On 04/19/2012 03:27 PM, Russel Winder wrote:
The program:import std.concurrency ; import std.stdio ; /*immutable*/ struct X { int i ; } void printI ( ) { receive ( ( X x ) { writeln ( x.i ) ; } ) ; } int main ( immutable string[] args ) { auto x = spawn (& printI ) ; x.send ( X ( 3 ) ) ; return 0 ; } behaves entirely as expected. Taking the comments off the immutable leads to: core.exception.AssertError@/home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/variant.d(286): X ---------------- /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(_d_assert_msg+0x1f) [0x43f81f] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(long std.variant.VariantN!(32uL).VariantN.handler!(immutableStruct.X).handler(std.variant.VariantN!(32uL).VariantN.OpID, ubyte[32]*, void*).bool tryPutting(immutableStruct.X*, TypeInfo, void*)+0x7a) [0x43b0fa] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(long std.variant.VariantN!(32uL).VariantN.handler!(immutableStruct.X).handler(std.variant.VariantN!(32uL).VariantN.OpID, ubyte[32]*, void*)+0x103) [0x43ae03] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(@property immutableStruct.X std.variant.VariantN!(32uL).VariantN.get!(immutableStruct.X).get()+0x57) [0x434cf7] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(void std.concurrency.Message.map!(void function(immutableStruct.X)*).map(void function(immutableStruct.X)*)+0x46) [0x434c96] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(bool std.concurrency.MessageBox.get!(void function(immutableStruct.X)*).get(scope void function(immutableStruct.X)*).bool onStandardMsg(ref std.concurrency.Message)+0x2d) [0x434731] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(bool std.concurrency.MessageBox.get!(void function(immutableStruct.X)*).get(scope void function(immutableStruct.X)*).bool scan(ref std.concurrency.List!(std.concurrency.Message).List)+0xd3) [0x434a47] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(bool std.concurrency.MessageBox.get!(void function(immutableStruct.X)*).get(scope void function(immutableStruct.X)*)+0x15e) [0x434692] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(void std.concurrency.receive!(void function(immutableStruct.X)*).receive(void function(immutableStruct.X)*)+0x2e) [0x434526] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(void immutableStruct.printI()+0x13) [0x433d1b] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(_D3std11concurrency11__T6_spawnZ6_spawnFbPFZvZS3std11concurrency3Tid4execMFZv+0x3d) [0x43abb5] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(void core.thread.Thread.run()+0x2a) [0x449caa] /tmp/.rdmd-1000/home/users/russel/Progs/OddsByLanguage/D/Odds/immutableStruct.d.EDDA68DBDAF917356C855298813D6CD2(thread_entryPoint+0xf3) [0x449a43] ---------------- I believe this is wrong on so many levels, but is it because I don't know D?
It certainly should work. std.concurrency does not do a good job dealing with head-immutable/head-const types currently (this includes class references). This needs to be fixed. The general problem is that it should be possible to declare a rebindable tail-immutable version of some type. std.typecons.Rebindable can be used for this, but an in-language solution would be superior.
