Clojure friendly mode, inspired by https://github.com/slipset/friendly

README.md

Friendly

A beginner-friendly REPL that combines

• rebel-readline
• Expound
• Speculative

Usage

JVM 8:

clojure -Sdeps '{:deps {friendly {:git/url "https://gist.github.com/bhb/2686b023d074ac052dbc21f12f324f18" :sha "d532662414376900c13bed9c920181651e1efeff"}}}' -X friendly/run

JVM 9 or newer:

clojure -Sdeps '{:deps {friendly {:git/url "https://gist.github.com/bhb/2686b023d074ac052dbc21f12f324f18" :sha "d532662414376900c13bed9c920181651e1efeff"}}}' -X friendly/run

Credits

Inspired by https://github.com/slipset/friendly

I learned the technique of loading code via a gist from https://gist.github.com/athos/b68b15b08efedffaf14d8c020b125202

deps.edn

{:paths ["."]
 :deps {com.bhauman/rebel-readline {:mvn/version "0.1.4"}
        expound/expound {:mvn/version "0.9.0"}
        org.clojure/core.specs.alpha {:mvn/version "0.2.62"}
        speculative/speculative {:git/url "https://github.com/borkdude/speculative.git"
                                 :sha "4e773794a4065a84bdadd997516e52c76ab51b1f"}}}

friendly.clj

(ns friendly
  (:require [rebel-readline.clojure.main]
            [expound.alpha :as expound]
            [clojure.spec.alpha :as s]
            [clojure.stacktrace]
            [clojure.main]
            ;; for specs
            [speculative.instrument :as speculative]))

(expound/defmsg :speculative.specs/ifn "should be a function (or a value that can be *treated* like a function e.g. a set or keyword)")

(def printer (expound/custom-printer {:print-specs? false
                                      :show-valid-values? true
                                      :theme :figwheel-theme}))

(defn repl-caught [e]
  (let [ex (clojure.main/repl-exception e)
        tr (.getStackTrace ex)
        el (when-not (zero? (count tr)) (aget tr 0))
        ex-m (Throwable->map ex)]
    (binding [*out* *err*]
      (cond
        ;; If the output is a clojure spec issue...
        (::s/problems (:data ex-m))
        ;; print expound output
        (do
          (println (str (re-find  #"Call to .* did not conform to spec\:" (.getMessage ex))
                        "\n"
                        (with-out-str (printer (:data ex-m))))))

        (instance? clojure.lang.LispReader$ReaderException e)
        (println (:cause (Throwable->map e)))

        :else
        ;; otherwise print exception
        (println (str (if (instance? clojure.lang.Compiler$CompilerException ex)
                        (str
                         (-> ex class .getSimpleName)
                         " " (.getMessage ex) " ")
                        (str " " (if el
                                   (clojure.stacktrace/print-stack-trace ex)
                                   "[trace missing]")))))))))


(speculative/instrument)
(set! s/*explain-out* printer)

(defn run [_opts]
  (rebel-readline.clojure.main/repl :caught repl-caught))

Thanks @andnils for the fix!!!