avoid a list operation

hyphenate/hyphenate/private/core.rkt

@@ -12,19 +12,29 @@
 (define default-joiner #\u00AD)
 
 
+(define (trim-points points)
+  ;; for point list generated from a pattern,
+  ;; drop first two elements because they represent hyphenation weight
+  ;; before the starting "." and between "." and the first letter.
+  ;; drop last element because it represents hyphen after last "."
+  ;; after you drop these two, then each number corresponds to
+  ;; whether a hyphen goes after that letter.
+  (drop-right (drop points 2) 1))
+
+
 ;; Convert the hyphenated pattern into a point array for use later.
 (define (convert-exception-word exception)
   (define (make-key x) (format ".~a." (string-replace x "-" "")))
   (define (make-value x)
     (append (list 0) (map (λ(x) (if (equal? x "-") 1 0)) (regexp-split #px"\\p{L}" x)) (list 0)))
   ;; use list instead of cons because value is itself a list, and consing will muddy the waters
-  (list (make-key exception) (make-value exception)))
+  (list (make-key exception) (trim-points (make-value exception))))
 
 
 (module+ test
-  (check-equal? (convert-exception-word "snôw-man") '(".snôwman." (0 0 0 0 0 1 0 0 0 0)))
-  (check-equal? (convert-exception-word "snôwman") '(".snôwman." (0 0 0 0 0 0 0 0 0 0)))
-  (check-equal? (convert-exception-word "sn-ôw-ma-n") '(".snôwman." (0 0 0 1 0 1 0 1 0 0))))
+  (check-equal? (convert-exception-word "snôw-man") '(".snôwman." (0 0 0 1 0 0 0)))
+  (check-equal? (convert-exception-word "snôwman") '(".snôwman." (0 0 0 0 0 0 0)))
+  (check-equal? (convert-exception-word "sn-ôw-ma-n") '(".snôwman." (0 1 0 1 0 1 0))))
 
 
 (define (add-exception-word word)
@@ -90,7 +100,6 @@
 
 (define (make-points word)
   (define word-with-dots (format ".~a." (string-downcase word)))
-  (define max-pattern
   (hash-ref! (current-word-cache) word-with-dots 
              (λ () ; compute pattern when missing from cache
                (define word-length (string-length word-with-dots))
@@ -107,15 +116,7 @@
                             (define left-zeroes (make-list start 0))
                             (define right-zeroes (make-list (- (add1 word-length) (length partial-pattern) start) 0))
                             (append left-zeroes partial-pattern right-zeroes)))
-                 (calculate-max-pattern (cons default-zero-pattern matching-patterns)))))
-  
-  ;; for point list,
-  ;; drop first two elements because they represent hyphenation weight
-  ;; before the starting "." and between "." and the first letter.
-  ;; drop last element because it represents hyphen after last "."
-  ;; after you drop these two, then each number corresponds to
-  ;; whether a hyphen goes after that letter.
-  (drop-right (drop max-pattern 2) 1))
+               (trim-points (calculate-max-pattern (cons default-zero-pattern matching-patterns))))))
 
 
 ;; Find hyphenation points in a word. This is not quite synonymous with syllables.