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My favorite use is putting user-defined attributes on data members, and using reflection to generate a UI to manipulate those values. I do it with these shadert

My favorite use is putting user-defined attributes on data members, and using reflection to generate a UI to manipulate those values. I do it with these shadertoys: https://github.com/seanbaxter/shaders#reflection-and-attributes-for-shadertoy-development https://github.com/seanbaxter/shaders#reflection-and-attribu... Just mark your declarations up with custom attributes: [[.imgui::range_float { .1, 5 }]] float Zoom = 1.5; [[.imgui::range_float { 0, 1 }]] float Speed = .15; [[.imgui::range_float { .1, 1 }]] float XScale = .3; [[.imgui::range_float { 0, .5 }]] float YScale = .2; Then loop over the members with a meta for, and emit widget code that's guided by the attribute kind and data. These attributes each define a scrollbar. The kind of data you reflect over will likely come from within the program.

nikki93 5y ago
Nice! This is definitely my main usecase for reflecty things lately, along with serialization for the data (game engine scenarios). I've been doing static reflection + attributes through this: https://godbolt.org/z/enh8za4ja https://godbolt.org/z/enh8za4ja Which actually comes out to a not-so-bad syntax and the attributes can be read constexpr (some limitations though: simple aggregate-y structs, and all reflected fieds must appear before non-reflected ones). Lately I've been working on a Go (pretty small subset -- no GC or concurrency) to C++ compiler and generating meta stuff as part of it. Mostly because I like how focused Go's syntax is and also it having an official parser and type checker in the standard library makes things pretty quick to get started. I should play with Circle some time! It's definitely touching on a lot of the desired things from a metaprogramming layer.
jcelerier 5y ago
In c++ there are some hacks that can start to help getting someswhere close (https://ossia.io/posts/reflection/ https://ossia.io/posts/reflection/) but this solution with attributes is what everyone dreams of

nikki93 5y ago

Nice! This is definitely my main usecase for reflecty things lately, along with serialization for the data (game engine scenarios). I've been doing static reflection + attributes through this: https://godbolt.org/z/enh8za4ja https://godbolt.org/z/enh8za4ja Which actually comes out to a not-so-bad syntax and the attributes can be read constexpr (some limitations though: simple aggregate-y structs, and all reflected fieds must appear before non-reflected ones). Lately I've been working on a Go (pretty small subset -- no GC or concurrency) to C++ compiler and generating meta stuff as part of it. Mostly because I like how focused Go's syntax is and also it having an official parser and type checker in the standard library makes things pretty quick to get started. I should play with Circle some time! It's definitely touching on a lot of the desired things from a metaprogramming layer.

jcelerier 5y ago

In c++ there are some hacks that can start to help getting someswhere close (https://ossia.io/posts/reflection/ https://ossia.io/posts/reflection/) but this solution with attributes is what everyone dreams of