ledford@berlin.rtp.dg.com (10/20/89)
I have a question about the make-array function in Common Lisp as defined in "Common Lisp the Language" by Guy L. Steele Jr. If a non-nil fill-pointer is specified along with an initial-contents value, can only the active part of the array be initialized or do both the active and inactive parts have to be initialized. I can't find where Steele addresses this situation. Thanks in advance, Bruce Ledford, Data General Corp. 62 T.W. Alexander Drive Research Triangle Park, NC 27709 Internet: ledford@dg-rtp.DG.COM
barmar@kulla (Barry Margolin) (10/21/89)
In article <2013@xyzzy.UUCP> ledford@berlin.rtp.dg.com () writes: >I have a question about the make-array function in Common Lisp as >defined in "Common Lisp the Language" by Guy L. Steele Jr. If a >non-nil fill-pointer is specified along with an initial-contents >value, can only the active part of the array be initialized or >do both the active and inactive parts have to be initialized. >I can't find where Steele addresses this situation. The fill pointer is only used by functions that the documentation specifically says use it. Since the MAKE-ARRAY documentation doesn't say anything about only the active portion being initialized, it must be the entire thing. In general, the fill pointer is only used by sequence and string functions; the fill pointer exists primarily to allow vectors to be used to implement growable sequences with performance comparable to that of lists. Most functions that operate on arrays of any rank ignore the fill pointer. Barry Margolin, Thinking Machines Corp. barmar@think.com {uunet,harvard}!think!barmar