power-query-mode.el

;;; power-query-mode.el --- sample major mode for editing queries in the power query language. -*- coding: utf-8; lexical-binding: t; -*-

;; Copyright © 2019, by Alf Lervåg

;; Author: Alf Lervåg (alf@lervag.net)
;; Version: 1.0.0
;; Created: 28 Nov 2019
;; Keywords: languages

;; This file is not part of GNU Emacs.

;;; License:

;; You can redistribute this program and/or modify it under the terms of the GNU General Public License version 2.

;;; Commentary:

;; short description here

;; full doc on how to use here

;;; Code:

;; create the list for font-lock.
;; each category of keyword is given a particular face
(setq power-query-font-lock-keywords
      (let* (
             ;; define several category of keywords
             (x-keywords '("let" "if" "else" "then" "each" "error" "in" "type"))
             (x-types '("date" "datetime"))
             (x-functions '("Table.TransformColumnTypes"))

             ;; generate regex string for each category of keywords
             (x-keywords-regexp (regexp-opt x-keywords 'words))
             (x-types-regexp (regexp-opt x-types 'words))
             (x-functions-regexp (regexp-opt x-functions 'words)))

        `(
          (,x-types-regexp . font-lock-type-face)
          (,x-functions-regexp . font-lock-function-name-face)
          (,x-keywords-regexp . font-lock-keyword-face)
          ;; note: order above matters, because once colored, that part won't change.
          ;; in general, put longer words first
          )))

;;;###autoload
(define-derived-mode power-query-mode prog-mode "power-query mode"
  "Major mode for editing Power Query"

  ;; code for syntax highlighting
  (setq font-lock-defaults '((power-query-font-lock-keywords))))

(defun alf/adler32 (start end)
  "Naive implementation of the Adler 32 checksum algorithm for
padding a deflated stream with zlib headres so we can inflate it
using zlib-decompress-region."
  (save-excursion
    (goto-char (point-min))
    (let* ((a 1)
           (b 0))
      (while (not (eobp))
        (setq a (mod (+ a (char-after)) 65521))
        (setq b (mod (+ b a) 65521))
        (forward-char 1))
      (logior (lsh b 16) a))))

(defun alf/decompress (s)
  (interactive "s")
  (insert (with-temp-buffer
            (toggle-enable-multibyte-characters)
            (goto-char (point-min))
            (insert (base64-decode-string s))
            (insert (alf/adler-as-string (point-min) (point-max)))
            (goto-char (point-min))
            (insert-char #x78)
            (insert-char #x9c)
            (buffer-string))))

(defun alf/adler-as-string (start end)
  "Naive implementation of the Adler 32 checksum algorithm for
padding a deflated stream with zlib headres so we can inflate it
using zlib-decompress-region."
  (save-excursion
    (goto-char (point-min))
    (let* ((a 1)
           (b 0))
      (while (not (eobp))
        (setq a (mod (+ a (char-after)) 65521))
        (setq b (mod (+ b a) 65521))
        (forward-char 1))
      (string (c-int-to-char b) (c-int-to-char a)))))

;; add the mode to the `features' list
(provide 'power-query-mode)

;;; power-query-mode.el ends here