Brooklyn"
description: "Kickstarter hosted the fourth Functional Swift Conference on April 15th, marking the third time the event had been held at its office. The all-day gathering brought together 10 speakers, including four Kickstarter engineers, and 90 attendees to discuss what functional programming can contribute to better Swift code. Sessions covered recursive enums and KD-trees, testing side-effects, domain-specific languages with GraphQL, algebraic laws, monoids, predicates, sorting functions, applicative functors, parsing, and type inference. Examples included using value types and recursive data structures to describe complicated objects and live-coding an applicative parsing API that generates its own documentation. The closing type-system talk examined why inference is hard and described the Swift compiler team’s use of graph theory to address inference problems practically."
---

# Functional Swift Conference 2017 — Brooklyn

[Kickstarter](https://yomu.fyi/company/kickstarter) · Brandon Williams · Apr 28, 2017

**Type:** Announcement

## Summary

Kickstarter hosted the fourth Functional Swift Conference on April 15th, marking the third time the event had been held at its office. The all-day gathering brought together 10 speakers, including four Kickstarter engineers, and 90 attendees to discuss what functional programming can contribute to better Swift code. Sessions covered recursive enums and KD-trees, testing side-effects, domain-specific languages with GraphQL, algebraic laws, monoids, predicates, sorting functions, applicative functors, parsing, and type inference. Examples included using value types and recursive data structures to describe complicated objects and live-coding an applicative parsing API that generates its own documentation. The closing type-system talk examined why inference is hard and described the Swift compiler team’s use of graph theory to address inference problems practically.

## Context

The conference centered on what can be learned from functional programming to write better Swift code. Its program brought together discussions of functional techniques, testing, language design, parsing, and type inference.

## Approach / What changed

Kickstarter presented an all-day program with 10 speakers, including four Kickstarter engineers, across talks, live coding, and practical examples. Topics included recursive data structures for KD-trees, describing side-effects for testing, GraphQL-based domain-specific languages, applicatives, and graph theory applied to type inference.

## Takeaways

- Konrad Feiler applied value types and recursive data structures to KD-trees, using them to describe complicated objects and demonstrate their performance properties.
- Matt Diephouse argued that describing side-effects instead of performing them can provide greater testability and understandability than relying on test doubles.
- Chris Eidhof live-coded an applicative parsing API that generates its own documentation, while Robert Widmann discussed graph theory as a practical tool for type-inference problems.

**Tags:** [GraphQL](https://yomu.fyi/topic/graphql), [iOS](https://yomu.fyi/topic/ios), [Performance](https://yomu.fyi/topic/performance), [Testing](https://yomu.fyi/topic/testing)

- Source: [Kickstarter](https://medium.com/kickstarter-engineering/functional-swift-conference-2017-brooklyn-69341a22645c)
- Source URL: https://medium.com/kickstarter-engineering/functional-swift-conference-2017-brooklyn-69341a22645c
- Ingested by Yomu: 2026-08-30T12:07:25.754Z

[Read original post](https://medium.com/kickstarter-engineering/functional-swift-conference-2017-brooklyn-69341a22645c)