;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10 -*-
;;;; *************************************************************************
;;;; FILE IDENTIFICATION
;;;;
;;;; Name:          seqs.lisp
;;;; Purpose:       Sequence functions for KMRCL package
;;;; Programmer:    Kevin M. Rosenberg
;;;; Date Started:  Apr 2000
;;;;
;;;; $Id: seqs.lisp,v 1.3 2003/05/04 15:09:59 kevin Exp $
;;;;
;;;; This file, part of KMRCL, is Copyright (c) 2002 by Kevin M. Rosenberg
;;;;
;;;; KMRCL users are granted the rights to distribute and use this software
;;;; as governed by the terms of the Lisp Lesser GNU Public License
;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
;;;; *************************************************************************

(in-package :kmrcl)


(defun mapappend (func seq)
  (apply #'append (mapcar func seq)))

(defun mapcar-append-string-nontailrec (func v)
  "Concatenate results of mapcar lambda calls"  
  (aif (car v)
       (concatenate 'string (funcall func it)
		    (mapcar-append-string-nontailrec func (cdr v)))
       ""))


(defun mapcar-append-string (func v &optional (accum ""))
  "Concatenate results of mapcar lambda calls"  
  (aif (car v)
       (mapcar-append-string 
	func 
	(cdr v) 
	(concatenate 'string accum (funcall func it)))
       accum))

(defun mapcar2-append-string-nontailrec (func la lb)
  "Concatenate results of mapcar lambda call's over two lists"  
  (let ((a (car la))
	(b (car lb)))
    (if (and a b)
      (concatenate 'string (funcall func a b)
		   (mapcar2-append-string-nontailrec func (cdr la) (cdr lb)))
      "")))
  
(defun mapcar2-append-string (func la lb &optional (accum ""))
  "Concatenate results of mapcar lambda call's over two lists"  
  (let ((a (car la))
	(b (car lb)))
    (if (and a b)
	(mapcar2-append-string 
	 func 
	 (cdr la) 
	 (cdr lb)
	 (concatenate 'string accum (funcall func a b)))
      accum)))


(defun nsubseq (sequence start &optional end)
  "Return a subsequence by pointing to location in original sequence"
  (unless end (setq end (length sequence)))
  (make-array (- end start)
	      :element-type (array-element-type sequence)
	      :displaced-to sequence
	      :displaced-index-offset start))