Add print and caught hooks

Author: JarrodCTaylor

README.md

@@ -61,6 +61,8 @@ Use aliases `:clj-line/client` or `:clj-line/server` for more precise targeting.
 | `:auto-require` | client | vector of libspecs | Required into each namespace. |
 | `:middleware` | server | vector of qualified symbols | nREPL middleware.                      |
 | `:eval-hook` | server | qualified symbol | Wraps eval: `(f eval)` returns the eval fn.     |
+| `:print-hook` | server | qualified symbol | Wraps result printing: `(f print)` returns a fn with signature `[value writer options]`. |
+| `:caught-hook` | server | qualified symbol | Wraps error reporting: `(f caught)` returns a fn with signature `[throwable]`. |
 | `:port` | server | int | nREPL port (OS-assigned). |
 | `:print-length` | server | int | `*print-length*` (`nil`). |
 | `:print-level` | server | int | `*print-level*` (`nil`). |
@@ -81,22 +83,18 @@ Use aliases `:clj-line/client` or `:clj-line/server` for more precise targeting.
 - [x] Emacs/Vim editing key commands
 - [x] Custom keybindings
 - [x] Auto require
-- [x] Print var defaults (`*print-level*`, `*print-length*`, `*print-namespace-maps*`, etc)
-- [ ] Customized exception printer function
-- [ ] Read, Eval, Print, Caught hooks
+- [x] Dynamic var config (`*print-level*`, `*print-length*`, `*warn-on-reflection*`, etc)
+- [x] Print and Caught hooks (Read is the client's parser, reachable via `:keybindings`)
 - [ ] Bracket pairs & structural-editing
 - [ ] Docs
+- [ ] Inline tab completion of symbols (function or class)
 - [ ] Secondary prompt (format and content of continuation line, line numbers, colors)
-- [ ] Pretty-print toggle
 - [ ] Tap: (on/off, tap out text, filter pred)
-- [ ] Auto indent, column alignment (let columns and other things people align)
-- [ ] Inline tab completion of symbols (function or class)
 - [ ] REPL commands like :prompt (custom?)
 - [ ] Status line (on/off)
-- [ ] Input value coloring by type
-- [ ] Output value coloring by type
-- [ ] Indentation rules (basic alignment after each new bracket context)
-- [ ] Inline eval of form under cursor output to tap above
+- [ ] -Input value coloring by type-
+- [ ] -Output value coloring by type-
+- [x] Inline eval of form under cursor output to tap above (User space example)
 
 ## Tests
 

server/src/clj_line/server.clj

@@ -3,7 +3,7 @@
     [clojure.java.io :as io]
     [nrepl.config :as nrepl-config]
     [nrepl.server :as server]
-    [clj-line.server.eval-hook :as hook]))
+    [clj-line.server.hooks :as hooks]))
 
 (set! *warn-on-reflection* true)
 
@@ -25,13 +25,12 @@
              {}
              dynamic-vars))
 
-(defn start [{:keys [eval-hook middleware port] :as config}]
+(defn start [{:keys [middleware port] :as config}]
   (when-let [vars (not-empty (configured-dynamic-vars config))]
     (alter-var-root #'nrepl-config/config assoc :dynamic-vars vars))
-  (when eval-hook
-    (hook/install (requiring-resolve eval-hook)))
+  (hooks/install config)
   (let [extra (mapv requiring-resolve middleware)
-        handler (apply server/default-handler #'hook/middleware extra)
+        handler (apply server/default-handler #'hooks/middleware extra)
         srv (server/start-server :port (or port 0) :handler handler)]
     (spit ".nrepl-port" (str (:port srv)))
     srv))

server/src/clj_line/server/eval_hook.clj

@@ -0,0 +1,38 @@
+(ns clj-line.server.hooks
+  (:require
+    [clojure.main :as main]
+    [nrepl.middleware :refer [set-descriptor!]]
+    [nrepl.middleware.caught :as caught]
+    [nrepl.middleware.print :as print]))
+
+(set! *warn-on-reflection* true)
+
+(def default-eval eval)
+(def default-print print/*print-fn*)
+(def default-caught main/repl-caught)
+
+(def evaluator (atom nil))
+(def printer (atom nil))
+(def catcher (atom nil))
+
+(defn hooked-eval [form] (@evaluator form))
+(defn hooked-print [value writer options] (@printer value writer options))
+(defn hooked-caught [throwable] (@catcher throwable))
+
+(defn install [{:keys [eval-hook print-hook caught-hook]}]
+  (when eval-hook (reset! evaluator ((requiring-resolve eval-hook) default-eval)))
+  (when print-hook (reset! printer ((requiring-resolve print-hook) default-print)))
+  (when caught-hook (reset! catcher ((requiring-resolve caught-hook) default-caught))))
+
+(defn middleware [handler]
+  (fn [{:keys [op] :as msg}]
+    (handler (if (= op "eval")
+               (cond-> msg
+                 @evaluator (assoc :eval (str `hooked-eval))
+                 @printer (assoc ::print/print (str `hooked-print))
+                 @catcher (assoc ::caught/caught (str `hooked-caught)))
+               msg))))
+
+;; Order the middleware before the nrepl eval handler
+(set-descriptor! #'middleware
+  {:requires #{} :expects #{"eval"} :handles {}})