;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix 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 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix 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 Guix.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:
;;;
;;; This script updates the list of new and updated packages in 'NEWS'.
;;;
;;; Code:

(use-modules (gnu) (guix)
             (guix build utils)
             ((guix ui) #:select (fill-paragraph))
             (srfi srfi-1)
             (srfi srfi-11)
             (ice-9 match)
             (ice-9 rdelim)
             (ice-9 regex)
             (ice-9 vlist)
             (ice-9 pretty-print))

(define %header-rx
  (make-regexp "^\\* Changes in (version )?([0-9.]+) \\(since ([0-9.]+)\\)"))

(define (NEWS->versions port)
  "Return two values: the previous version and the current version as read
from PORT, which is an input port on the 'NEWS' file."
  (let loop ()
    (let ((line (read-line port)))
      (cond ((eof-object? line)
             (error "failed to determine previous and current version"
                    port))
            ((regexp-exec %header-rx line)
             =>
             (lambda (match)
               (values (match:substring match 3)
                       (match:substring match 2))))
            (else
             (loop))))))

(define (skip-to-org-heading port)
  "Read from PORT until an Org heading is found."
  (let loop ()
    (let ((next (peek-char port)))
      (cond ((eqv? next #\*)
             #t)
            ((eof-object? next)
             (error "next heading could not be found"))