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tinmop/src/date-formatter.lisp

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Common Lisp

;; tinmop: an humble mastodon client
;; Copyright (C) 2018 cage
;; This program 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.
;; This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
(in-package :date-formatter)
;; FORMAT := (FIELD | TEXT)*
;; FIELD := [%hour %minute %second %month %year %day %weekday %%]
;; TEXT := (not percent)+
(defrule field
(or "%hour"
"%min"
"%second"
"%month"
"%year"
"%day"
"%weekday"
"%short-weekday"
"%long-weekday"
"%long-month"
"%short-month"
"%%")
(:text t))
(defrule text (+ (not percent))
(:text t))
(defrule format (* (or field text)))
(defun expand-date-formatter-spec (spec)
"Expand a date spec like '%year %short-month %day %hour:%min'
to a list like '(:year :dhort-month :day :hour \":\" (:min 2))
note that:
- %% expands to \"%\"
- %min expands to (:min 2)
- %hour expands to (:hour 2)
- %day expands to (:day 2)
This list can be passed to misc:format-time to get a time string"
(let ((parsed (parse 'format spec)))
(loop for element in parsed collect
(cond
((string= element "%%")
"%")
((string= element "%min")
'(:min 2))
((string= element "%hour")
'(:hour 2))
((string= element "%day")
'(:day 2))
((scan "^%+" element)
(make-keyword (string-upcase (subseq element 1))))
(t
element)))))