vms/make-mms-derivative.el

   1 ;;; make-mms-derivative.el --- framework to do horrible things for VMS support
   2
   3 ;; Copyright (C) 2005, 2006 Free Software Foundation, Inc.
   4
   5 ;; Author: Thien-Thi Nguyen <ttn@gnu.org>
   6 ;; Keywords: maint build vms mms makefile levitte autoconf war-is-a-lose
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  22 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  23 ;; Boston, MA 02110-1301, USA.
  24
  25 ;;; Commentary:
  26
  27 ;; Under VMS the standard make-like program is called MMS, which looks
  28 ;; for an input file in the default directory named DESCRIP.MMS and runs
  29 ;; the DCL command rules therein.  As of 2005, the build process
  30 ;; requires a hand translation of the Makefile.in and Emacs-specific
  31 ;; methodology to DCL and TPU commands, so to alleviate this pain, we
  32 ;; provide `make-mms-derivative', which given a source FILENAME, inserts
  33 ;; the file contents in a new buffer and loads FILENAME-2mms.  The lisp
  34 ;; code in the -2mms file can (do whatever -- it's emacs -- and), as
  35 ;; long as it arranges to write out the modified buffer after loading by
  36 ;; specifying, on a line of its own, the directive:
  37 ;;
  38 ;;  :output RELATIVE-OUTPUT
  39 ;;
  40 ;; where RELATIVE-OUTPUT is a filename (a string) relative to FILENAME's
  41 ;; directory, typically something simple like "descrip.mms_in_in".  Only
  42 ;; the first :output directive is recognized.
  43 ;;
  44 ;; The only other special directive at this time has the form:
  45 ;;
  46 ;;  :gigo NAME
  47 ;;  ;;blah blah blah
  48 ;;  ;;(more text here)
  49 ;;
  50 ;; NAME is anything distinguishable w/ `eq' (number, symbol or keyword).
  51 ;; This associates NAME with the block of text starting immediately below
  52 ;; the :gigo directive and ending at the first line that does not begin
  53 ;; with two semicolons (which are stripped from each line in the block).
  54 ;; To insert this block of text, pass NAME to `make-mms-derivative-gigo'.
  55 ;;
  56 ;; Directives are scanned before normal evaluation, so their placement
  57 ;; in the file is not important.  During loading, plain strings are
  58 ;; displayed in the echo area, prefixed with the current line number.
  59 ;;
  60 ;; Over the long run, the convenience functions provided (see source)
  61 ;; will be augmented by factoring maximally the -2mms files, squeezing
  62 ;; as much algorithm out of those nasty heuristics as possible.  What
  63 ;; makes them nasty is not that they rely on the conventions of the
  64 ;; Emacs makefiles; that's no big deal.  What makes them nasty is that
  65 ;; they rely on the conventions of separately maintained tools (namely
  66 ;; Autoconf for VMS and GNU Autoconf), and the separation of conventions
  67 ;; is how people drift apart, dragging their software behind
  68 ;; mercilessly.
  69 ;;
  70 ;; In general, codified thought w/o self-synchronization is doomed.
  71 ;; That a generation would eat its young (most discriminatingly, even)
  72 ;; is no reason GNU cannot build around such woe.
  73
  74 ;;; Code:
  75
  76 (defvar make-mms-derivative-data nil
  77   "Plist of data specific to `make-mms-derivative'.")
  78
  79 (defun make-mms-derivative-data (key &optional newval)
  80   (if newval (setq make-mms-derivative-data
  81                    (plist-put make-mms-derivative-data key newval))
  82     (plist-get make-mms-derivative-data key)))
  83
  84 (defun make-mms-derivative-gigo (name)
  85   "Insert the text associated with :gigo NAME."
  86   (insert (cdr (assq name (make-mms-derivative-data :gigo)))))
  87
  88 (defun make-mms-derivative (filename)
  89   "Take FILENAME contents, load FILENAME-2mms, and write out the result.
  90 The output file is specified by the :output directive in FILENAME-2mms.
  91 See commentary of make-mms-derivative.el for full documentation."
  92   (interactive "fSource File: ")
  93   (let* ((todo (let ((fn (concat filename "-2mms")))
  94                  (unless (file-exists-p fn)
  95                    (error "Could not find %s" fn))
  96                  (set-buffer (get-buffer-create " *make-mms-derivative todo*"))
  97                  (insert-file-contents fn)
  98                  (current-buffer)))
  99          (deriv (get-buffer-create (format "*mms-derivative: %s"
 100                                            (file-relative-name filename))))
 101          output gigo form)
 102     (set-buffer todo)
 103     (re-search-forward "^:output")
 104     (setq output (expand-file-name (read (current-buffer))
 105                                    (file-name-directory filename)))
 106     (goto-char (point-min))
 107     (while (re-search-forward "^:gigo" (point-max) t)
 108       (let ((name (read (current-buffer)))
 109             (p (progn (forward-line 1) (point))))
 110         (while (looking-at ";;")
 111           (delete-char 2)
 112           (forward-line 1))
 113         (setq gigo (cons (cons name (buffer-substring p (point))) gigo))
 114         (delete-region p (point))))
 115     (message "Munging...")
 116     (switch-to-buffer deriv)
 117     (erase-buffer)
 118     (insert-file-contents filename)
 119     (set (make-local-variable 'make-mms-derivative-data)
 120          (list :gigo gigo))
 121     (set-buffer todo)
 122     (goto-char (point-min))
 123     (while (condition-case nil
 124                (setq form (read (current-buffer)))
 125              (end-of-file nil))
 126       (if (stringp form)
 127           (message "%d: %s" (count-lines (point-min) (point)) form)
 128         (save-excursion
 129           (set-buffer deriv)
 130           (eval form))))
 131     (set-buffer deriv)
 132     (message "Munging...done")
 133     (write-file output)
 134     (kill-buffer todo)
 135     (kill-buffer deriv)))
 136
 137 (provide 'make-mms-derivative)
 138
 139 ;;; arch-tag: a5b08625-3952-4053-be16-296220e27bb0
 140 ;;; make-mms-derivative.el ends here