digitalmars.dip.ideas - Runtime struct introspection
- monkyyy (58/58) May 26 Rikki suggest it was possible to write a templateless writeln for
- Stefan Koch (14/33) May 29 Wow ... I was unaware TypeInfo_Struct did not have members.
- monkyyy (6/47) May 29 Indifferent Im just expecting it to be dumped into memory and soa
Rikki suggest it was possible to write a templateless writeln for *that* pipe dream. But when I tried my hand at it; no, when I pull on typeinfo I can find all the details of the ast; but when you come to structs, its private and designed for the gc. https://github.com/dlang/dmd/blob/dbf2e20cdf7f8187920f7b357856d9b4f65c8d5e/druntime/src/object.d#L1941 ``` // The xopEquals and xopCmp members are function pointers to member // functions, which is not guaranteed to share the same ABI, as it is not // known whether the `this` parameter is the first or second argument. // This wrapper is to convert it to a delegate which will always pass the // `this` parameter in the correct way. private struct _memberFunc { union ``` I could probably reverse engineer to get the offsets but I dont really want to --- If walter wants *any* templateless write to work without disgusting format strings, you will need at least the layout, and typeinfo; if you want the format string to be programmable at all, youll need the names. ```d struct vector2{ int x; int y; ``` `vector2(3,5).runtimeprint;// "vector2(3,5)"` `vector2(3,5).runtimeprint("($.x,$.y)");// "(3,5)"` `vector2(3,5).runtimeprint("(x:$.x,y:$.y)");// "(x:3,y:5)"` --- So we do the song and dance, find the `object.TypeInfo_Struct` for vector2 I suggest the following functions is the minimum nessery for templateless printing: ``` TypeInfo_Struct t=typeid(vector2); assert(t.fields==["x","y"]); assert(t.fieldoffset==[0,int.sizeof]); assert(t.fieldtype==[typeid(int),typeid(int)]); ``` --- While your in there adding changing the abi I would suggest adding the following: ``` enum specialstructs = {none, nullable, sumtype, range} specialstructs magicnumber; //set by a pragma so theres at least an option of attempting to gracefully handle complex types int delegate(int delegate(void*))* __opApply; //generated if a foreachable opApply is defined, otherwise null bool function(void*)* truthy; //generated if cast(bool) or `bool empty` is defined, otherwise null ```
May 26
On Tuesday, 26 May 2026 at 14:56:50 UTC, monkyyy wrote:Rikki suggest it was possible to write a templateless writeln for *that* pipe dream. ... [] So we do the song and dance, find the `object.TypeInfo_Struct` for vector2 I suggest the following functions is the minimum nessery for templateless printing: ``` TypeInfo_Struct t=typeid(vector2); assert(t.fields==["x","y"]); assert(t.fieldoffset==[0,int.sizeof]); assert(t.fieldtype==[typeid(int),typeid(int)]); ``` ---On Tuesday, 26 May 2026 at 14:56:50 UTC, monkyyy wrote:Rikki suggest it was possible to write a templateless writeln for *that* pipe dream. But when I tried my hand at it; no, when I pull on typeinfo I can find all the details of the ast; but when you come to structs, its private and designed for the gc. https://github.com/dlang/dmd/blob/dbf2e20cdf7f8187920f7b357856d9b4f65c8d5e/druntime/src/object.d#L1941Wow ... I was unaware TypeInfo_Struct did not have members. what do you think about ``` struct TypeInfo_Member { TypeInfo tInfo; string name; size_t offset; } ``` and for `TypeInfo_Class` and `TypeInfo_Struct` as well as `TypeInfo_Enum` to have a `TypeInfo_Member[] members`;
May 29
monkyyy <crazymonkyyy gmail.com> On Friday, 29 May 2026 at 14:47:59 UTC, Stefan Koch wrote:On Tuesday, 26 May 2026 at 14:56:50 UTC, monkyyy wrote:Indifferent Im just expecting it to be dumped into memory and soa will be less lines of code and smaller, and maybe semi-compiletime string are complex somehow Traits are far from consistent but you do just need ways to grab data.Rikki suggest it was possible to write a templateless writeln for *that* pipe dream. ... [] So we do the song and dance, find the `object.TypeInfo_Struct` for vector2 I suggest the following functions is the minimum nessery for templateless printing: ``` TypeInfo_Struct t=typeid(vector2); assert(t.fields==["x","y"]); assert(t.fieldoffset==[0,int.sizeof]); assert(t.fieldtype==[typeid(int),typeid(int)]); ``` ---On Tuesday, 26 May 2026 at 14:56:50 UTC, monkyyy wrote:Rikki suggest it was possible to write a templateless writeln for *that* pipe dream. But when I tried my hand at it; no, when I pull on typeinfo I can find all the details of the ast; but when you come to structs, its private and designed for the gc. https://github.com/dlang/dmd/blob/dbf2e20cdf7f8187920f7b357856d9b4f65c8d5e/druntime/src/object.d#L1941Wow ... I was unaware TypeInfo_Struct did not have members. what do you think about ``` struct TypeInfo_Member { TypeInfo tInfo; string name; size_t offset; } ``` and for `TypeInfo_Class` and `TypeInfo_Struct` as well as `TypeInfo_Enum` to have a `TypeInfo_Member[] members`;
May 29