This course is inspired by and borrows from the excellent Clojure Mooc by the by the CS department of University of Helsinki.
Focuses on:
- use the repl for fast learning feedback.
- writing human friendly code from the start
- avoiding clojure's pain points
- uses familiar problem domains
Setup
-
Join Clojurians on Slack. (most important step - google then ask on beginners if you get stuck at any point)
-
Get Git
-
get the repo:
git clone https://github.com/peter-wilkins/clojure-course.git -
Get Leiningen
Editors - the instructions in the chapters assume cursive but if you prefer another and know how to repl already use whatever you want
- Get Intellij Community Edition
- Get Cursive
Shortcuts - Learn or change 2 shortcuts in Intellij for REPL happiness
- Load File in REPL
- Send Form Before Caret to REPL
Starting a REPL
Open clojure-course in intellij as a project
Right click on project.clj and select + Add as leiningen project
wait for intellij to finish syncronising
Right click on project.clj and select Run REPL for ...
Open src/thread_the_needle.clj
Use your shortcut to Load File in REPL
Common Repl Error messages and what they mean:
Error: :namespace-not-found
-> you need to Load File in REPL
CompilerException java.lang.ClassCastException: class XXX cannot be cast to class clojure.lang.IFn
-> "This XXX cannot be turned into a Function"
-> the first form inside a brackets always needs to be a function i.e. (1) errors while (inc 0) is fine
CompilerException clojure.lang.ArityException: Wrong number of args (0) passed to: core/inc--inliner--5258
-> (inc) errors as inc expects exactly one arg
IllegalArgumentException Don't know how to create ISeq from: XXX
-> "this XXX cannot be turned into a sequence"
-> collection functions expect the collection as the last arg e.g. (map inc [1 2 3]) not (map [1 2 3] inc)
CompilerException java.lang.RuntimeException: EOF while reading -> you are missing a closing bracket somewhere
Recommended Order for Exercises:
- src/thread-the-needle.clj
- src/p-p-p-pokerface.clj
Then do rest of the Mooc
Extras
- src/specter-gadget.clj
- src/composing-transducers.clj