From 41fecf53f49b7a1c63b5e66f9d244bb75e564875 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20H=C3=B6rnquist?= <hugo@lysator.liu.se>
Date: Sat, 9 May 2020 02:54:38 +0200
Subject: Add draft of new parser.

---
 module/vcomponent/parse/new.scm | 91 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 module/vcomponent/parse/new.scm

(limited to 'module/vcomponent/parse')

diff --git a/module/vcomponent/parse/new.scm b/module/vcomponent/parse/new.scm
new file mode 100644
index 00000000..46660a9f
--- /dev/null
+++ b/module/vcomponent/parse/new.scm
@@ -0,0 +1,91 @@
+(define-module (vcomponent parse new)
+  :use-module (util)
+  :use-module ((ice-9 rdelim) :select (read-line))
+  :use-module (vcomponent base)
+ )
+
+
+;; (define f (open-input-file (car (glob "~/.local/var/cal/Calendar/c17*"))))
+;; (parse (map tokenize (read-file file)))
+
+;; port → (list string)
+(define (read-file port)
+ (let loop ((done '()))
+   (let ((line (read-line port)))
+     (if (eof-object? line)
+         (reverse! done)
+         (loop
+          (if (char=? #\space (string-ref line 0))
+              (cons (string-append (car done)
+                                   (string-drop line 1))
+                    (cdr done))
+              (cons line done)))))))
+
+;; (list string) → (list (key kv ... value))
+(define (tokenize line)
+  (define colon-idx (string-index line #\:))
+  (define semi-idxs
+    (let loop ((idx 0))
+      (aif (string-index line #\; idx colon-idx)
+           (cons it (loop (1+ it)))
+           (list colon-idx (string-length line)))))
+  (map (lambda (start end)
+         (substring line (1+ start) end))
+       (cons -1 semi-idxs)
+       semi-idxs))
+
+
+;; (parse-itemline '("DTEND" "TZID=Europe/Stockholm" "VALUE=DATE-TIME" "20200407T130000"))
+;; ⇒ #<<vline> value: "20200407T130000" parameters: #<hash-table 7f4294c913a0 2/31>>
+(define (parse-itemline itemline)
+  (define all
+    (reverse
+     (let loop ((rem (cdr itemline)))
+       (if (null? (cdr rem))
+           rem                             ; (list (car rem))
+           (let* ((kv (car rem))
+                  (idx (string-index kv #\=)))
+             (cons (cons (string->symbol (substring kv 0 idx))
+                         ;; NOTE handle value parsing here?
+                         (substring kv (1+ idx)))
+                   (loop (cdr rem))))))))
+
+  (make-vline% (car all) (alist->hashq-table (cdr all))))
+
+
+
+(use-modules (srfi srfi-9))
+(define-record-type <component>
+  (make-component% type children attributes parent)
+  component?
+  (type type)
+  (children children)
+  (attributes attributes))
+
+(define (make-component args)
+  (let* ((type (car args))
+         (children attributes (partition component? (cdr args))))
+    (make-component% type children attributes)))
+
+;; (list (key kv ... value)) → <vcomponent>
+(define (parse lst)
+  (let loop ((lst lst)
+             (stack '()))
+    (if (null? lst)
+        stack
+        (let ((head (car lst)))
+          (cond [(string=? "BEGIN" (car head))
+                 (loop (cdr lst) (cons (list (string->symbol (cadr head))) stack))]
+                [(string=? "END" (car head))
+                 (loop (cdr lst)
+                       (let* ((frame (reverse (car stack)))
+                              (component (make-component frame)))
+                         (if (null? (cdr stack))
+                             component
+                             (cons (cons component (cadr stack))
+                                   (cddr stack)))))]
+                [else
+                 (loop (cdr lst)
+                       (cons (cons (parse-itemline head)
+                                   (car stack))
+                             (cdr stack)))])))))
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