dtonhofer

dtonhofer

Functional Programming in Java, Second Edition: Chapter 12 "Functional Programming Idioms", some notes

On page 179:

First, imperative style was the way of life in Java and most programmers are very familiar with that style, since that was the only option for a long time.

In other words: Java is a member of the family of ALGOL-style languages derived from ALGOL 60.

A subchapter that is missing may be;

Use Records

Functional languages allow creation of data structures “on the fly” (e.g. the LISP cons or the Clojure “map” construct), the near-equivalent seems to be the record. It is very useful in stream pipelines to create new forms of data to be passed rightwards. It’s definitely more informative than using general maps for this task.

However, records should probably not be used outside of a local context or even in an API, use proper classes for that.

In

Use Type Inference for Parameters

one might mention that using var for field declarations is a good thing and not shameful, unless it is better to write the whole type for clarity for the other members of the team. (but the IDE will inline a note on the type anyway)

A special note on

Datastructures

which for functional programming are either primitive and immutable or complex and “pretend immutable” by not allowing any modifications, only allowing 1) copying 2) creating a modified copy (which is done efficiently “under the hood”) Only dropping references to whole or parts of these structures will allow reduction in size via eventual garbage collection.

For example, in Clojure: Clojure - Data Structures

However, Java collections for example are not like that at all, at best we can make them immutable by wrapping with an “unmodifiable” decorator. What is to be done? Are there libraries that have tree structures (say) that efficiently implement “immutability” semantics.

Where Next?

Popular Pragmatic Bookshelf topics Top

jimmykiang
This test is broken right out of the box… — FAIL: TestAgent (7.82s) agent_test.go:77: Error Trace: agent_test.go:77 agent_test.go:...
New
telemachus
Python Testing With Pytest - Chapter 2, warnings for “unregistered custom marks” While running the smoke tests in Chapter 2, I get these...
New
AleksandrKudashkin
On the page xv there is an instruction to run bin/setup from the main folder. I downloaded the source code today (12/03/21) and can’t see...
New
joepstender
The generated iex result below should list products instead of product for the metadata. (page 67) iex> product = %Product{} %Pento....
New
Chrichton
Dear Sophie. I tried to do the “Authorization” exercise and have two questions: When trying to plug in an email-service, I found the ...
New
jgchristopher
“The ProductLive.Index template calls a helper function, live_component/3, that in turn calls on the modal component. ” Excerpt From: Br...
New
jskubick
I’m under the impression that when the reader gets to page 136 (“View Data with the Database Inspector”), the code SHOULD be able to buil...
New
nicoatridge
Hi, I have just acquired Michael Fazio’s “Kotlin and Android Development” to learn about game programming for Android. I have a game in p...
New
jonmac
The allprojects block listed on page 245 produces the following error when syncing gradle: “org.gradle.api.GradleScriptException: A prob...
New
davetron5000
Hello faithful readers! If you have tried to follow along in the book, you are asked to start up the dev environment via dx/build and ar...
New

Other popular topics Top

ohm
Which, if any, games do you play? On what platform? I just bought (and completed) Minecraft Dungeons for my Nintendo Switch. Other than ...
New
brentjanderson
Bought the Moonlander mechanical keyboard. Cherry Brown MX switches. Arms and wrists have been hurting enough that it’s time I did someth...
New
New
AstonJ
I have seen the keycaps I want - they are due for a group-buy this week but won’t be delivered until October next year!!! :rofl: The Ser...
New
PragmaticBookshelf
Author Spotlight Mike Riley @mriley This month, we turn the spotlight on Mike Riley, author of Portable Python Projects. Mike’s book ...
New
PragmaticBookshelf
Programming Ruby is the most complete book on Ruby, covering both the language itself and the standard library as well as commonly used t...
New
First poster: bot
zig/http.zig at 7cf2cbb33ef34c1d211135f56d30fe23b6cacd42 · ziglang/zig. General-purpose programming language and toolchain for maintaini...
New
New
NewsBot
Node.js v22.14.0 has been released. Link: Release 2025-02-11, Version 22.14.0 'Jod' (LTS), @aduh95 · nodejs/node · GitHub
New
RobertRichards
Hair Salon Games for Girls Fun Girls Hair Saloon game is mainly developed for kids. This game allows users to select virtual avatars to ...
New

Latest in Functional Programming in Java, Second Edition

Functional Programming in Java, Second Edition Portal

Sub Categories: