scala 2.12.4 标准库源码

# Welcome! This is the official repository for the [Scala Programming Language](http://www.scala-lang.org). # How to contribute To contribute to the Scala standard library, Scala compiler, and Scala Language Specification, please send us a [pull request](https://help.github.com/articles/using-pull-requests/#fork--pull) from your fork of this repository. We do have to ask you to sign the [Scala CLA](http://www.lightbend.com/contribute/cla/scala) before we can merge any of your work into our code base, to protect its open source nature. For more information on building and developing the core of Scala, make sure to read the rest of this README! In order to get in touch with other Scala contributors, join [scala/contributors](https://gitter.im/scala/contributors) (Gitter) or post on [contributors.scala-lang.org](http://contributors.scala-lang.org) (Discourse). # Reporting issues Please report bugs at the [scala/bug issue tracker](https://github.com/scala/bug/issues). We use the [scala/scala-dev tracker](https://github.com/scala/scala-dev/issues) for coordinating bigger work items. # Get in touch! If you need some help with your PR at any time, please feel free to @-mention anyone from the list below, and we will do our best to help you out: | | username | talk to me about... | --------------------------------------------------------------------------------------------------|----------------------------------------------------------------|---------------------------------------------------| <img src="https://avatars.githubusercontent.com/adriaanm" height="50px" title="Adriaan Moors"/> | [`@adriaanm`](https://github.com/adriaanm) | type checker, pattern matcher, infrastructure, language spec | <img src="https://avatars.githubusercontent.com/SethTisue" height="50px" title="Seth Tisue"/> | [`@SethTisue`](https://github.com/SethTisue) | build, developer docs, community build, Jenkins, library, the welcome-to-Scala experience | <img src="https://avatars.githubusercontent.com/retronym" height="50px" title="Jason Zaugg"/> | [`@retronym`](https://github.com/retronym) | compiler performance, weird compiler bugs, Java 8 lambdas, REPL | <img src="https://avatars.githubusercontent.com/Ichoran" height="50px" title="Rex Kerr"/> | [`@Ichoran`](https://github.com/Ichoran) | collections library, performance | <img src="https://avatars.githubusercontent.com/lrytz" height="50px" title="Lukas Rytz"/> | [`@lrytz`](https://github.com/lrytz) | optimizer, named & default arguments | <img src="https://avatars.githubusercontent.com/VladUreche" height="50px" title="Vlad Ureche"/> | [`@VladUreche`](https://github.com/VladUreche) | specialization, Scaladoc tool | <img src="https://avatars.githubusercontent.com/densh" height="50px" title="Denys Shabalin"/> | [`@densh`](https://github.com/densh) | quasiquotes, parser, string interpolators, macros in standard library | <img src="https://avatars.githubusercontent.com/xeno-by" height="50px" title="Eugene Burmako"/> | [`@xeno-by`](https://github.com/xeno-by) | macros and reflection | <img src="https://avatars.githubusercontent.com/heathermiller" height="50px" title="Heather Miller"/> | [`@heathermiller`](https://github.com/heathermiller) | documentation | <img src="https://avatars.githubusercontent.com/dragos" height="50px" title="Iulian Dragos"/> | [`@dragos`](https://github.com/dragos) | specialization, back end | <img src="https://avatars.githubusercontent.com/axel22" height="50px" title="Aleksandr Prokopec"/> | [`@axel22`](https://github.com/axel22) | collections, concurrency, specialization | <img src="https://avatars.githubusercontent.com/janekdb" height="50px" title="Janek Bogucki"/> | [`@janekdb`](https://github.com/janekdb) | documentation | P.S.: If you have some spare time to help out around here, we would be delighted to add your name to this list! # Repository structure ``` scala/ +--build.sbt The main sbt build script +--lib/ Pre-compiled libraries for the build +--src/ All sources +---/library Scala Standard Library +---/reflect Scala Reflection +---/compiler Scala Compiler +---/eclipse Eclipse project files +---/intellij IntelliJ project templates +--spec/ The Scala language specification +--scripts/ Scripts for the CI jobs (including building releases) +--test/ The Scala test suite +---/files Partest tests +---/junit JUnit tests +--build/ [Generated] Build output directory ``` # Get ready to contribute ## Requirements You need the following tools: - Java SDK. The baseline version is 8 for both 2.12.x and 2.13.x. It may be possible to use a later SDK for local development, but the CI will verify against the baseline version. - sbt. We recommend the [sbt-extras](https://github.com/paulp/sbt-extras) runner script. It provides sensible default jvm options (stack and heap size). Mac OS X and Linux work. Windows may work if you use Cygwin. Community help with keeping the build working on Windows is appreciated. ## Tools we use We are grateful for the following OSS licenses: - [JProfiler Java profiler](https://www.ej-technologies.com/products/jprofiler/overview.html) - [YourKit Java Profiler](https://www.yourkit.com/java/profiler/) - [IntelliJ IDEA](https://www.jetbrains.com/idea/download/) ## Build setup ### Basics During ordinary development, a new Scala build is built by the previously released version. For short we call the previous release "starr": the stable reference Scala release. Building with starr is sufficient for most kinds of changes. However, a full build of Scala (a *bootstrap*, as performed by our CI) requires two layers. This guarantees that every Scala version can build itself. If you change the code generation part of the Scala compiler, your changes will only show up in the bytecode of the library and compiler after a bootstrap. See below for how to do a bootstrap build locally. For history on how the current scheme was arrived at, see https://groups.google.com/d/topic/scala-internals/gp5JsM1E0Fo/discussion. ### Using the sbt build Once you've started an `sbt` session you can run one of the core commands: - `compile` compiles all sub-projects (library, reflect, compiler, scaladoc, etc) - `scala` / `scalac` run the REPL / compiler directly from sbt (accept options / arguments) - `dist/mkBin` generates runner scripts (`scala`, `scalac`, etc) in `build/quick/bin` - `dist/mkPack` creates a build in the Scala distribution format in `build/pack` - `test` runs the JUnit test, `testOnly *immutable.ListTest` runs a subset - `partest` runs partest tests (accepts options, try `partest --help`) - `publishLocal` publishes a distribution locally (can be used as `scalaVersion` in other sbt projects) - Optionally `set baseVersionSuffix := "-bin-abcd123-SNAPSHOT"` where `abcd123` is the git hash of the revision being published. You can also use something custom like `"-bin-mypatch"`. This changes the version number from `2.12.2-SNAPSHOT` to something more stable (`2.12.2-bin-abcd123-SNAPSHOT`). - Note that the `-bin` string marks the version binary compatible. Using it in sbt will cause the `scalaBinaryVersion` to be `2.12`. If the version is not binary compatible, we recommen