Add minimal viable code

taskwarrior.el

@@ -0,0 +1,97 @@
+;; Frontend for taskwarrior
+;;
+;; TODO: Implement modeline indicator for deadline and entries
+;; TODO: Update buffer if command modifies the state
+
+(require 'json)
+
+(defgroup taskwarrior nil "An emacs frontend to taskwarrior.")
+
+(defvar taskwarrior-description 'taskwarrior-description
+  "Taskwarrior mode face used for tasks with a priority of C.")
+
+(setq taskwarrior-highlight-regexps
+      `(("^[0-9]*" . font-lock-variable-name-face)
+	("(.*)" . font-lock-builtin-face)
+	("[:space:].*:" . font-lock-function-name-face)))
+
+
+(defvar taskwarrior-mode-map nil "Keymap for `taskwarrior-mode'")
+(progn
+  (setq taskwarrior-mode-map (make-sparse-keymap))
+  (define-key taskwarrior-mode-map (kbd "p") 'previous-line)
+  (define-key taskwarrior-mode-map (kbd "k") 'previous-line)
+  (define-key taskwarrior-mode-map (kbd "n") 'next-line)
+  (define-key taskwarrior-mode-map (kbd "j") 'next-line)
+  (define-key taskwarrior-mode-map (kbd "q") 'quit-window)
+  (define-key taskwarrior-mode-map (kbd "a") 'taskwarrior-add)
+  (define-key taskwarrior-mode-map (kbd "p") 'taskwarrior-change-project))
+
+(defun taskwarrior-id-at-point ()
+  (let ((line (thing-at-point 'line t)))
+    (string-match "^[0-9]*" line)
+    (match-string 0 line)))
+
+(defun taskwarrior--shell-command (command &optional filter modifications miscellaneous)
+  (shell-command-to-string
+   (format "task %s %s %s %s"
+	   (or filter "")
+	   command
+	   (or modifications "")
+	   (or miscellaneous))))
+
+(defun taskwarrior-export (filter)
+  "Export taskwarrior entries as JSON"
+  (let ((filter (concat "id " filter))
+	(command "export"))
+    (json-read-from-string
+     (taskwarrior--shell-command command filter))))
+
+(defun taskwarrior-change-project (project)
+  (interactive "sProject: ")
+  (let ((filter (taskwarrior-id-at-point))
+	(command "modify")
+	(modifications (concat "project:" project)))
+    (taskwarrior--shell-comand command filter modifications)))
+
+(defun taskwarrior-add (description)
+  (interactive "sDescription: ")
+    (taskwarrior--shell-comand "add" "" description))
+
+;; Setup a major mode for taskwarrior
+;;;###autoload
+(define-derived-mode taskwarrior-mode text-mode "taskwarrior"
+  "Major mode for working with taskwarrior. \\{taskwarrior-mode-map}"
+  (setq font-lock-defaults '(taskwarrior-highlight-regexps))
+  (setq goal-column 0)
+  (auto-revert-mode)
+  (setq buffer-read-only t))
+
+;;; externally visible functions
+;;;###autoload
+(defun taskwarrior ()
+  "Open the taskwarrior buffer.  If one already exists, bring it to
+the front and focus it.  Otherwise, create one and load the data."
+  (interactive)
+  (let* ((buf (get-buffer-create "taskwarrior")))
+    (progn
+      (switch-to-buffer buf)
+      (setq font-lock-defaults '(taskwarrior-highlight-regexps))
+      (toggle-read-only)
+      (goto-char (point-min))
+      (erase-buffer)
+      (taskwarrior-write-entries)
+      (taskwarrior-mode)
+      (while (not (equal (overlays-at (point)) nil))
+	(forward-char)))))
+
+(defun taskwarrior-write-entries ()
+  (let ((entries (append (taskwarrior-export "context:personal") nil)))
+    (dolist (entry entries)
+      (progn
+	(insert (format
+		 "%-2d (%0.2f) %s: %s?\n"
+		 (alist-get 'id entry)
+		 (alist-get 'urgency entry)
+		 (alist-get 'project entry)
+		 (alist-get 'description entry)))))))