From a5c62acec9574dab270f9c2f78cb4ff49272b6fc Mon Sep 17 00:00:00 2001
From: Noriyuki OHKAWA <n.ohkawa@asahinet.com>
Date: Fri, 4 Apr 2014 23:52:09 +0900
Subject: [PATCH] display error message to minibuffer when goto next/prev
 error.

---
 elisp/ghc-check.el | 22 ++++++++++++++++++++++
 elisp/ghc.el       | 19 +++++++++++++++++--
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/elisp/ghc-check.el b/elisp/ghc-check.el
index 07595d0..ae86d1a 100644
--- a/elisp/ghc-check.el
+++ b/elisp/ghc-check.el
@@ -144,6 +144,18 @@
 	 (insert (overlay-get (car ovls) 'ghc-file) "\n\n")
 	 (mapc (lambda (x) (insert x "\n\n")) errs))))))
 
+(defun ghc-display-errors-to-minibuf ()
+  (interactive)
+  (let* ((ovls (ghc-check-overlay-at (point)))
+	 (errs (mapcar (lambda (ovl) (overlay-get ovl 'ghc-msg)) ovls))
+         (old-max-mini-window-height max-mini-window-height))
+    (setq max-mini-window-height 0.95)
+    (if (null ovls)
+	(message "No errors or warnings")
+      (progn
+        (message "%s\n" (mapconcat (lambda (x) (replace-regexp-in-string "\0" "\n" x)) errs "\n"))))
+    (setq old-max-mini-window-height)))
+
 (defun ghc-check-overlay-at (p)
   (let ((ovls (overlays-at p)))
     (ghc-filter (lambda (ovl) (overlay-get ovl 'ghc-check)) ovls)))
@@ -160,6 +172,11 @@
 	 (pnts (mapcar 'overlay-start ovls2)))
     (if pnts (goto-char (apply 'max pnts)))))
 
+(defun ghc-goto-and-display-prev-error ()
+  (interactive)
+  (ghc-goto-prev-error)
+  (ghc-display-errors-to-minibuf))
+
 (defun ghc-goto-next-error ()
   (interactive)
   (let* ((here (point))
@@ -170,6 +187,11 @@
 	 (pnts (mapcar 'overlay-start ovls2)))
     (if pnts (goto-char (apply 'min pnts)))))
 
+(defun ghc-goto-and-display-next-error ()
+  (interactive)
+  (ghc-goto-next-error)
+  (ghc-display-errors-to-minibuf))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (defun ghc-check-insert-from-warning ()
diff --git a/elisp/ghc.el b/elisp/ghc.el
index c29bc34..c3c1f6c 100644
--- a/elisp/ghc.el
+++ b/elisp/ghc.el
@@ -8,6 +8,14 @@
 ;;
 ;; (autoload 'ghc-init "ghc" nil t)
 ;; (add-hook 'haskell-mode-hook (lambda () (ghc-init)))
+;;
+;; Or you wish to display error to minibuffer.
+;;
+;; (autoload 'ghc-init "ghc" nil t)
+;; (setq ghc-display-error-to-minibuffer t)
+;; (add-hook 'haskell-mode-hook (lambda () (ghc-init)))
+
+;;
 
 ;;; Code:
 
@@ -56,6 +64,8 @@
 (defvar ghc-shallower-key   "\C-c<")
 (defvar ghc-deeper-key      "\C-c>")
 
+(defvar ghc-display-error-to-minibuffer  nil)
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;
 ;;; Initializer
@@ -74,8 +84,13 @@
     (define-key haskell-mode-map ghc-info-key        'ghc-show-info)
     (define-key haskell-mode-map ghc-expand-key      'ghc-expand-th)
     (define-key haskell-mode-map ghc-import-key      'ghc-import-module)
-    (define-key haskell-mode-map ghc-previous-key    'ghc-goto-prev-error)
-    (define-key haskell-mode-map ghc-next-key        'ghc-goto-next-error)
+    (if ghc-display-error-to-minibuffer
+        (progn
+          (define-key haskell-mode-map ghc-previous-key    'ghc-goto-and-display-prev-error)
+          (define-key haskell-mode-map ghc-next-key        'ghc-goto-and-display-next-error))
+      (progn
+        (define-key haskell-mode-map ghc-previous-key    'ghc-goto-prev-error)
+        (define-key haskell-mode-map ghc-next-key        'ghc-goto-next-error)))
     (define-key haskell-mode-map ghc-help-key        'ghc-display-errors)
     (define-key haskell-mode-map ghc-insert-key      'ghc-insert-template)
     (define-key haskell-mode-map ghc-sort-key        'ghc-sort-lines)