M-C-t for showing type.

elisp/Makefile

@@ -1,4 +1,5 @@
-SRCS = ghc.el ghc-func.el ghc-doc.el ghc-comp.el ghc-flymake.el ghc-command.el
+SRCS = ghc.el ghc-func.el ghc-doc.el ghc-comp.el ghc-flymake.el \
+       ghc-command.el ghc-info.el
 EMACS = emacs
 
 TEMPFILE  = temp.el

elisp/ghc-info.el

@@ -0,0 +1,23 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;
+;;; ghc-info.el
+;;;
+
+;; Author:  Kazu Yamamoto <Kazu@Mew.org>
+;; Created: Nov 15, 2010
+
+;;; Code:
+
+(require 'ghc-func)
+
+(defun ghc-show-type ()
+  (interactive)
+  (if (not (ghc-which ghc-module-command))
+      (message "%s not found" ghc-module-command)
+    (let ((expr (thing-at-point 'symbol))
+	  (file (buffer-name)))
+      (with-temp-buffer
+	(call-process ghc-module-command nil t nil "type" file expr)
+	(message (buffer-substring (point-min) (1- (point-max))))))))
+
+(provide 'ghc-info)

elisp/ghc.el

@@ -23,6 +23,7 @@
 
 (require 'ghc-comp)
 (require 'ghc-doc)
+(require 'ghc-info)
 (require 'ghc-flymake)
 (require 'ghc-command)
 (require 'dabbrev)
@@ -40,6 +41,7 @@
 (defvar ghc-help-key        "\e?")
 (defvar ghc-insert-key      "\et")
 (defvar ghc-sort-key        "\es")
+(defvar ghc-type-key        "\e\C-t")
 (defvar ghc-check-key       "\C-x\C-s")
 (defvar ghc-toggle-key      "\C-c\C-c")
 
@@ -55,6 +57,7 @@
   (unless ghc-initialized
     (define-key haskell-mode-map ghc-completion-key  'ghc-complete)
     (define-key haskell-mode-map ghc-document-key    'ghc-browse-document)
+    (define-key haskell-mode-map ghc-type-key        'ghc-show-type)
     (define-key haskell-mode-map ghc-import-key      'ghc-import-module)
     (define-key haskell-mode-map ghc-previous-key    'flymake-goto-prev-error)
     (define-key haskell-mode-map ghc-next-key        'flymake-goto-next-error)