Completions package

Makefile

@@ -47,6 +47,7 @@ ELFILES = \
 	haskell-compat.el \
 	haskell-compile.el \
 	haskell-complete-module.el \
+	haskell-completions.el \
 	haskell-customize.el \
 	haskell-debug.el \
 	haskell-decl-scan.el \

haskell-completions.el

@@ -0,0 +1,46 @@
+;;; haskell-completions.el --- Haskell Completion package
+
+;; Copyright © 2015 Athur Fayzrakhmanov. All rights reserved.
+
+;; This file is part of haskell-mode package.
+;; You can contact with authors using GitHub issue tracker:
+;; https://github.com/haskell/haskell-mode/issues
+
+;; This file is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
+
+;; This file is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
+
+;;; Commentary:
+
+;; This package provides completions related functionality for
+;; Haskell Mode such grab completion prefix at point, and etc..
+
+;;; Code:
+
+(defun haskell-completions-can-grab-prefix ()
+  "Check if the case is appropriate for grabbing completion prefix.
+Returns t if point is either at whitespace character, or at
+punctuation, or at line end and preceeding character is not a
+whitespace or new line, otherwise returns nil.
+
+  Returns nil in presense of active region."
+  (when (not (region-active-p))
+    (when (looking-at (rx (| space line-end punct)))
+      (when (not (bobp))
+        (save-excursion
+          (backward-char)
+          (not (looking-at (rx (| space line-end)))))))))
+
+(provide 'haskell-completions)
+;;; haskell-completions.el ends here

tests/haskell-completions-tests.el

@@ -0,0 +1,74 @@
+;;; haskell-completions-tests.el --- Tests for Haskell Completion package
+
+;; Copyright © 2015 Athur Fayzrakhmanov. All rights reserved.
+
+;; This file is part of haskell-mode package.
+;; You can contact with authors using GitHub issue tracker:
+;; https://github.com/haskell/haskell-mode/issues
+
+;; This file is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
+
+;; This file is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
+
+;;; Commentary:
+
+;; This package provides regression tests for haskell-completions package.
+
+;;; Code:
+
+(require 'ert)
+(require 'haskell-mode)
+(require 'haskell-completions)
+
+
+(ert-deftest haskell-completions-can-grab-prefix-test ()
+  "Tests the function `haskell-completions-can-grab-prefix'."
+  (with-temp-buffer
+    (haskell-mode)
+    (should (eql nil (haskell-completions-can-grab-prefix)))
+    (insert " ")
+    (should (eql nil (haskell-completions-can-grab-prefix)))
+    (insert "a")
+    (should (eql t (haskell-completions-can-grab-prefix)))
+    (save-excursion
+      (insert " ")
+      (should (eql nil (haskell-completions-can-grab-prefix)))
+      (insert "bc-")
+      (should (eql t (haskell-completions-can-grab-prefix)))
+      (insert "\n")
+      (should (eql nil (haskell-completions-can-grab-prefix)))
+      (insert "def:#!")
+      (should (eql t (haskell-completions-can-grab-prefix))))
+    (should (eql t (haskell-completions-can-grab-prefix)))
+    ;; punctuation tests
+    (save-excursion (insert ")"))
+    (should (eql t (haskell-completions-can-grab-prefix)))
+    (save-excursion (insert ","))
+    (should (eql t (haskell-completions-can-grab-prefix)))
+    (save-excursion (insert "'"))
+    (should (eql t (haskell-completions-can-grab-prefix)))
+    ;; should return nil in the middle of word
+    (save-excursion (insert "bcd"))
+    (should (eql nil (haskell-completions-can-grab-prefix)))
+    ;; region case
+    (let ((p (point)))
+      (goto-char (point-min))
+      (push-mark)
+      (goto-char p)
+      (activate-mark)
+      (should (eql nil (haskell-completions-can-grab-prefix))))))
+
+
+(provide 'haskell-completions-tests)
+;;; haskell-completions-tests.el ends here