From 67f35806b89e6fa04d2779a88737ae2e88505a96 Mon Sep 17 00:00:00 2001
From: Jaidyn Ann <10477760+JadedCtrl@users.noreply.github.com>
Date: Mon, 5 Feb 2024 11:24:30 -0600
Subject: [PATCH] Init

---
 vcarded.scm | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 vcarded.scm

diff --git a/vcarded.scm b/vcarded.scm
new file mode 100644
index 0000000..13642c8
--- /dev/null
+++ b/vcarded.scm
@@ -0,0 +1,59 @@
+;; Copyright © 2024 Jaidyn Ann <jadedctrl@posteo.at>
+;;
+;; 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 <https://www.gnu.org/licenses/>.
+
+(import
+  scheme
+  (chicken io)
+  (chicken irregex)
+  (chicken string)
+  srfi-1)
+
+
+;; Splits a string into a list of CRLF’d lines.
+(define (lines string)
+  (remove string-null? (string-split string "\r\n")))
+
+
+;; Create irregx-format regex for matching an unescaped character.
+(define (regex-unescaped-char char-string)
+  `(: (neg-look-behind "\\") ,char-string))
+
+
+;; Splits a line into a list of key/value pairs.
+(define (split-vcard-line line)
+  (let ([split (irregex-split (regex-unescaped-char ":") line)])
+    (if (>= (length split) 2)
+        (cons
+         (car split)
+         (reduce-right (lambda (a b) (conc a ":" b)) "" (cdr split)))
+        #f)))
+
+
+;; Splits a key or value-element into its (potentially multiple) parameters.
+(define (split-vcard-element key-or-value)
+  (irregex-split (regex-unescaped-char ";") key-or-value))
+
+
+;; Parse a line of a vcard file into an alist-friendly format:
+;;    (KEY ("keyprop1=d" "keyprop2=b") "VALUE" ("valprop1=a" "valprop2=b"))
+(define (parse-vcard-line line)
+  (let* ([key-value-strings (split-vcard-line line)]
+         [key-elements (split-vcard-element (car key-value-strings))]
+         [value-elements (split-vcard-element (cdr key-value-strings))])
+    (list (string->symbol (car key-elements))
+          (cdr key-elements)
+          (car value-elements)
+          (cdr value-elements))))
+