The Power of C++ Templates With mp-units: Lessons Learned & a New Library Design

on YouTube ↗01h 23m

" summary

mp-units v2 rewrites the library: removes the problematic Downcasting Facility, abandons user-defined literals for quantities, and models ISO ISQ quantity trees so frequency, radioactivity and “one per second” stay distinct. It uses heavy C++20/23 NTTPs and expression templates to generate readable compiler types, supports quantity kinds for safe addition/conversion (preventing Hz+Bq), exposes value/reference as structural NTTPs, and requires modern compilers (GCC 12.2+) while adding features like compile‑time physical constants (g, c) that strip where possible.

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" chapters (15)

1. 0:00mp-units library rewrite intro
2. 1:46Previous design issues
3. 8:27Doncaster casting limits
4. 17:14User-defined literals drawbacks
5. 21:50mp-units v2 introduction
6. 25:23International System of Quantities
7. 31:01Quantity kinds importance
8. 39:38Quantity specs & units
9. 48:51Creating quantities in v2
10. 54:08Error messages with expression templates
11. 1:00:27Quantity conversions & casts
12. 1:08:59ADL limits with NTTPs
13. 1:14:09Affine types & quantity points
14. 1:16:12Lightweight physical constants
15. 1:19:45Improvements & future directions

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