digitalmars.D.bugs - [Issue 3876] New: std.range.Take back/popBack methods don't work correctly
- d-bugmail puremagic.com (131/131) Mar 04 2010 http://d.puremagic.com/issues/show_bug.cgi?id=3876
- d-bugmail puremagic.com (10/10) May 29 2010 http://d.puremagic.com/issues/show_bug.cgi?id=3876
- d-bugmail puremagic.com (11/11) May 29 2010 http://d.puremagic.com/issues/show_bug.cgi?id=3876
- d-bugmail puremagic.com (12/12) May 29 2010 http://d.puremagic.com/issues/show_bug.cgi?id=3876
- d-bugmail puremagic.com (11/11) Jun 13 2010 http://d.puremagic.com/issues/show_bug.cgi?id=3876
http://d.puremagic.com/issues/show_bug.cgi?id=3876 Summary: std.range.Take back/popBack methods don't work correctly Product: D Version: 2.040 Platform: All OS/Version: All Status: NEW Severity: normal Priority: P2 Component: Phobos AssignedTo: nobody puremagic.com ReportedBy: philippe.sigaud gmail.com 15:24:27 CET --- std.range.Take back and popBack methods do not work correctly: ---- import std.range; void main() { auto r = [0,1,2,3,4]; auto t = take(3,r); assert(equal(t, [0,1,2][])); // OK. assert(equal(retro(t), [4,3,2,1,1,0,0][])); // Something is wrong. } ---- Here is a version that seems to work, though the code may not be as clean as it should (and Take's code wasn't pretty to begin with...) It demands rather strict conditions on the input range: back/popBack need a random-access range with a length. ---- struct Take(R) if (isInputRange!(R)) { private: size_t _maxAvailable; R _input; enum bool byRef = is(typeof(&(R.init[0]))); public: alias R Source; static if (byRef) alias ref .ElementType!(R) ElementType; else alias .ElementType!(R) ElementType; bool empty() { return _maxAvailable == 0 || _input.empty; } void popFront() { enforce(_maxAvailable > 0); _input.popFront; --_maxAvailable; } // UGLY mixin( (byRef ? "ref " : "")~ q{ElementType front() { enforce(_maxAvailable > 0); return _input.front; }}); static if (isInfinite!(R)) { size_t length() const { return _maxAvailable; } void popBack() { enforce(_maxAvailable); --_maxAvailable; } } else static if (hasLength!(R)) { size_t length() { return min(_maxAvailable, _input.length); } static if (isRandomAccessRange!(R)) { void popBack() { if (_maxAvailable < _input.length) // changed from > to < { --_maxAvailable; } else { _input.popBack; } } } } static if (isRandomAccessRange!(R)) { mixin( (byRef ? "ref " : "")~ q{ElementType opIndex(uint index) { enforce(_maxAvailable > index); return _input[index]; } }); } /+ static if (isBidirectionalRange!(R)) { mixin( (byRef ? "ref " : "")~ q{ElementType back() { return _input[_maxAvailable]; } }); } else+/ static if (isRandomAccessRange!(R) /+&& isInfinite!(R)+/) { // Random access but not bidirectional could happen in the // case of e.g. some infinite ranges mixin( (byRef ? "ref " : "")~ q{ElementType back() { return _input[this.length() - 1]; } }); } Take opSlice() { return this; } } ---- -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Mar 04 2010
http://d.puremagic.com/issues/show_bug.cgi?id=3876 Shin Fujishiro <rsinfu gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |ASSIGNED CC| |rsinfu gmail.com AssignedTo|nobody puremagic.com |rsinfu gmail.com -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
May 29 2010
http://d.puremagic.com/issues/show_bug.cgi?id=3876 Shin Fujishiro <rsinfu gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution| |FIXED --- Fixed in svn r1566. Thanks for the code! It was very helpful. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
May 29 2010
http://d.puremagic.com/issues/show_bug.cgi?id=3876 Andrei Alexandrescu <andrei metalanguage.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|RESOLVED |REOPENED CC| |andrei metalanguage.com Resolution|FIXED | 06:59:09 PDT --- The constructor is now O(n), which is unacceptable. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
May 29 2010
http://d.puremagic.com/issues/show_bug.cgi?id=3876 Shin Fujishiro <rsinfu gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|REOPENED |RESOLVED Resolution| |FIXED --- The O(n) constructor was removed. Fixed in the release 2.047. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Jun 13 2010