The Crystal Programming Language
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Johannes Müller 6c38396bcb
Revert "Fix: cross-compile crashes when combined with emit llvm-bc or obj (#17060)" (#17080)
This reverts commit f38c6d949f.

It causes some yet unidentified codegen failure: #17077
2026-06-18 12:08:37 +02:00
.circleci Update previous Crystal release 1.20.2 (#16954) 2026-05-19 10:08:15 +02:00
.github [CI] Upgrade nixpkgs 26.05 in Lint workflow (#17066) 2026-06-12 11:59:02 +02:00
.well-known Fix funding.json well-known file name (#16000) 2025-07-18 22:43:35 +02:00
bin Apply shfmt (#17015) 2026-05-31 12:13:54 +02:00
doc Replace markdownlint with rumdl (#17069) 2026-06-14 12:24:10 +02:00
etc [CI] Upgrade library dependencies for Windows CI (#17025) 2026-06-03 21:38:34 +02:00
lib Apply mbake formatter for Makefile (#17024) 2026-05-31 15:40:21 +02:00
LICENSES Add REUSE.toml (#15992) 2025-07-24 11:46:31 +02:00
samples Apply mbake formatter for Makefile (#17024) 2026-05-31 15:40:21 +02:00
scripts Apply mbake formatter for Makefile (#17024) 2026-05-31 15:40:21 +02:00
spec Disable transport read-ahead for kTLS sockets (#17053) 2026-06-14 12:25:57 +02:00
src Revert "Fix: cross-compile crashes when combined with emit llvm-bc or obj (#17060)" (#17080) 2026-06-18 12:08:37 +02:00
.ameba.yml Add compiler-cli test suite (#17033) 2026-06-09 18:15:07 +02:00
.editorconfig Add trailing newlines (#15870) 2025-06-12 09:32:24 +02:00
.gitattributes Add devenv (#16263) 2025-10-26 19:26:57 +01:00
.gitignore Makefile: Build manpages for install target (#16991) 2026-05-23 14:42:06 +02:00
.mailmap Add git mailmap (#15396) 2025-02-12 13:21:54 +01:00
.markdownlint.yaml Replace markdownlint with rumdl (#17069) 2026-06-14 12:24:10 +02:00
.markdownlintignore Add .markdownlintignore (#16252) 2025-10-24 16:24:58 +02:00
.mbake.toml Apply mbake formatter for Makefile (#17024) 2026-05-31 15:40:21 +02:00
_typos.toml Rename parameter writeable to writable in IO::Memory.new (#16858) 2026-04-23 09:31:25 +02:00
Brewfile Bump Brewfile llvm@9 -> llvm@11 (#10340) 2021-02-19 18:51:47 -03:00
CHANGELOG.md Add changelogs for older releases (#16698) 2026-03-07 10:05:56 +01:00
CODE_OF_CONDUCT.md Fix markdownlint violations (#16222) 2025-10-20 12:45:34 +02:00
CONTRIBUTING.md Fix markdownlint violations (#16222) 2025-10-20 12:45:34 +02:00
devenv.lock Update devenv.lock (#17075) 2026-06-17 18:30:48 +02:00
devenv.nix Replace markdownlint with rumdl (#17069) 2026-06-14 12:24:10 +02:00
devenv.yaml infra: devenv input for git-hooks follows nixpkgs (#17064) 2026-06-12 11:02:11 +02:00
LICENSE Fix LICENSE and add NOTICE file (#3903) 2020-04-10 16:41:08 -03:00
Makefile Add compiler-cli test suite (#17033) 2026-06-09 18:15:07 +02:00
Makefile.win Add compiler-cli test suite (#17033) 2026-06-09 18:15:07 +02:00
NOTICE.md Update copyright year (#16550) 2026-01-04 13:46:33 +01:00
README.md Fix markdownlint violations (#16222) 2025-10-20 12:45:34 +02:00
REUSE.toml Update copyright year (#16550) 2026-01-04 13:46:33 +01:00
SECURITY.md Fix markdownlint violations (#16222) 2025-10-20 12:45:34 +02:00
shard.lock Add optional sanitizer to docs generator (#14646) 2025-10-22 11:46:34 +02:00
shard.yml Update previous Crystal release 1.20.0 (#16844) 2026-04-20 12:08:26 +02:00
shell.nix Update previous Crystal release 1.20.2 (#16954) 2026-05-19 10:08:15 +02:00
UPGRADING.md Add changelogs for older releases (#16698) 2026-03-07 10:05:56 +01:00

Crystal

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Crystal - Born and raised at Manas

Crystal is a programming language with the following goals:

  • Have a syntax similar to Ruby (but compatibility with it is not a goal)
  • Statically type-checked but without having to specify the type of variables or method arguments.
  • Be able to call C code by writing bindings to it in Crystal.
  • Have compile-time evaluation and generation of code, to avoid boilerplate code.
  • Compile to efficient native code.

Why?

We love Ruby's efficiency for writing code.

We love C's efficiency for running code.

We want the best of both worlds.

We want the compiler to understand what we mean without having to specify types everywhere.

We want full OOP.

Oh, and we don't want to write C code to make the code run faster.

Project Status

Within a major version, language features won't be removed or changed in any way that could prevent a Crystal program written with that version from compiling and working. The built-in standard library might be enriched, but it will always be done with backwards compatibility in mind.

Development of the Crystal language is possible thanks to the community's effort and the continued support of 84codes and every other sponsor.

Installing

Follow these installation instructions

Try it online

play.crystal-lang.org

Documentation

Community

Have any questions or suggestions? Ask on the Crystal Forum, on our Gitter channel or IRC channel #crystal-lang at irc.libera.chat, or on Stack Overflow under the crystal-lang tag. There is also an archived Google Group.

Contributing

The Crystal repository is hosted at crystal-lang/crystal on GitHub.

Read the general Contributing guide, and then:

  1. Fork it (https://github.com/crystal-lang/crystal/fork)
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request