Boston C++ June 2025 meetup

Execution based metaprogramming in C++ with BuildIt

TL;DR: Lots of C++ hacks to implement staged execution in C++; Hands-on examples; Free swag!

Metaprogramming an essential part of modern C++ is an amazing fit for balancing productivity and high-performance.

However even with modern C++ support for compile time execution, metaprogramming in C++ remains limited in features and wildly un-ergonomic to use.

In this presentation I will make a case for why explicit multi-stage execution (code-generating-code) is a better alternative and how it greatly improves productivity without sacrificing any performance.

We will dive deep into the implementation of BuildIt (https://buildit.so) and a bunch of never-seen-before tricks to implement code and type reflection in standard C++ 11.

We will also walk through some applications built with the system and other related tools that make the experience even better.

We have some free swag for attendees :)

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Ajay Brahmakshatriya is a 7th yeah PhD student in the Compilers@MIT (COMMIT) group advised by Prof. Saman Amarasinghe. Ajay’s research is focused on making it possible for non-compiler experts to design and implement their own DSLs. Ajay likes to build fast and easy to use abstractions for CPUs and GPUs.

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NOTE: Please make sure to arrive BEFORE 7PM as the doors close after that time.
Enter 32 Vassar St from the entrance closest to the intersection of Vassar St. and Main St. right behind the Sean Collier Memorial.
The door has ID scanners near the door, but should be open before 7 pm without access.
After getting inside keep walking till you see a right turn and you should see 3 elevators with “CSAIL” in big neon lights above it.
This is the G tower.
Go up any of the elevators to the 8th floor.
Once you enter the floor turn left and walk straight, you should reach 32-G882
If you happen to arrive AFTER 7PM the doors will be locked by you can still enter by following the steps below

• Use the event login (https://all.atlas-apps.mit.edu/TDvkcLvwBKDKEnsf8).
• This will require to install an app and should provide you with QR codes you can use to get through all the doors.