Initial import

private/todo.rkt

@@ -0,0 +1,35 @@
+#lang racket/base
+
+(require racket/list
+         racket/string)
+
+(provide extract-todos)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Extract wiki todo(...) markers from Markdown source.
+; pre    : markdown is a string.
+; post   : Fenced code blocks are ignored and source is unchanged.
+; result : A list of hashes containing item number, line number and text.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (extract-todos markdown)
+  (define lines (string-split markdown "\n" #:trim? #f))
+  (define in-fence? #f)
+  (define item-number 0)
+  (define result '())
+  (for ((line (in-list lines))
+        (line-number (in-naturals 1)))
+    (define trimmed (string-trim line))
+    (cond
+      ((regexp-match? #px"^(```|~~~)" trimmed)
+       (set! in-fence? (not in-fence?)))
+      ((not in-fence?)
+       (for ((match (in-list (regexp-match* #px"todo\\([^()]+\\)" line))))
+         (define text (string-trim (substring match 5 (- (string-length match) 1))))
+         (when (not (string=? text ""))
+           (set! item-number (+ item-number 1))
+           (set! result
+                 (cons (hash 'number item-number
+                             'line line-number
+                             'text text)
+                       result)))))))
+  (reverse result))