1 files changed, 43 insertions, 0 deletions
diff --git a/spellcheck/mutate.scm b/spellcheck/mutate.scm
new file mode 100644
index 0000000..117d0b3
--- /dev/null
+++ b/spellcheck/mutate.scm
@@ -0,0 +1,43 @@
+(define-module (mutate)
+  #:use-module (srfi srfi-1)
+  #:export (deletes
+            transposes
+            replaces
+            inserts))
+
+
+;; see https://norvig.com/spell-correct.html
+;; this is a translation of that from python
+;; to guile
+(define (deletes word)
+  (define (deletes-helper word splits result)
+    (if (null? splits)
+	result
+	(let* ((split (car splits))
+	       (tail (cdr split)))
+	  (if (zero? (string-length tail))
+	      (deletes-helper word (cdr splits) result)
+	      (deletes-helper word (cdr splits)
+			      (append result
+				      (list (string-append (car split) (substring tail 1)))))))))
+  (deletes-helper word (splits word) '()))
+
+(define (transposes word)
+  #t)
+
+(define (replaces word)
+  #t)
+
+(define (inserts word)
+  #t)
+
+
+(define (splits word)
+  "Given WORD, returns a list of pairs of
+all possible splits:
+
+'six' ->
+(('' . 'six') ('s' . 'ix') ('si' . 'x') ('six' . ''))"
+  (map (lambda (s) (cons (substring word 0 s)
+			 (substring word s)))
+       (iota (1+ (string-length word)))))