0004079: Queue.copy is not tail recursive !

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Date Submitted

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0004079

OCaml

OCaml standard library

public

2006-08-07 15:58

2012-09-11 17:00

Reporter

Christophe

Assigned To

Priority

normal

Severity

minor

Reproducibility

always

Status

acknowledged

Resolution

open

Platform

OS Version

Product Version

3.09.2

Target Version

4.00.2+dev

Fixed in Version

Summary

0004079: Queue.copy is not tail recursive !

Description

Queue.copy is not tail recursive. Hence, large queue can not be safely duplicated.
This would be very simple to make it tail-recursive. I propose here a solution ;

let copy q =
  if q.length = 0 then
    create()
  else
    let tail = q.tail in

    let rec tail' = {
      content = tail.content;
      next = tail'
    } in

    let rec copy prev cell =
      if cell != tail
      then let res = {
        content = cell.content;
        next = tail'
      } in prev.next <- res;
      copy res cell.next in

    copy tail' tail.next;
    {
      length = q.length;
      tail = tail'
    }

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Issue History
Date Modified	Username	Field	Change
2006-08-07 15:58	Christophe	New Issue
2006-08-29 16:41	doligez	Status	new => acknowledged
2012-07-11 16:41	doligez	Target Version	=> 4.01.0+dev
2012-07-29 17:57	frisch	Category	OCaml general => OCaml standard library
2012-07-31 13:37	doligez	Target Version	4.01.0+dev => 4.00.1+dev
2012-09-11 17:00	doligez	Target Version	4.00.1+dev => 4.00.2+dev