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Topic: Machine Translation in C++

• 0:50 Introduction to Translation: Translation involves changing from one thing to another, including spoken languages and computer languages. The speaker discusses machine translation.

• 0:51:49 - The Machine and its Purpose: The talk focuses on a machine used to inspect wheel axles in trains for cracks, using non-destructive methods.

• 0:53:11 Company Origins (2009): The company was founded after a major train accident in Germany, with the goal of improving wheel axle inspections using automated machines.

• 0:54:31 Early Approach (Boost Format): Initially, the company used Boost Format for string concatenation, supporting only German.

• 0:55:52 Expanding Languages (Boost Local): As the company gained international customers, they needed to support other languages, starting with Czech. They explored Boost Local for handling string translations.

• 0:56:52 Translation System Criteria: The speaker talks about key criteria for their translation system: maturity, ecosystem (editors/build systems), code integration, and ease of use for non-expert end-users.

• 0:57:20 File Format Choice (Text Files): To accommodate non-technical users, they chose plain text files for translations, similar to Gettext library.

• 0:58:04 Gettext Library: The translation at runtime is done through the gex library. Front end consists of individual translations and the backend does the message cataloge loading.

• 1:00:05 Translation Workflow (Gettext Tools): The standard workflow using gex involves marking strings, scanning source files, creating .po files, translating with customer input, and generating .mo files for each language.

• 1:00:07 - Unicode and the Common Language Data Repository (CLDR): Discusses the role of Unicode in translation. Unicode's CLDR helps manage language-specific pluralization rules.

• 1:00:10 How Translation Works (CLDR): Unicode's Common Language Data Repository (CLDR) defines pluralization rules for different languages. These rules are expressed as single-line C expressions.

• 1:00:30 Limitations of Boost Local: Boost Local performs encoding conversions alongside translation, which is unnecessary for Unicode-only projects, causing unwanted string allocations.

• 1:09:17 - Transition to Fmt Format (2018): The company switched to Fmt Format for better performance and control. This involved using type lists and type erasure to avoid code bloat.

• 1:12:00 - Type-Based Metaprogramming: Talks about template calculating types. Employs partial template specialization to change inner workings of a library. However, can be costly and to avoid doing it unless neccessary.

• 1:14:15 - Functions and Meta Programming: Describes how functions can operate on values and types, a concept central to type-based metaprogramming.

• 1:17:35 - Impact of C++20 (P2216): C++20 and the adoption of P2216 changed the signature of format functions, requiring changes to translation approaches.

• 1:18:52 - Const Eval: Constant eval functions can only be computed at compilation time which improves code at run time.

• 1:25:57 - The Problem (Compile Time vs Run Time): With P2216 and consteval, parts of translation that previously could have been deferred to runtime were now constrained to compile time.

• 1:27:58 - Custom Overload (Solution to the Problem): To address the compile-time constraint, the presenter discusses the implementation of a custom overload to deal with the different language plurl forms.

• 1:30:00 Embracing Compile-Time Evaluation: The speaker asks if instead of storing strings, why can't the hashes be calculated so that the code only has to deal with numbers at the front end.

• 1:30:15 - Questions from Compiler Translation: The approach of generating the hashes leaves the code with three questions, which of the arguments is the right translation, how to get the value and if the arguments need to be translated.

• 1:33:00 Heterogeneous Sequences and Folds : Discusses use of pattern matching of C++ to find indexes in typelists at compile time. This improves translation at runtime. The best part is that this is valid C++ code, with no unefined behaviours.

• 1:34:15 - Implementation with C++17: Describes how fold expressions and C++17 features are used to find indices in type lists and extract values at compile time.

• 1:41:55 Testing at Compile Time: Code was written to extract strings as particular translations and to compile them into pOS which are merged into the MO and injected into the test function and then the testing occurs at compile time.

• 1:47:14 Run-Time Testing: You can then perform the same testing of MO files at run time.

• 1:48:44 GitHub Repository: Unfortunately the code is private.

• 1:50:03 Question 1 - Artefact Sent To Translating Company: Is the translation artefact, the scanned out pOS files that extract the strings from the build.

• 1:50:11 Question 2 - Floating Point Translations: Floating point translations aren't handled, as there's no interpretation for those types of translations, only individual strings are handled and translated.

• 1:50:21 Question 3 - C hash version?: There's a version of the C compiler that does that right now.

• **1:52:55 Questions regarding to language are about supporting a single quantity in translation.