clojure.md

clojure

Jira https://clojure.atlassian.net/

Spelunking through source code

compiler

https://clojure.org/reference/compilation

• Opcodes.java

• Compiler.java

  • public static Object compile a good starting point, see how it concludes with getting byte array from class writer/visitor and writing it to a class file
  • public static Object eval(Object form)
    • see inner interface Expr#eval, class ObjExpr etc.

• see (defn load in core.java

    (clojure.lang.RT/load (.substring path 1))
  

• Compile.java just a main method that invokes core compile

• core defn compile

• Symbol.java, intern()

• Var.java, setDynamic()

• Intrinsics.java

reader

https://clojure.org/reference/reader see also https://clojure.org/reference/evaluation

• LispReader.java

• see defn read in core.clj

    ([opts stream]
     (. clojure.lang.LispReader (read stream opts)))
  

  • *read-eval*

  Note that read can execute code (controlled by read-eval)...

  • see also read-string core function

• EdnReader.java

• See also tools.reader: a reader implemented in Clojure, replaces LispReader

Alex

You can invoke the Clojure.read() function to read a literal map or Clojure.var() to look up Clojure vars and invoke them

• This ^ refers to clojure.java.api.Clojure
  • public static Object read(String s)
  • public static IFn var(...) overloaded

compojure

Starting REST API

• ring - https://github.com/ring-clojure/ring

  • https://www.baeldung.com/clojure-ring
  • ring-mock https://github.com/ring-clojure/ring-mock

• compojure - https://github.com/weavejester/compojure

    $ lein new compojure hello-world
    $ lein ring server
  

• https://github.com/ring-clojure/ring-defaults

• see also

  • https://github.com/metosin/compojure-api
  • https://github.com/metosin/reitit

Sean Corfield talk 12/15/20

• CLI tools (1.10.1.763) plus dot-clojure repo/aliases
• VS Code + Clover + Socket REPL
• possible with lein, nREPL, emacs/vi/cursive
• tools.deps.alpha's add-lib3 branch to add dependencies to running app (can use Pomegrante with lein for same thing)
• Reveal (optional, supliment editor) see also: REBL (Cognitect)
• clj-kondo (borkdude)
• strict paredit
• parinfer
• tap
• selmer templating (similar to django, see also hiccup)
• spec
• Cryogen clojure markdown

require/load/use

require -

• must require ns before using

load -

use -

Require isn't thread-safe https://ask.clojure.org/index.php/9893/require-is-not-thread-safe

• core defn- serialized-require, defn requiring-resolve
• clojure.lang.RT/REQUIRE_LOCK

clojure|clj

Install from the official tap (not the homebrew built-in formula)

brew install clojure/tools/clojure

https://clojure.org/releases/tools

installed clj, rlwrap https://clojure.org/guides/getting_started

Use the linux-install script to download and run the install, which will create the executables /usr/local/bin/clj, /usr/local/bin/clojure, and the directory /usr/local/lib/clojure:

According to Alex

tools.build is coming...

The brew-install repo contains the installed scripts including (confusingly) the linux-install.sh script

commands

man clojure
clojure -X:deps tree

repl

lein leiningen repl nrepl tools.nrepl cider repl-y reply

• tools.nrepl successor is nrepl (0.3.1 should be drop-in replacement for 0.2.13)
  • https://github.com/nrepl/nrepl
• reply aka REPL-y - a replacement for stock Clojure repl, unrelated to nrepl (but with integration)
  • https://github.com/trptcolin/reply

Upgrade a bunch of other packages including cider. As a reminder to self, then had to go update version of cider-nrepl to match, in both ~/.lein/profiles.clj and ~/.gradle/gradle.properties.

Investigating Gradle clojure cider-nrepl support

• tools.nrepl - https://github.com/clojure/tools.nrepl
  • server.clj defines defn start-server, defn default-handler
• leiningen - https://github.com/technomancy/leiningen
  • repl.clj
    • defn- server-forms builds handler, overrideable by plugins (e.g. for additional middleware)
    • defn- handler-for uses nrepl-middleware from project.clj
• cider-nrepl - https://github.com/clojure-emacs/cider-nrepl
  • additional middleware for tools.nrepl
  • plugin.clj (lein plugin) adds its own middleware to :repl-options :nrepl-middleware of project.clj
  • See ~/.lein/profiles.clj - this sets the lein repl plugin
• gradle-clojure - https://github.com/clojurephant/clojurephant
  • gradle plugin providing simple clojure support
  • clojure_nrepl.clj - simply calls nrepl/start-server only specifying port - no hook to override middleware

clojure main

https://clojure.org/reference/repl_and_main

• main.java public static void main (refered to by jar manifest.mf, see build.xml)
• main.clj defn main no args case
• main.clj defn repl actually implements a repl

"read-eval" refers to reading forms (the Clojure "reader") followed by eval (can include compilation)