ledger/lisp/ldg-auto.el
2013-02-22 21:07:11 -07:00

187 lines
6.5 KiB
EmacsLisp

;;; ldg-auto.el --- Helper code for use with the "ledger" command-line tool
;; Copyright (C) 2013 Craig Earls (enderw88 at gmail dot com)
;; This file is not part of GNU Emacs.
;; This 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 2, or (at your option)
;; any later version.
;;
;; This 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 Emacs; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Commentary:
;;
;; This module provides or automatically adding transactions to a
;; ledger buffer on a periodic basis. h Recurrence expressions are
;; inspired by Martin Fowler's "Recurring Events for Calendars",
;; martinfowler.com/apsupp/recurring.pdf
;; use (fset 'VARNAME (macro args)) to put the macro definition in the
;; function slot of the symbol VARNAME. Then use VARNAME as the
;; function without have to use funcall.
(defsubst between (val low high)
(and (>= val low) (<= val high)))
(defun ledger-auto-days-in-month (month year)
"Return number of days in the MONTH, MONTH is form 1 to 12"
(if (between month 1 12)
(if (and (date-leap-year-p year) (= 2 month))
29
(nth (1- month) '(31 28 31 30 31 30 31 31 30 31 30 31)))
(error "Month out of range, MONTH=%S" month)))
;; Macros to handle date expressions
(defmacro ledger-auto-day-in-month-macro (count day-of-week)
"Return a form that evaluates DATE that returns true for the COUNT DAY-OF-WEEK.
For example, return true if date is the 3rd Thursday of the
month. Negative COUNT starts from the end of the month. (EQ
COUNT 0) means EVERY day-of-week (eg. every Saturday)"
(if (and (between count -6 6) (between day-of-week 0 6))
(cond ((zerop count) ;; Return true if day-of-week matches
`(eq (nth 6 (decode-time date)) ,day-of-week))
((> count 0) ;; Positive count
(let ((decoded (gensym)))
`(let ((,decoded (decode-time date)))
(if (and (eq (nth 6 ,decoded) ,day-of-week)
(between (nth 3 ,decoded)
,(* (1- count) 7)
,(* count 7)))
t
nil))))
((< count 0)
(let ((days-in-month (gensym))
(decoded (gensym)))
`(let* ((,decoded (decode-time date))
(,days-in-month (ledger-auto-days-in-month
(nth 4 ,decoded)
(nth 5 ,decoded))))
(if (and (eq (nth 6 ,decoded) ,day-of-week)
(between (nth 3 ,decoded)
(+ ,days-in-month ,(* count 7))
(+ ,days-in-month ,(* (1+ count) 7))))
t
nil))))
(t
(error "COUNT out of range, COUNT=%S" count)))
(error "Invalid argument to ledger-auto-day-in-month-macro %S %S"
count
day-of-week)))
(defmacro ledger-auto-day-of-month-macro (day)
"Return a form of date that returns true for the DAY of the month.
For example, return true if date is the 23rd of the month."
`(if (eq (nth 3 (decode-time date)) ,day)
t))
(defmacro ledger-auto-month-of-year-macro (month)
"Return a form of date that returns true for the MONTH of the year.
For example, return true if date is the 4th month of the year."
`(if (eq (nth 4 (decode-time date)) ,month)
t))
(defmacro ledger-auto-every-count-day-macro (day-of-week skip start-date)
"Return a form that is true for every DAY skipping SKIP, starting on START.
For example every second Friday, regardless of month."
(let ((start-day (nth 6 (decode-time (eval start-date)))))
(if (eq start-day day-of-week) ;; good, can proceed
`(if (zerop (mod (- (time-to-days date) ,(time-to-days (eval start-date))) ,(* skip 7)))
t
nil)
(error "START-DATE day of week doesn't match DAY-OF-WEEK"))))
(defmacro ledger-auto-date-range-macro (month1 day1 month2 day2)
"Return a form of DATE that is true if DATE falls between MONTH1 DAY1 and MONTH2 DAY2."
(let ((decoded (gensym))
(target-month (gensym))
(target-day (gensym)))
`(let* ((,decoded (decode-time date))
(,target-month (nth 4 decoded))
(,target-day (nth 3 decoded)))
(and (and (> ,target-month ,month1)
(< ,target-month ,month2))
(and (> ,target-day ,day1)
(< ,target-day ,day2))))))
(defun ledger-auto-is-holiday (date)
"Return true if DATE is a holiday.")
(defun ledger-auto-scan-transactions (auto-file)
(let ((xact-list (list)))
(save-excursion
(find-file auto-file)
(goto-char (point-min))
(while (re-search-forward "^\\[\\(.*\\)\\] " nil t)
(let ((date-descriptor "")
(transaction nil)
(xact-start (match-end 0)))
(setq date-descriptors
(ledger-auto-read-descriptor-tree
(buffer-substring-no-properties
(match-beginning 0)
(match-end 0))))
(forward-paragraph)
(setq transaction (list date-descriptors
(buffer-substring-no-properties
xact-start
(point))))
(setq xact-list (cons transaction xact-list))))
xact-list)))
(defun ledger-auto-read-descriptor-tree (descriptor-string)
"Take a date descriptor string and return a function that
returns true if the date meets the requirements"
(with-temp-buffer
(let (pos)
(insert descriptor-string)
(goto-char (point-min))
(replace-string "[" "(")
(goto-char (point-min))
(replace-string "]" ")")
(goto-char (point-max))
(while (re-search-backward
(concat "\\([0-9]+\\|[\*]\\)/" ;; Year slot
"\\([\*EO]\\|[0-9]+\\)/" ;; Month slot
"\\([\*]\\|\\([0-9][0-9]\\)\\|"
"\\([0-5]"
"\\(\\(Su\\)\\|"
"\\(Mo\\)\\|"
"\\(Tu\\)\\|"
"\\(We\\)\\|"
"\\(Th\\)\\|"
"\\(Fr\\)\\|"
"\\(Sa\\)\\)\\)\\)") nil t) ;; Day slot
(goto-char
(match-end 0))
(insert ?\")
(goto-char (match-beginning 0))
(insert "\"" )))
(ledger-auto-traverse-descriptor-tree
(read (buffer-substring (point-min) (point-max))) 0)))
(defun ledger-auto-traverse-descriptor-tree (tree depth)
(dolist (node tree)
(cond ((eq (type-of node) 'string)
(ledger-auto-parse-date-descriptor node))
((eq (type-of node) 'cons)
(ledger-auto-traverse-descriptor-tree node (1+ depth))))))
(defun ledger-auto-parse-date-descriptor (descriptor)
"Parse the date descriptor, return the evaluator"
descriptor)
(provide 'ldg-auto)
;;; ldg-auto.el ends here