C3 0.8.2 a Modest Improvement

# C3 0.8.2 A modest improvement Source: [https://c3-lang.org/blog/0_8_2_a_modest_improvement/](https://c3-lang.org/blog/0_8_2_a_modest_improvement/) [https://github.com/c3lang/c3-web/edit/main/docs/blog/posts/c3_0_8_2_a_modest_improvement.md](https://github.com/c3lang/c3-web/edit/main/docs/blog/posts/c3_0_8_2_a_modest_improvement.md)C3 0\.8\.2 is out\. This release brings a batch of language ergonomics improvements — most notably reusable target templates for libraries and generic constdef — along with new reflection capabilities and a round of bug fixes\. Compared to 0\.8\.1, this is a rather modest release, but anyway, here's what's new: ## Language changes & improvements[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#language-changes-improvements) ### Reusable target configurations for libraries[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#reusable-target-configurations-for-libraries) Libraries can now expose a templates map in their manifest, and projects can pull one into a target with template: "library/template"\. Template properties load first and target\-local settings override them, so libraries can ship sensible, shareable build configurations instead of asking every user to copy\-paste setup\. ### Reflection for generics[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#reflection-for-generics) `Foo::is\_generic\(\.\.\.\)`,`Foo::generic\_qname`, and`Foo::generic\_args`finally lets you inspect generic instantiations\. ``` alias Foo = List{int}; fn void main() { typeid t = List{String}::generic_args[0]; //String::typeid String name = Foo::generic_qname; // "std::collections::list::List" bool x = Foo::is_generic(List); // true bool y = int::is_generic(List); // false } ``` ### Bitstruct properties[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#bitstruct-properties) Bitstruct members gain`bitoffset`and`bitsize`properties: ``` bitstruct Foo : uint { uint a : 0..1; bool b : 6; bool c : 10; int d : 14..20; } fn void main() { int a = $reflect(Foo.a).bitsize; // 2 int b = $reflect(Foo.d).bitoffset; // 14 int c = $reflect(Foo.c).bitoffset; // 10 } ``` ### New @param options: own, init and drop[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#new-param-options-own-init-and-drop) It's now possible to annotate more than in/inout/out on parameters: 1. `own`signifies that the function will in some way retain the variable beyond the scope of the function\. 2. `drop`means that the pointer and the data pointed to will be invalid when the function returns\. 3. `init`means that the data pointed to will be initialized by the function\. This can be used by the compiler for static analysis and also documents the function or macro\. ``` <* @param [own] f *> fn void foo(Foo* f) { some_global.foo = f; } ``` ### Asm stack alignment[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#asm-stack-alignment) Before 0\.8\.2, all asm blocks would be stack aligned, which didn't match C behaviour\. This is now fixed\. Stack alignment is now opt\-in by using`@align`: ``` asm // Unaligned { syscall; } asm @align // Stack aligned { syscall; } ``` ### Windows improvements[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#windows-improvements) The Windows subsystem can now be set directly\. Windows can still use`@winmain`to implicitly set the Window subsystem, but all subsystems are now available, allowing for things like EFI applications\. ## Standard library[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#standard-library) - `Atomic\.compare\_exchange`added\. - `array::contains\_slice`and`array::index\_of\_slice`for substring\-style searches over arrays\. - `log::register\_dynamic\_category`, for libraries to define their own logging categories dynamically\. - `String\.index\_of`and`rindex\_of`now accept finding empty strings\. ## Fixes[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#fixes) ### Stdlib fixes[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#stdlib-fixes) - Denormal \(subnormal\) results are now handled correctly by`String\.to\_double\(\)`— very small magnitudes near the floating\-point floor previously came out wrong\. - A float literal with an uppercase F suffix was incorrectly typed as a double instead of a float\. - JSON serialization now correctly handles Unicode and \\v \(\#3353\)\. - IPv6 parsing: "a::b:c:d:e:f:0" is now accepted as valid\. - A regression in BackedArenaAllocator when destroying it could cause a crash\. - Fixed macOS regression which was breaking stack traces\. ### Compiler fixes[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#compiler-fixes) - `$stringify`would sometimes wrap output in extra parentheses\. - `constdef`vector with an alias was incorrectly lowered - The compiler asserted when concatenating a struct to an`untypedlist` - `untypedlist`was not detected as invalid as an enum associated\-value type or as a pointer ## Thank yous[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#thank-yous) Again, this release wouldn't have been possible without the C3 community\. I'd like to extend a deep thank you to all who have contributed, both through filed issues, PRs and just plain discussions\. ### PR contributors for this release[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#pr-contributors-for-this-release) **Stdlib:**AtomicSynth, Book\-reader, GuineaPigUuhh and Manu Linares **Compiler & toolchain:**Book\-reader, Johannes Müller, Manu Linares, Osama Badeeb, rickyadastra and Rodrigo Camacho **CI/Infrastructure:**Hade and Manu Linares ### Change Log[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#change-log) Click for full change log### Changes / improvements[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#changes-improvements) - `@weak`now works with all declarations\. - Add`@align`for asm blocks to stack align them\. Stack alignment is no longer default\. - Allow setting Windows subsystem directly\. - Add`bitoffset`and`bitsize`reflection properties to bitstruct members\. \#3219 - Improve error message on trying to cast char array to String\. \#3343 - Add`Foo::is\_generic\(\.\.\.\)`,`Foo::generic\_qname`and`Foo::generic\_args`\. \#2909 \#3329 - Add`own`,`init`and`drop`parameter annotations\. - `constdef`can now be generic\. - Libraries can now expose reusable target configurations via a`templates`map in their manifest, which projects reference from a target using`template: "library/template"`\. Properties from the template are loaded first and can be overridden by target\-local settings\. ### Stdlib changes[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#stdlib-changes) - `Atomic\.compare\_exchange`added\. - Added`array::contains\_slice`and`array::index\_of\_slice`\. - `String\.index\_of`and`rindex\_of`will now accept finding empty strings\. - Add log::register\_dynamic\_category, for libraries that wish to define their own categories dynamically\. ### Fixes[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#fixes_1) - `$stringify`would sometimes include parens\. - Regression when destroying a BackedArenaAllocator in some cases \#3332\. - `"a::b:c:d:e:f:0"`was not parsed as a valid ipv6 string\. - `constdef`vector with alias incorrectly lowered \#3335\. - Compiler asserts on concatenating a struct to an untypedlist \#3326\. - `untypedlist`was not detected as invalid in enum associated value type or as a pointer \#3342\. - Regression using non\-posix libc\. - Crash with an optional struct recursively defined with a function type\. \#3358 - Denormal results were not handled correctly by`String\.to\_double\(\)`\. - A float literal with an uppercase 'F' suffix would be a`double`instead of a`float`\. - Json serialization would not correctly handle unicode and`\\v`\. \#3353 - Semantic checking was incorrect in the case of`&a \- &b`where one or both are optional and the result isn't assigned\. - Regression on MacOS, breaking stack trace\. ### Want To Dive Into C3?[¶](https://c3-lang.org/blog/0_8_2_a_modest_improvement/#want-to-dive-into-c3) Check out the[documentation](https://c3-lang.org/getting-started/introduction/)or[download it and try it out](https://c3-lang.org/getting-started/prebuilt-binaries/)\. Have questions? Come and chat with us on[Discord](https://discord.gg/qN76R87)\.