From ArchWiki

Running swift-language builds and doing swift development is possible on linux. To install swift use swift-binAUR for the released version, repackaged Fedora binary, or swift-languageAUR for a native build from source. swift-language-gitAUR will give the latest from git. For code completion the sourcekit language server protocol, sourcekit-lsp is available, e.g. as plugin to visual studio code, code.

Edit and code completion

Install code, then install sourcekit-lsp from source, nodejs is needed.

 install vscode sourcekit-lsp from source
git clone git@github.com:apple/sourcekit-lsp.git
cd Editors/vscode
npm run createDevPackage
code --install-extension out/sourcekit-lsp-vscode-dev.vsix

hello world

swift package manager allows to create example programs.

hello-world executable
swift package init --type executable
swift run
hello-world library
swift package init
swift build

read eval print loop, REPL

For details on the swift REPL, see here.

read eval print loop
> swift
Welcome to Swift version 5.3 (swift-5.3-RELEASE).
Type :help for assistance.
  1> 1+1
$R0: Int = 2