digitalmars.D.bugs - [Issue 2701] New: Can't declare struct, assign lvalue to it in same statement
- d-bugmail puremagic.com (33/33) Mar 01 2009 http://d.puremagic.com/issues/show_bug.cgi?id=2701
- d-bugmail puremagic.com (12/12) Mar 01 2009 http://d.puremagic.com/issues/show_bug.cgi?id=2701
- d-bugmail puremagic.com (28/28) Aug 15 2010 http://d.puremagic.com/issues/show_bug.cgi?id=2701
http://d.puremagic.com/issues/show_bug.cgi?id=2701 Summary: Can't declare struct, assign lvalue to it in same statement Product: D Version: 2.025 Platform: PC OS/Version: Windows Status: NEW Keywords: rejects-valid, spec Severity: normal Priority: P2 Component: DMD AssignedTo: bugzilla digitalmars.com ReportedBy: dsimcha yahoo.com struct Bar { uint num; Bar opAssign(uint otherNum) { num = otherNum; return this; } } void main() { uint foo = 1; Bar bar = foo; // Error: e2ir: cannot cast from uint to Bar. Bar bar2; bar2 = foo; // Works. } Not sure if this is actually a valid bug, since the spec states that "The assignment operator cannot be overloaded for rvalues that can be implicitly cast to the lvalue type." However, if the previous sentence does implicitly disallow this from working, it should be stated more clearly, instead of in a single sentence of language legalese. --
Mar 01 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2701 ------- You can't use opAssign for initialisation; you have to use opCall. Specifically, Bar bar = foo; is rewritten as: Bar bar = Bar(foo); which is further rewritten as: Bar bar = Bar.opCall(foo); I'm not sure if this is documented explicitly anywhere; I just remember this from when it was implemented. --
Mar 01 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2701 David Simcha <dsimcha yahoo.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |INVALID I'm closing this, since this appears to be what C'tors are for. The following example demonstrates. Perhaps this should be better documented, though. struct Bar { uint num; this(uint otherNum) { opAssign(otherNum); } Bar opAssign(uint otherNum) { num = otherNum; return this; } } void main() { int foo = 1; Bar bar = foo; // Error: e2ir: cannot cast from uint to Bar. Bar bar2; bar2 = foo; // Works. } -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Aug 15 2010