base/sequence.lisp

   1 ;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; indent-tabs-mode: nil -*-
   2 ;;;
   3 ;;; --- Sequence utils
   4 ;;;
   5
   6 (in-package :iolib.base)
   7
   8 (defmacro check-bounds (sequence start end)
   9   (with-gensyms (length)
  10     `(let ((,length (length ,sequence)))
  11        (check-type ,start unsigned-byte "a non-negative integer")
  12        (when ,end (check-type ,end unsigned-byte "a non-negative integer or NIL"))
  13        (unless ,end
  14          (setf ,end ,length))
  15        (unless (<= ,start ,end ,length)
  16          (error "Wrong sequence bounds. start: ~S end: ~S" ,start ,end)))))
  17
  18 (defun join (connector &rest strings)
  19   (let ((c (string connector)))
  20     (concatenate 'string (car strings)
  21                  (reduce (lambda (str1 str2)
  22                            (concatenate 'string str1 c str2))
  23                          (cdr strings)
  24                          :initial-value ""))))