Simplify printing configuration

* New options:
** cider-print-fn
** cider-print-options
** cider-print-quota

* Options made obsolete:
** cider-pprint-fn
** cider-pprint-options
** cider-stacktrace-print-options
** cider-debug-print-options
** cider-repl-pretty-print-width

* Add functions to construct requests for either pretty-printing or printing
  with clojure.core/pr, and use these functions where relevant.

* Use map.el functions for merging partial requests.

* Prefer any width value in cider-print-options to the advised value provided by
  fill-column, to allow overriding this option without needing a separate
  variable.

Author: cichli

cider-client.el

@@ -25,16 +25,18 @@
 
 ;;; Code:
 
+(require 'map)
+(require 'seq)
+(require 'subr-x)
+
+(require 'clojure-mode)
 (require 'spinner)
-(require 'nrepl-client)
+
+(require 'cider-compat)
 (require 'cider-connection)
 (require 'cider-common)
 (require 'cider-util)
-(require 'clojure-mode)
-
-(require 'subr-x)
-(require 'cider-compat)
-(require 'seq)
+(require 'nrepl-client)
 
 
 ;;; Eval spinner
@@ -195,71 +197,71 @@ buffer, defaults to (cider-current-repl)."
 If NS is non-nil, include it in the eval request."
   (nrepl-sync-request:eval input (or connection (cider-current-repl)) ns))
 
-(defcustom cider-pprint-fn 'pprint
-  "Sets the function to use when pretty-printing evaluation results.
+(defcustom cider-print-fn 'pprint
+  "Sets the function to use for printing.
 
-The value must be one of the following symbols:
+nil – to defer to nREPL to choose the printing function.  This will use
+the bound value of \\=`nrepl.middleware.print/*print-fn*\\=`, which
+defaults to the equivalent of \\=`clojure.core/pr\\=`.
 
-`pprint' - to use \\=`clojure.pprint/pprint\\=`
+`pr' – to use the equivalent of \\=`clojure.core/pr\\=`.
 
-`fipp' - to use the Fast Idiomatic Pretty Printer, approximately 5-10x
-faster than \\=`clojure.core/pprint\\=` (this is the default)
+`pprint' – to use \\=`clojure.pprint/pprint\\=` (this is the default).
 
-`puget' - to use Puget, which provides canonical serialization of data on
-top of fipp, but at a slight performance cost
+`fipp' – to use the Fast Idiomatic Pretty Printer, approximately 5-10x
+faster than \\=`clojure.core/pprint\\=`.
 
-`zprint' - to use zprint, a fast and flexible alternative to the libraries
+`puget' – to use Puget, which provides canonical serialization of data on
+top of fipp, but at a slight performance cost.
+
+`zprint' – to use zprint, a fast and flexible alternative to the libraries
 mentioned above.
 
-Alternatively, can be the namespace-qualified name of a Clojure function of
-two arguments - an object to print and an options map.  The options map will
-have string keys.  If the function
-cannot be resolved, an exception will be thrown.
-
-The function should ideally have a two-arity variant that accepts the
-object to print and a map of configuration options for the printer.  See
-`cider-pprint-options' for details.
-
-The function is also assumed to respect the contract of
-\\=`clojure.pprint/pprint\\=` with respect to the bound values of
-\\=`*print-length*\\=`, \\=`*print-level*\\=`, \\=`*print-meta*\\=`, and
-\\=`clojure.pprint/*print-right-margin*\\=`.  Those would normally serve as
-fallback values when a map of print options is not supplied explicitly."
-  :type '(choice (const pprint)
+Alternatively can be the namespace-qualified name of a Clojure var whose
+function takes three arguments: the object to print, the
+\\=`java.io.PrintWriter\\=` to print on, and a (possibly nil) map of
+options.  If the function cannot be resolved, will behave as if set to
+nil."
+  :type '(choice (const nil)
+                 (const pr)
+                 (const pprint)
                  (const fipp)
                  (const puget)
                  (const zprint)
                  string)
   :group 'cider
-  :package-version '(cider . "0.11.0"))
+  :package-version '(cider . "0.21.0"))
 
-(defcustom cider-pprint-options nil
-  "A list of options for the pretty-printer that will be converted to a map.
-Note that map can only have string keys, so the printer functions should be
-able to handle those.  Here's an example for `pprint':
+(defcustom cider-print-options nil
+  "A map of options that will be passed to `cider-print-fn'.
+Here's an example for `pprint':
 
-  '(dict \"length\" 50 \"right-margin\" 70)"
+  '((\"length\" 50) (\"right-margin\" 70))"
   :type 'list
   :group 'cider
-  :package-version '(cider . "0.20.0"))
+  :package-version '(cider . "0.21.0"))
+
+(make-obsolete-variable 'cider-pprint-fn 'cider-print-fn "0.21")
+(make-obsolete-variable 'cider-pprint-options 'cider-print-options "0.21")
 
-(defun cider--pprint-fn ()
-  "Return the value to send in the pprint-fn slot of messages."
-  (pcase cider-pprint-fn
 (defcustom cider-print-quota (* 1024 1024)
   "A hard limit on the number of bytes to return from any printing operation.
 Set to nil for no limit."
   :type 'integer
   :group 'cider
   :package-version '(cider . "0.21.0"))
 
+(defun cider--print-fn ()
+  "Return the value to send in the nrepl.middleware.print/print slot."
+  (pcase cider-print-fn
+    (`pr     "cider.nrepl.pprint/pr")
     (`pprint "cider.nrepl.pprint/pprint")
-    (`fipp "cider.nrepl.pprint/fipp-pprint")
-    (`puget "cider.nrepl.pprint/puget-pprint")
+    (`fipp   "cider.nrepl.pprint/fipp-pprint")
+    (`puget  "cider.nrepl.pprint/puget-pprint")
     (`zprint "zprint.core/zprint-str")
-    (_ cider-pprint-fn)))
+    (_ cider-print-fn)))
 
-(defvar cider--pprint-options-mapping
+(defvar cider--print-options-mapping
   '((right-margin
      ((fipp . width) (puget . width) (zprint . width)))
     (length
@@ -268,35 +270,49 @@ Set to nil for no limit."
      ((fipp . print-level) (puget . print-level) (zprint . max-depth))))
   "A mapping of print option for the various supported print engines.")
 
-(defun cider--pprint-option (name printer)
-  "Covert the generic NAME to its PRINTER specific variant.
+(defun cider--print-option (name printer)
+  "Convert the generic NAME to its PRINTER specific variant.
 E.g. pprint's right-margin would become width for fipp.
 The function is useful when you want to generate dynamically
 print options.
 
 NAME can be a string or a symbol.  PRINTER has to be a symbol.
 The result will be a string."
   (let* ((name (cider-maybe-intern name))
-         (result (cdr (assoc printer (cadr (assoc name cider--pprint-options-mapping))))))
+         (result (cdr (assoc printer (cadr (assoc name cider--print-options-mapping))))))
     (symbol-name (or result name))))
 
-(defun cider--nrepl-pprint-request-plist (right-margin &optional pprint-fn)
-  "Plist to be appended to an eval request to make it use pprint.
-PPRINT-FN is the name of the Clojure function to use.
-RIGHT-MARGIN specifies the maximum column-width of the pretty-printed
-result, and is included in the request if non-nil."
-  (let* ((print-options (or cider-pprint-options (nrepl-dict))))
-    (when right-margin
-      (setq print-options (nrepl-dict-put print-options (cider--pprint-option "right-margin" cider-pprint-fn) right-margin)))
-    (append `("nrepl.middleware.print/print" ,(or pprint-fn (cider--pprint-fn))
-              "nrepl.middleware.print/stream?" "1")
-            (when cider-print-quota
-              `("nrepl.middleware.print/quota" ,cider-print-quota))
-            (and (not (nrepl-dict-empty-p print-options)) `("nrepl.middleware.print/options" ,print-options)))))
-
-(defun cider--nrepl-content-type-plist ()
-  "Plist to be appended to an eval request to make it use content-types."
-  '("content-type" "true"))
+(defun cider--nrepl-print-request-map (&optional right-margin)
+  "Map to merge into requests that require pretty-printing.
+RIGHT-MARGIN specifies the maximum column-width of the printed result, and
+is included in the request if non-nil."
+  (let* ((width-option (cider--print-option "right-margin" cider-print-fn))
+         (print-options (thread-last
+                            (map-merge 'hash-table
+                                       `((,width-option ,right-margin))
+                                       cider-print-options)
+                          (map-pairs)
+                          (seq-mapcat #'identity)
+                          (apply #'nrepl-dict))))
+    (map-merge 'list
+               `(("nrepl.middleware.print/print" ,(cider--print-fn))
+                 ("nrepl.middleware.print/stream?" "1"))
+               (when cider-print-quota
+                 `(("nrepl.middleware.print/quota" ,cider-print-quota)))
+               (unless (nrepl-dict-empty-p print-options)
+                 `(("nrepl.middleware.print/options" ,print-options))))))
+
+(defun cider--nrepl-pr-request-map ()
+  "Map to merge into requests that do not require pretty printing."
+  (map-merge 'list
+             `(("nrepl.middleware.print/print" "cider.nrepl.pprint/pr"
+                "nrepl.middleware.print/stream?" nil))
+             (when cider-print-quota
+               `(("nrepl.middleware.print/quota" ,cider-print-quota)))))
+
+(defun cider--nrepl-content-type-map ()
+  "Map to be merged into an eval request to make it use content-types."
+  '(("content-type" "true")))
 
 (defun cider-tooling-eval (input callback &optional ns connection)
   "Send the request INPUT to CONNECTION and register the CALLBACK.
@@ -595,10 +611,13 @@ The result entries are relative to the classpath."
 
 (defun cider-sync-request:format-edn (edn right-margin)
   "Perform \"format-edn\" op with EDN and RIGHT-MARGIN."
-  (let* ((response (thread-first `("op" "format-edn"
-                                   "edn" ,edn)
-                     (append (cider--nrepl-pprint-request-plist right-margin))
-                     (cider-nrepl-send-sync-request)))
+  (let* ((request (thread-last
+                      (map-merge 'list
+                                 `(("op" "format-edn")
+                                   ("edn" ,edn))
+                                 (cider--nrepl-print-request-map right-margin))
+                    (seq-mapcat #'identity)))
+         (response (cider-nrepl-send-sync-request request))
          (err (nrepl-dict-get response "err")))
     (when err
       ;; err will be a stacktrace with a first line that looks like:

cider-debug.el

@@ -25,18 +25,21 @@
 
 ;;; Code:
 
-(require 'nrepl-dict)
-(require 'nrepl-client) ; `nrepl--mark-id-completed'
-(require 'cider-eval)
+(require 'map)
+(require 'seq)
+(require 'subr-x)
+
+(require 'spinner)
+
+(require 'cider-browse-ns)
 (require 'cider-client)
-(require 'cider-util)
+(require 'cider-eval)
 (require 'cider-inspector)
-(require 'cider-browse-ns)
+(require 'cider-util)
 (require 'cider-common)
-(require 'subr-x)
 (require 'cider-compat)
-(require 'seq)
-(require 'spinner)
+(require 'nrepl-client) ; `nrepl--mark-id-completed'
+(require 'nrepl-dict)
 
 
 ;;; Customization
@@ -103,13 +106,7 @@ configure `cider-debug-prompt' instead."
 
 (make-obsolete 'cider-debug-print-length 'cider-debug-print-options "0.20")
 (make-obsolete 'cider-debug-print-level 'cider-debug-print-options "0.20")
-
-(defcustom cider-debug-print-options '(dict "length" 10 "level" 10)
-  "The print options for values displayed by the debugger.
-This variable must be set before starting the repl connection."
-  :type 'listp
-  :group 'cider-stacktrace
-  :package-version '(cider . "0.20.0"))
+(make-obsolete-variable 'cider-debug-print-options 'cider-print-options "0.21")
 
 
 ;;; Implementation
@@ -156,9 +153,11 @@ This variable must be set before starting the repl connection."
 (defun cider--debug-init-connection ()
   "Initialize a connection with the cider.debug middleware."
   (cider-nrepl-send-request
-   (nconc '("op" "init-debugger")
-          (when cider-debug-print-options
-            `("print-options" ,cider-debug-print-options)))
+   (thread-last
+       (map-merge 'list
+                  '(("op" "init-debugger"))
+                  (cider--nrepl-print-request-map fill-column))
+     (seq-mapcat #'identity))
    #'cider--debug-response-handler))