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March 15, 2010 [Issue 3967] New: bool opEquals() for structs instead of int opEquals() | ||||
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http://d.puremagic.com/issues/show_bug.cgi?id=3967 Summary: bool opEquals() for structs instead of int opEquals() Product: D Version: 2.041 Platform: All OS/Version: All Status: NEW Keywords: accepts-invalid Severity: normal Priority: P2 Component: DMD AssignedTo: nobody@puremagic.com ReportedBy: bearophile_hugs@eml.cc --- Comment #0 from bearophile_hugs@eml.cc 2010-03-15 10:23:12 PDT --- This page: http://www.digitalmars.com/d/2.0/operatoroverloading.html Contains: If structs declare an opEquals member function, it should follow the following form: struct S { int opEquals(ref const S s) { ... } } But opEquals of classes returns a boolean, so I think it's better for opEquals of structs too to return a boolean. I think you must be sure opEquals returns a bool. So the specs can be changed into something like: struct S { bool opEquals(ref const(S) s) { ... } } Currently this code runs: import std.c.stdio: printf; struct Foo { int data; int opEquals(T:Foo)(T other) { printf("A"); return this.data == other.data; } } void main() { int r = Foo(5) == Foo(5); } But I think dmd has to raise a c error, and require something like: bool opEquals(T:Foo)(ref const(Foo) other) { Or: bool opEquals(T:Foo)(const(Foo) other) { etc. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
March 18, 2010 [Issue 3967] bool opEquals() for structs instead of int opEquals() | ||||
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Posted in reply to bearophile_hugs@eml.cc | http://d.puremagic.com/issues/show_bug.cgi?id=3967 --- Comment #1 from bearophile_hugs@eml.cc 2010-03-18 14:30:25 PDT --- This shows why requiring a bool as return value of opEquals is necessary for generic code too (adapted from an idea of Bill Baxter): import std.c.stdio: printf; struct Foo { int x; int opEquals(T:Foo)(T other) { printf("****\n"); return this.x - other.x; } } bool bar(T)(T f1, T f2) { // return f1 == f2; // ERR return !!(f1 == f2); // OK, but silly } void main() { bool r = bar(Foo(1), Foo(2)); } -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
August 07, 2010 [Issue 3967] bool opEquals() for structs instead of int opEquals() | ||||
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Posted in reply to bearophile_hugs@eml.cc | http://d.puremagic.com/issues/show_bug.cgi?id=3967 Lutger <lutger.blijdestijn@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |lutger.blijdestijn@gmail.co | |m --- Comment #2 from Lutger <lutger.blijdestijn@gmail.com> 2010-08-07 03:13:55 PDT --- dmd (2.047) requires a signature of 'bool opEquals(ref const S s) const' and the same requirement is stated in TDPL. I assume that this is now just an issue of updating the spec, should this bug be closed and a new one filed? -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
August 07, 2010 [Issue 3967] bool opEquals() for structs instead of int opEquals() | ||||
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Posted in reply to bearophile_hugs@eml.cc | http://d.puremagic.com/issues/show_bug.cgi?id=3967 --- Comment #3 from bearophile_hugs@eml.cc 2010-08-07 03:20:00 PDT --- It's not a spec issue, this code compiles and runs with DMD 2.047 still: import std.c.stdio: printf; struct Foo { int data; int opEquals(T:Foo)(T other) { printf("A"); return this.data == other.data; } } void main() { int r = Foo(5) == Foo(5); } -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
August 07, 2010 [Issue 3967] bool opEquals() for structs instead of int opEquals() | ||||
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Posted in reply to bearophile_hugs@eml.cc | http://d.puremagic.com/issues/show_bug.cgi?id=3967 --- Comment #4 from Lutger <lutger.blijdestijn@gmail.com> 2010-08-07 04:42:33 PDT --- Something else is going on, the following does fail in line with your proposal: import std.c.stdio: printf; struct Foo { int data; int opEquals(ref const(Foo) other) const { printf("A"); return this.data == other.data; } } void main() { int r = Foo(5) == Foo(5); } output: Error: function test.Foo.opEquals type signature should be const bool(ref const(Foo)) not const int(ref const(Foo) other) Changing opEquals to return bool makes it compile correctly. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
December 11, 2011 [Issue 3967] TDPL bool opEquals() for structs instead of int opEquals() | ||||
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Posted in reply to bearophile_hugs@eml.cc | http://d.puremagic.com/issues/show_bug.cgi?id=3967 Andrei Alexandrescu <andrei@metalanguage.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED CC| |andrei@metalanguage.com Resolution| |FIXED --- Comment #5 from Andrei Alexandrescu <andrei@metalanguage.com> 2011-12-11 12:35:53 PST --- https://github.com/D-Programming-Language/d-programming-language.org/commit/086d56d031bbdbf5c96abd83ba51b7986bfcb2a9 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
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