Welcome to Swift!
Swift is a new, high performance systems programming language. It has a clean and modern syntax, and offers seamless access to existing C and Objective-C code and frameworks, and is memory safe (by default).
Although inspired by Objective-C and many other languages, Swift is not itself a C-derived language. As a complete and independent language, Swift packages core features like flow control, data structures, and functions, with high-level constructs like objects, protocols, closures, and generics. Swift embraces modules, eliminating the need for headers and the code duplication they entail.
To read the documentation, start by installing the Sphinx documentation
generator tool (http://sphinx-doc.org, just run easy_install -U Sphinx from
the command line and you're good to go). Once you have that, you can build the
swift documentation by going into swift/docs and typing make. This compiles
the 'rst' files in the docs directory into HTML in the swift/docs/_build/html
directory.
Once built, the best place to start is with the swift whitepaper, which gives a
tour of the language (in swift/docs/_build/html/whitepaper/index.html).
Another potentially useful document is docs/LangRef, which gives a low level
tour of how the language works from the implementation perspective.
Many of the docs are out of date, but you can see some historical design
documents in the docs directory.
Another source of documentation is the standard library itself, located at
swift/stdlib. Much of the language is actually implemented in the library
(including Int), and the standard library gives some examples of what can be
expressed today.
These instructions give the most direct path to a working Swift development environment. Options for doing things differently are discussed below.
OS X, Ubuntu Linux LTS, and the latest Ubuntu Linux release are the current supported host development operating systems.
CMake is used to build Swift and its companion projects; at least version 2.8.12.2 is required.
For OS X, you need the latest Xcode.
For Ubuntu, you'll need the following development dependencies:
sudo apt-get install git cmake ninja clang uuid-dev libicu-dev libbsd-dev libedit-dev swig libpython-dev libncurses5-dev
Note: LLDB currently requires at least swig-1.3.40 but will successfully build with version 2 shipped with Ubuntu.
git clone [email protected]:/apple/swift.git swift
git clone [email protected]:/apple/swift-llvm.git llvm
git clone [email protected]:/apple/swift-clang.git clang
git clone [email protected]:/apple/swift-lldb.git lldb
git clone [email protected]:/apple/swift-cmark.git cmark
git clone [email protected]:/apple/swift-llbuild.git llbuild
git clone [email protected]:/apple/swift-package-manager.git swiftpm
swift/utils/build-script -t
Note: Arguments after "--" above are forwarded build-script-impl, which is invoked by build-script. Ninja, is the current recommended cross-platform build system for building Swift. It's the default if you have it installed or have it checked out next to the swift directory.
swift/utils/build-script -m -t -- --build-args=-j8
The build-script has lots of useful options, including the ability to build an
LLDB that's compatible with the Swift in your working copy. To find out more:
swift/utils/build-script -h
To get verbose output, pass --build-args="VERBOSE=1"
The Xcode IDE can be used to edit the Swift source code, but it is not currently
fully supported as a build environment for SDKs other than OS X. If you'd like
to build for other SDKs but still use Xcode, once you've built Swift using Ninja
or one of the other supported CMake generators, you can set up an IDE-only Xcode
environment using the build-script's -X flag:
swift/utils/build-script -X --skip-build -- --reconfigure
The --skip-build flag tells build-script to only generate the project,
not build it in its entirety. A bare minimum of LLVM tools will build in order
to configure the Xcode projects.
The --reconfigure flag tells build-script-impl to run the CMake configuration
step even if there is a cached configuration. As you develop in Xcode, you may
need to rerun this from time to time to refresh your generated Xcode project,
picking up new targets, file removals, or file additions.
See docs/Testing.rst.