\n\n#### Quick install\n```shell\nnpm install -g elchemy\n```\n\n# What is it?\nElchemy lets you write simple, fast and quality type safe code while leveraging both the Elm's safety and Elixir's ecosystem\n\n## [Test Elchemy online here](http://elchemy.neontree.pl) or here [Old (stable, no type checking) version](https://wende.github.io/elchemy/stable)\n## [Read Elchemy documentation here](https://wende.gitbooks.io/elchemy/content/)\n## [Read a tutorial on using Elchemy here](https://medium.com/@krzysztof.wende/elmchemy-write-type-safe-elixir-code-with-elms-syntax-part-1-introduction-8968b76d721d)\n## [Read our DevBlog on Medium here](https://medium.com/elchemy)\n## [Join Elchemy Slack Channel](https://join.slack.com/t/elchemy-lang/shared_invite/enQtNjE0NDQzNDE4NTM0LWQwMDNiYjBiOTg4YWE4NGE0MjQ2ZDkzZThiMGRkYjIyZjExMTA4MjQyMTc3ZTYzMDUyOGE3ZjVkNmI1YWMzYTQ)\n\n### In case of any questions about the project feel free to submit them in Issues with Q&A label\n\n# Features\n- **Type inference:** Powerful type inference means you rarely have to annotate types. Everything gets checked for you by the compiler\n- **Easy and type-safe interop**: You can call Elixir/Erlang without any extra boiler-plate. All the calls you make are checked in terms of type-safety as thoroughly as possible based on Elixir's typespecs.\n- **All the best of Elm and Elixir**: Elchemy inherits what's best in Elm - type safety, inference and extreme expressiveness, but also what's best in Elixir - Doc-tests, tooling and obviously the entire BEAM platform.\n- **Nearly no runtime errors** - Elchemy's type system **eliminates almost all runtime errors**. With a shrinking set of edge cases, your entire Elchemy codebase is safe. Elixir parts of the codebase are the only ones to be a suspect in cases of runtime errors happening.\n- **Beautiful and fully readable output** - The produced code is idiomatic, performant and can be easily read and analyzed without taking a single look at the original source.\n\n# Usage\n\n### Prerequisites\n- [elixir@1.4.0-1.6.x](https://elixir-lang.org/install.html)\n- [node@5+](https://nodejs.org/en/)\n- [elm-lang@0.18.0](https://guide.elm-lang.org/install.html) (`npm install -g elm@0.18.0`)\n- [elm-github-install@0.1.2](https://github.com/gdotdesign/elm-github-install) - Compiler will install it automatically for you, if you don't have it yet\n\n### Installation in Elixir project\nInstall `elchemy` globally with\n\n```shell\nnpm install -g elchemy\n```\n\nThen in root of your project do:\n```shell\nelchemy init\n```\n\nAnd follow the instructions\n\n`elchemy` will find all `*.elm` files specified in `elchemy_path` and compile it into corresponding `*.ex` files in `lib` directory.\n\nYou can override output directory specifying `elixirc_paths`.\n\n### Installation as a standalone\n```shell\nnpm install -g elchemy\n```\nUsage\n```\nelchemy compile source_dir output_dir\n```\n\n### Recommended editors setup\n- [Atom](https://atom.io/) with [elixir-language](https://atom.io/packages/language-elixir) and [atom-elixir](https://github.com/msaraiva/atom-elixir) or [elixir-ide](https://atom.io/packages/ide-elixir) for Elixir; and [language-elm](https://atom.io/packages/language-elm) + [elmjutsu](https://atom.io/packages/elmjutsu) for Elchemy.\n- [Visual Studio Code](https://code.visualstudio.com/) with [vscode-elixir](https://marketplace.visualstudio.com/items?itemName=mjmcloug.vscode-elixir), [vscode-elixir-ls](https://github.com/JakeBecker/vscode-elixir-ls) and [vscode-elm](https://github.com/Krzysztof-Cieslak/vscode-elm)\n\n### Build from source\n\n```\ngit clone https://github.com/wende/elchemy.git\ncd elchemy\nmake compile\n./elchemy compile source_dir output_dir\n```\nand \n```\nmake dev\n```\nTo launch and test the web demo\n\n# Contributing Guide\n- Everyone is welcome to contribute\n- Refer to http://bogdanp.github.io/elm-ast/example/ to have better understanding of parsed tokens.\n- Refer to https://wende.github.io/elchemy/stable/ to know the latest development version of the parser\n- For project management we use ZenHub. You can see the Kanban board, card estimates and all the reports by installing a browser extension here: [Opera/Chrome](https://chrome.google.com/webstore/detail/zenhub-for-github/ogcgkffhplmphkaahpmffcafajaocjbd), [Firefox](zenhub.com)\n\n## Targeted values:\n- Fully readable and indented elixir code generated from compilation\n- Seamless and stress less interop with existing Elixir code, preferably with magically working type safety\n- Full integration with entire elm syntax for editors and compilers magic\n\n## Troubleshooting\nIf something doesn't work, try \n```\nnpm install -g elchemy\nelchemy clean\nelchemy init\nmix test\n```\nfirst\n\n# FAQ\n## Why *would* I want to use that?\n- You like types\n- But even more you prefer compile-time errors over run-time error\n- You prefer `add b c = b + c` over `defp add(a, b), do: b + c`\n- You like curry\n- You think failing fast is cool, but not as cool as not failing at all\n\n## Why *wouldn't* I want to use that?\n- Your project relies on die-hard battle tested libraries, and you despise any versions starting with 0\n- You're afraid that when you learn what Monad is your mustache will grow, and eyesight weaken\n\n## Can I use it in already existing Elixir project?\nYou can, but nice and dandy compile tools are still on their way\n\n## Will my employer notice I'm having an affair with Elchemy?\nThe output files of Elchemy treat the code readability as a first class citizen. The code is meant to be properly indented, the comments aren't omitted, and the code is optimized as hard as it can ( f.i case clauses reduce to function overloads)\n\n## When will Elchemy become 1.0.0?\nWhen it's done\n\n## Can I contribute?\nDefinitely. Yes. Please do.\n\n## How are types represented?\nYou're a nosy one, aren't you?\nElchemy represents all type constructors as snake cased atoms, and all type applications as tuples.\nWhich means that `MyType 42 \"Forty two\" Error` in Elchemy equals to `{:my_type, 42, \"Forty Two\", :error}` in Elixir.\n\n## Can I use already existing Elm libraries with Elchemy?\nAs long as they don't use any Native modules, Ports or Elm runtime they can be safely imported and used\n\n## Can I use already existing Elixir libraries with Elchemy?\nYes. You can do an `ffi` call to any function in any module. Whether it's Elixir module, Erlang module, or even a macro you can include it in your code. Ffi calls are a treated specially in Elchemy, and they get generated test to analyze the types based on @specs, so that you don't compromise type safety for using Elixir code. \nIn order to increase readability it's advised not to use `ffi` calls if not necessary and always document and doctest them.\n\n## But what about out of function macros? Like tests and `use Module`?\nUnfortunately you can't write any macros with `do..end` blocks yet. You can write any out of function code using an elixir inline code with:\n```elm\n{- ex\n code_here\n-}\n```\nBut it's a last resort solution and shouldn't ever be abused.\n\n## Can I define an Elixir macro in Elchemy?\nSo you want to write an Elm-like code, that will manipulate Elixir code, which generates an Elixir code that manipulates Elixir code? How about no?\n\n## Do I need to have Elm installed to compile my `.elm` files with Elchemy?\nElchemy uses Elm to typecheck your program. It is possible to use it without Elm on your machine, while it's not advised.\n\n\n# Maturity of the project\n\n- Parser - **99%** of Elm's syntax (see [elm-ast](https://github.com/Bogdanp/elm-ast/issues))\n- Compiler - **90%** (Sophisticated incremental compilation. No support for Windows yet though ([#287](https://github.com/wende/elchemy/issues/287)) also big reliance on unix tools ([#288](https://github.com/wende/elchemy/issues/288))\n- Elchemy-core - **95%** ( Everything covered except side effects and JSON Decoders) \n- Interop with Elixir - **90%** - Purity tests ([#162](https://github.com/wende/elchemy/issues/162)) and handling of macro-heavy libraries ([#276](https://github.com/wende/elchemy/issues/276)) to go \n- Ideology - **70%** - We've got a pretty solid idea of where Elchemy is going \n- Documentation - **80%** - There are two tutorials and a complete Gitbook documentation. Few entrance level tutorials though\n- Elchemy-effects - **20%** - You can't and shouldn't write anything with side-effects in Elchemy yet. We're working on finding the best solution for effects that would fit both Elm's and Elixir's community (see [#297](https://github.com/wende/elchemy/issues/297) for more info)\n- Elchemy-core for Erlang VM - **5%** (Everything for os related tasks like filesystem, OTP goodies etc are yet to be done)\n\n# Contributor credits:\n\n- Tomasz Cichociński - [@baransu](https://github.com/baransu)\n- Colin Bankier - [@colinbankier](https://github.com/colinbankier)\n- Nathaniel Knight - [@neganp](https://github.com/neganp)\n","maintainers":[{"name":"wende","email":"chris@neontree.pl"}],"time":{"modified":"2022-06-16T09:02:03.794Z","created":"2017-05-03T12:23:19.904Z","0.0.21":"2017-05-03T12:23:19.904Z","0.0.22":"2017-05-03T12:24:46.769Z","0.0.31":"2017-05-10T22:17:08.933Z","0.0.32":"2017-05-10T22:22:59.596Z","0.0.33":"2017-05-10T22:24:50.560Z","0.0.34":"2017-05-10T22:26:46.149Z","0.0.35":"2017-05-11T11:01:27.311Z","0.0.36":"2017-05-11T11:02:56.693Z","0.0.37":"2017-05-11T14:47:23.173Z","0.0.38":"2017-05-11T15:46:46.557Z","0.0.39":"2017-05-11T15:48:00.075Z","0.0.40":"2017-05-11T15:58:49.331Z","0.0.41":"2017-05-11T16:25:48.287Z","0.0.42":"2017-05-11T16:28:31.871Z","0.0.43":"2017-05-11T16:34:34.647Z","0.0.44":"2017-05-11T16:36:41.493Z","0.0.45":"2017-05-11T16:37:41.441Z","0.0.46":"2017-05-11T16:51:02.571Z","0.0.47":"2017-05-11T16:53:37.060Z","0.0.48":"2017-05-11T16:56:34.949Z","0.0.49":"2017-05-11T16:59:07.265Z","0.0.50":"2017-05-11T17:07:19.314Z","0.0.51":"2017-05-11T17:26:22.753Z","0.0.52":"2017-05-11T17:41:34.648Z","0.0.53":"2017-05-11T17:57:00.069Z","0.0.54":"2017-05-11T18:00:30.219Z","0.1.0":"2017-05-11T18:02:38.817Z","0.2.0":"2017-05-15T21:16:52.749Z","0.2.1":"2017-05-16T09:36:34.916Z","0.2.2":"2017-05-16T21:30:23.151Z","0.3.0":"2017-05-28T23:36:21.744Z","0.3.1":"2017-05-29T21:04:30.894Z","0.3.2":"2017-05-29T21:05:57.789Z","0.3.3":"2017-05-29T21:08:18.959Z","0.3.4":"2017-05-29T21:34:47.022Z","0.3.5":"2017-05-29T21:39:15.507Z","0.3.6":"2017-05-29T22:14:19.713Z","0.3.7":"2017-05-29T22:19:21.501Z","0.3.8":"2017-05-31T17:01:33.527Z","0.3.9":"2017-05-31T23:11:48.939Z","0.3.10":"2017-06-04T19:15:29.790Z","0.3.11":"2017-06-07T19:36:55.307Z","0.3.12":"2017-06-07T22:03:21.184Z","0.3.13":"2017-06-07T22:08:10.417Z","0.3.14":"2017-06-08T13:43:26.313Z","0.3.15":"2017-06-08T13:51:03.724Z","0.3.16":"2017-06-08T15:11:57.056Z","0.3.17":"2017-06-08T18:35:52.519Z","0.3.18":"2017-06-08T18:42:26.921Z","0.3.19":"2017-06-08T18:47:17.552Z","0.3.20":"2017-06-08T19:18:29.169Z","0.3.21":"2017-06-08T19:23:52.036Z","0.3.22":"2017-06-08T19:26:06.500Z","0.3.23":"2017-06-08T20:20:19.503Z","0.3.24":"2017-06-08T20:22:35.780Z","0.3.25":"2017-06-09T19:53:47.414Z","0.3.26":"2017-06-09T21:07:19.633Z","0.3.27":"2017-06-09T22:29:10.307Z","0.3.28":"2017-06-10T16:44:09.966Z","0.3.29":"2017-06-13T19:35:52.366Z","0.3.30":"2017-06-13T20:44:00.392Z","0.3.31":"2017-06-13T21:29:16.856Z","0.3.32":"2017-06-28T14:18:56.718Z","0.3.33":"2017-07-01T00:58:04.165Z","0.3.34":"2017-07-07T18:16:21.764Z","0.4.0":"2017-07-07T18:16:44.976Z","0.4.1":"2017-07-07T18:26:43.037Z","0.4.3":"2017-07-07T18:36:50.460Z","0.4.4":"2017-07-07T18:38:06.386Z","0.4.5":"2017-07-07T18:48:31.180Z","0.4.6":"2017-07-14T17:33:55.503Z","0.4.7":"2017-07-14T18:06:32.733Z","0.4.9":"2017-07-14T18:45:16.739Z","0.4.10":"2017-07-14T20:24:15.586Z","0.4.11":"2017-07-17T23:25:03.933Z","0.4.12":"2017-08-05T03:42:34.796Z","0.4.13":"2017-08-12T12:59:31.342Z","0.4.14":"2017-08-19T11:56:45.577Z","0.4.15":"2017-08-20T09:01:45.254Z","0.4.16":"2017-08-20T09:08:05.810Z","0.4.17":"2017-08-20T09:12:31.368Z","0.4.18":"2017-08-20T09:13:42.939Z","0.4.20":"2017-08-20T09:18:55.168Z","0.4.21":"2017-08-20T09:23:25.345Z","0.4.22":"2017-08-20T09:25:42.909Z","0.4.24":"2017-08-20T09:32:57.226Z","0.4.25":"2017-08-20T09:36:18.210Z","0.4.26":"2017-08-20T09:39:24.530Z","0.4.27":"2017-08-20T09:48:32.930Z","0.4.28":"2017-08-20T09:56:31.281Z","0.4.29":"2017-08-20T09:57:32.394Z","0.4.30":"2017-08-20T10:02:32.745Z","0.4.31":"2017-08-20T13:53:06.290Z","0.4.32":"2017-08-20T21:54:38.420Z","0.4.33":"2017-08-24T10:23:28.851Z","0.4.34":"2017-08-24T16:05:28.197Z","0.4.35":"2017-09-05T15:14:25.185Z","0.4.36":"2017-09-05T15:25:48.322Z","0.4.37":"2017-09-06T14:04:24.902Z","0.4.38":"2017-09-06T17:08:27.921Z","0.4.39":"2017-09-07T10:18:30.148Z","0.4.40":"2017-09-09T23:54:11.676Z","0.4.41":"2017-09-15T10:55:12.519Z","0.4.42":"2017-09-16T19:16:47.265Z","0.4.43":"2017-09-16T19:18:00.453Z","0.4.44":"2017-09-16T19:55:53.910Z","0.4.45":"2017-09-16T19:58:16.313Z","0.4.46":"2017-10-01T23:51:42.010Z","0.4.47":"2017-10-01T23:57:05.283Z","0.4.48":"2017-10-02T00:01:38.517Z","0.4.49":"2017-10-02T00:04:47.012Z","0.4.50":"2017-10-02T00:20:18.358Z","0.4.51":"2017-10-20T12:34:03.473Z","0.4.52":"2017-10-29T14:48:14.077Z","0.4.53":"2017-10-29T14:53:11.145Z","0.4.54":"2017-10-29T15:31:01.407Z","0.4.55":"2017-10-29T15:44:25.693Z","0.5.0":"2017-10-29T15:49:12.262Z","0.5.1":"2017-11-08T13:59:08.418Z","0.5.2":"2017-11-26T03:25:52.280Z","0.5.3":"2017-11-27T16:03:44.789Z","0.5.5":"2018-01-21T14:40:20.510Z","0.5.6":"2018-01-28T01:09:53.318Z","0.6.0":"2018-01-30T16:55:55.452Z","0.6.1":"2018-01-30T17:00:49.103Z","0.6.2":"2018-01-30T18:47:54.210Z","0.6.3":"2018-01-30T20:14:12.154Z","0.6.4":"2018-02-06T23:06:03.457Z","0.6.6":"2018-03-05T15:04:31.488Z","0.7.0-0":"2018-05-11T17:22:45.957Z","0.7.0-2":"2018-05-11T19:54:45.817Z","0.7.0":"2018-05-14T10:49:20.608Z","0.7.1":"2018-05-15T14:58:44.011Z","0.7.2":"2018-05-16T20:38:49.118Z","0.7.3":"2018-05-23T12:08:18.078Z","0.7.4":"2018-05-24T10:11:42.567Z","0.8.0":"2018-09-22T18:40:43.468Z","0.8.4":"2019-04-01T19:37:15.108Z","0.8.5":"2019-04-01T20:00:39.921Z","0.8.7":"2019-04-01T21:35:20.704Z","0.8.8":"2019-05-02T19:26:17.388Z"},"homepage":"https://github.com/wende/elchemy#readme","repository":{"type":"git","url":"git+https://github.com/wende/elchemy.git"},"bugs":{"url":"https://github.com/wende/elchemy/issues"},"readmeFilename":"README.md"}
![](\"https://github.com/wende/elchemy/blob/master/logo.png?raw=true\"){kind=logo}
\n![](\"https://badges.gitter.im/elchemy-lang/Lobby.svg\")
\n ![](\"https://travis-ci.org/wende/elchemy.svg?branch=master\")
\n