diff options
| -rw-r--r-- | ccwl/utils.scm | 9 | ||||
| -rw-r--r-- | tests/utils.scm | 6 |
2 files changed, 12 insertions, 3 deletions
diff --git a/ccwl/utils.scm b/ccwl/utils.scm index 508e884..d9d1ee3 100644 --- a/ccwl/utils.scm +++ b/ccwl/utils.scm @@ -1,5 +1,5 @@ ;;; ccwl --- Concise Common Workflow Language -;;; Copyright © 2021, 2022 Arun Isaac <arunisaac@systemreboot.net> +;;; Copyright © 2021, 2022, 2023 Arun Isaac <arunisaac@systemreboot.net> ;;; ;;; This file is part of ccwl. ;;; @@ -48,12 +48,17 @@ (display (make-string (* 2 level) #\space) port)) (define (pairify lst) - "Return a list of pairs of successive elements of LST. For example, + "Return a list of pairs of successive elements of LST. Ignore extra +elements when LST has an odd number of elements. For example, (pairify (list 1 2 3 4 5 6)) +=> ((1 . 2) (3 . 4) (5 . 6)) + +(pairify (list 1 2 3 4 5 6 7)) => ((1 . 2) (3 . 4) (5 . 6))" (match lst (() '()) + ((single-element) '()) ((first second tail ...) (cons (cons first second) (pairify tail))))) diff --git a/tests/utils.scm b/tests/utils.scm index b630b10..66220cc 100644 --- a/tests/utils.scm +++ b/tests/utils.scm @@ -1,5 +1,5 @@ ;;; ccwl --- Concise Common Workflow Language -;;; Copyright © 2021, 2022 Arun Isaac <arunisaac@systemreboot.net> +;;; Copyright © 2021, 2022, 2023 Arun Isaac <arunisaac@systemreboot.net> ;;; ;;; This file is part of ccwl. ;;; @@ -216,4 +216,8 @@ 0 0))) (list sum sum-of-squares))) +(test-equal "pairify must ignore extra elements when list has an odd number of elements" + '((1 . 2) (3 . 4) (5 . 6)) + (pairify (list 1 2 3 4 5 6 7))) + (test-end "utils") |