MBrooks

MBrooks

Programming Clojure, Third Edition: "import" for MidiNote protocol does not work (page 186)

On page 186 (last page of chapter 7) it says “The first thing we need to do is import (not use or require) our MidiNote protocol from the examples.midi namespace”.

I could not find a reason for why import, rather than use or require, should be used in this case. I am very new to Clojure but as far as I can tell, “import” is used only for importing Java classes.

When I tried using generator.clj from the REPL by running:

user=> (require '[examples.generator :refer :all])

, the “import” did not work: I got the following error:

CompilerException java.lang.ClassNotFoundException: examples.midi.MidiNote, compiling:(examples/generator.clj:11:1)

I removed the import statement and added the following require to the ns statement at the top of generator.clj:

(:require [examples.midi :refer [MidiNote key-number perform to-msec]])

After this change I was able to run generator.clj from the REPL successfully.

Marked As Solved

alexmiller

alexmiller

Author of Programming Clojure, Third Edition

Thanks for the report. It is possible for reify to either extend the class generated with the protocol or the protocol itself but regardless I’ve cleaned this part up for 4th edition.

Where Next?

Popular Pragmatic Bookshelf topics Top

abtin
page 20: … protoc command… I had to additionally run the following go get commands in order to be able to compile protobuf code using go...
New
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
Mmm
Hi, build fails on: bracket-lib = “~0.8.1” when running on Mac Mini M1 Rust version 1.5.0: Compiling winit v0.22.2 error[E0308]: mi...
New
gilesdotcodes
In case this helps anyone, I’ve had issues setting up the rails source code. Here were the solutions: In Gemfile, change gem 'rails' t...
New
swlaschin
The book has the same “Problem space/Solution space” diagram on page 18 as is on page 17. The correct Problem/Solution space diagrams ar...
New
brian-m-ops
#book-python-testing-with-pytest-second-edition Hi. Thanks for writing the book. I am just learning so this might just of been an issue ...
New
digitalbias
Title: Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana on (page 64) If you follow the defau...
New
taguniversalmachine
Hi, I am getting an error I cannot figure out on my test. I have what I think is the exact code from the book, other than I changed “us...
New
New
dachristenson
I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...
New

Other popular topics Top

PragmaticBookshelf
Learn from the award-winning programming series that inspired the Elixir language, and go on a step-by-step journey through the most impo...
New
AstonJ
Or looking forward to? :nerd_face:
498 13326 269
New
Exadra37
Oh just spent so much time on this to discover now that RancherOS is in end of life but Rancher is refusing to mark the Github repo as su...
New
rustkas
Intensively researching Erlang books and additional resources on it, I have found that the topic of using Regular Expressions is either c...
New
PragmaticBookshelf
Rails 7 completely redefines what it means to produce fantastic user experiences and provides a way to achieve all the benefits of single...
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
DevotionGeo
I have always used antique keyboards like Cherry MX 1800 or Cherry MX 8100 and almost always have modified the switches in some way, like...
New
sir.laksmana_wenk
I’m able to do the “artistic” part of game-development; character designing/modeling, music, environment modeling, etc. However, I don’t...
New
AstonJ
If you’re getting errors like this: psql: error: connection to server on socket “/tmp/.s.PGSQL.5432” failed: No such file or directory ...
New
PragmaticBookshelf
Explore the power of Ash Framework by modeling and building the domain for a real-world web application. Rebecca Le @sevenseacat and ...
New

Sub Categories: