haskell-add-import-line

haskell-add-import-line.el

(defvar module-abbrevs nil)
(setq module-abbrevs '(("Text"
                             "Data.Text (Text)"
                             "qualified Data.Text as Text")
                         ("Encoding" "qualified Data.Text.Encoding as Text")
                         ("Map"  "qualified Data.Map as Map"
                                 "Data.Map (Map)"
                                 )
                         ("Set" "Data.Set (Set)"
                                "qualified Data.Set as Set")
                         ("App"  "Control.Applicative")
                         ("Monad" "Control.Monad")
                         ("BS"   "qualified Data.ByteString as BS"
                                 "Data.ByteString (ByteString)")
                         ("BS8"  "qualified Data.ByteString.Char8 as BS8")
                         ("BSL"  "qualified Data.ByteString.Lazy as BSL")
                         ("Concurrent" "Control.Concurrent")
                         ("STM" "Control.Concurrent.STM")
                         ("Xmpp" "qualified Network.Xmpp as Xmpp")
                         ("XML" "qualified Data.XML.Types as XML")
                         ("Ex" "qualified Control.Exception as Ex")
                         ("Monoid" "Data.Monoid")
                         ("Function" "Data.Function")
                         ("Ord" "Data.Ord")
                         ("Char" "Data.Char")
                         ("List" "qualified Data.List as List")
                         ("IO" "Control.Monad.IO.Class")
                         ("STM" "Control.Concurrent.STM")
                         ("IORef" "Data.IORef")
                         ("UUID" "Data.UUID (UUID)"
                                 "qualified Data.UUID as UUID")
                         ))

(defun haskell-exists-import-line (line)
  (save-excursion
    (beginning-of-buffer)
    (not (not (re-search-forward (concat "^" "import[ ]*" line "$")
                                 (point-max) t)))))

(defun haskell-add-import-lines (import-line)
  "Add an import line to the current buffer.

   import-line can be an abbreviation defined in the
   module-abbrevs variable. If this is the case, all the elements
   in the matching entry are inserted (no further expansion
   is performed)

   If no abbreviation entry matches, the input it is inserted verbatim

   Prefixing the input with an exclamation mark (!) forces the
   rest of the input to be treated as an abbreviation. An error
   is thrown when the given string doesn't match any entry
  "
  (interactive "Mmodules: ")
  (require 'haskell-align-imports)
  (require 'haskell-sort-imports)
  (save-excursion
    (let* ((force-abbrev (string= (substring import-line 0 1) "!"))
           (import (if force-abbrev (substring import-line 1) import-line))
           (decls (or (cdr (assoc import module-abbrevs))
                      (when force-abbrev
                        (error "Module abbreviation \"%s\" not found" import))
                      (list import))))
      (mapc (lambda (decl)
                      (unless (haskell-exists-import-line decl)
                        (beginning-of-buffer)
                        (haskell-navigate-imports)
                        (insert (concat "import " decl "\n"))))
                    decls)
      (haskell-sort-imports)
      (haskell-align-imports))))