Tidy up haskell-present and haskell-process-do-simple-echo

Simplify `haskell-present`:

+ do not apply text properties to hint and fontification to buffer,
  because  presentaions are fontified according to haskell mode
  automatically
+ properly assing presentation buffer to haskell session
+ make buffer readonly

Rename `haskell-process-do-simple-echo` to
`haskell-process-show-repl-response` and remove redundant mode argument

Update doc strings

Author: geraldus

haskell-commands.el

@@ -300,7 +300,7 @@ If PROMPT-VALUE is non-nil, request identifier via mini-buffer."
                                   (or ident
                                       at-point))))))
         (when command
-          (haskell-process-do-simple-echo command 'haskell-mode))))))
+          (haskell-process-show-repl-response command))))))
 
 ;;;###autoload
 (defun haskell-process-do-type (&optional insert-value)
@@ -318,14 +318,13 @@ If PROMPT-VALUE is non-nil, request identifier via mini-buffer."
       ;; No newlines in expressions, and surround with parens if it
       ;; might be a slice expression
       (when expr-okay
-        (haskell-process-do-simple-echo
+        (haskell-process-show-repl-response
          (format
           (if (or (string-match-p "\\`(" expr)
-                 (string-match-p "\\`[_[:alpha:]]" expr))
+                  (string-match-p "\\`[_[:alpha:]]" expr))
               ":type %s"
             ":type (%s)")
-          expr)
-         'haskell-mode)))))
+          expr))))))
 
 ;;;###autoload
 (defun haskell-mode-jump-to-def-or-tag (&optional next-p)

haskell-interactive-mode.el

@@ -1094,30 +1094,23 @@ don't care when the thing completes as long as it's soonish."
                           'rear-nonsticky t)))))
 
 ;;;###autoload
-(defun haskell-process-do-simple-echo (line &optional mode)
-  "Send LINE to the GHCi process and echo the result in some
-fashion, such as printing in the minibuffer, or using
-haskell-present, depending on configuration."
+(defun haskell-process-show-repl-response (line)
+  "Send LINE to the GHCi process and echo the result in some fashion.
+Result will be printed in the minibuffer or presented using
+haskell-present, depending on variable `haskell-process-use-presentation-mode'."
   (let ((process (haskell-interactive-process)))
     (haskell-process-queue-command
      process
      (make-haskell-command
-      :state (list process line mode)
+      :state (cons process line)
       :go (lambda (state)
-            (haskell-process-send-string (car state) (cadr state)))
+            (haskell-process-send-string (car state) (cdr state)))
       :complete (lambda (state response)
-                  ;; TODO: TBD: don't do this if
-                  ;; `haskell-process-use-presentation-mode' is t.
-                  (haskell-interactive-mode-echo
-                   (haskell-process-session (car state))
-                   (replace-regexp-in-string "\n\\'" "" response)
-                   (cl-caddr state))
                   (if haskell-process-use-presentation-mode
-                      (progn (haskell-present (cadr state)
-                                              (haskell-process-session (car state))
-                                              response)
-                             (haskell-session-assign
-                              (haskell-process-session (car state))))
+                      (haskell-present
+                       (cdr state)
+                       (haskell-process-session (car state))
+                       response)
                     (haskell-mode-message-line response)))))))
 
 (provide 'haskell-interactive-mode)

haskell-presentation-mode.el

@@ -26,6 +26,7 @@
 ;;; Code:
 
 (require 'haskell-mode)
+(require 'haskell-session)
 
 (define-derived-mode haskell-presentation-mode
   haskell-mode "Presentation"
@@ -36,23 +37,25 @@
 (define-key haskell-presentation-mode-map (kbd "q") 'quit-window)
 
 (defun haskell-present (name session code)
-  "Present CODE in a popup buffer suffixed with NAME and set
-SESSION as the current haskell-session."
-  (let* ((name (format "*Haskell Presentation%s*" name))
-         (buffer (get-buffer-create name)))
+  "Present given code in a popup buffer.
+Creates temporal buffer with given NAME and assigns it to given
+haskell SESSION; presented CODE will be fontified as haskell code."
+  (let ((buffer (get-buffer-create name)))
     (with-current-buffer buffer
       (haskell-presentation-mode)
-      (if (boundp 'shm-display-quarantine)
-          (set (make-local-variable 'shm-display-quarantine) nil))
-      (let ((buffer-read-only nil))
+
+      (when (boundp 'shm-display-quarantine)
+        (set (make-local-variable 'shm-display-quarantine) nil))
+
+      (let ((buffer-read-only nil)
+            (hint "-- Hit `q' to close this window.\n\n"))
+        (haskell-session-assign session)
         (erase-buffer)
-        (insert (propertize "-- Hit `q' to close this window.\n\n"
-                            'face
-                            'font-lock-comment-face))
-        (let ((point (point)))
-          (insert code "\n\n")
-          (font-lock-fontify-region point (point))
-          (goto-char point))))
+        (insert hint)
+        (save-excursion
+          (insert code "\n\n")))
+      (setq buffer-read-only t))
+
     (if (eq major-mode 'haskell-presentation-mode)
         (switch-to-buffer buffer)
       (pop-to-buffer buffer))))