LispKit is a framework for building Lisp-based extension and scripting languages for macOS and iOS applications. LispKit is fully written in the programming language Swift. LispKit implements a core language based on the R7RS (small) Scheme standard. It is extensible, allowing the inclusion of new native libraries written in Swift, of new libraries written in Scheme, as well as custom modifications of the core environment consisting of a compiler, a virtual machine as well as the core libraries.
The NumericalScheme demo showcases how to create a derived LispKit interpreter that inherits everything from LispKit (without code duplication) and defines a new native as well as Scheme-based library.
The iOS version of the LispKit framework supports all libraries except for
(lispkit system os).
(lispkit draw) works consistently across iOS and macOS but does not support color
lists on iOS. In general, the differences between the macOS and iOS version of the framework
are minor, but require documentation. Interestingly, the iPhone 12 Pro (2020) seems to consistently
outperform the MacBook Pro 16" (2019) for simple LispKit benchmarks.
LispPad implements a simple, lightweight, integrated development environment for LispKit on macOS with a Cocoa-based UI. The LispPad Library Reference documents the core LispPad and LispKit libraries in PDF form. On iOS, application LispPad Go provides a simple Scheme IDE based on LispKit. The source code of LispPad Go is available on GitHub. A much simpler command-line tool for iOS is included in the LispKit framework itself (see below).
LispKit provides support for the following core features, many of which are based on R7RS:
(lispkit system os),
(lispkit draw turtle),
(lispkit archive zip),
(lispkit sxml xml),
(lispkit sxml html), and
LispKit is incompatible or incomplete with respect to the following R7RS features:
syntax-rulesare not matched based on their definition but their symbol identity
#;do not always work as in other Scheme dialects.
The following SRFI libraries have been ported to LispKit and are included in the framework:
=>in case clauses
The project defines four different targets:
LispKit consists of:
Details can be found in the LispKit Wiki.
This project includes a command-line tool, called the LispKit Shell, for executing LispKit applications in the terminal. It can be used to try out and experiment with the LispKit framework. The command-line tool can also be used interactively as a read-eval-print loop. The read-eval-print loop parses the entered LispKit expression, compiles it to bytecode, executes it, and displays the result.
First, clone the LispKit repository via
git. The following command will create a directory
> git clone https://github.com/objecthub/swift-lispkit.git Cloning into 'swift-lispkit'... remote: Enumerating objects: 7020, done. remote: Counting objects: 100% (365/365), done. remote: Compressing objects: 100% (349/349), done. remote: Total 7020 (delta 174), reused 201 (delta 10), pack-reused 6655 Receiving objects: 100% (7020/7020), 11.29 MiB | 5.20 MiB/s, done. Resolving deltas: 100% (4853/4853), done.
Next, switch to Xcode and build the LispKit command-line tool via scheme
> open LispKit.xcodeproj
A debug binary can be built in the following way:
> cd swift-lispkit > swift build -Xswiftc "-D" -Xswiftc "SPM" Fetching https://github.com/objecthub/swift-markdownkit.git from cache Fetching https://github.com/objecthub/swift-numberkit.git from cache Fetching https://github.com/objecthub/swift-sqliteexpress.git from cache Fetching https://github.com/objecthub/swift-commandlinekit.git from cache Fetching https://github.com/weichsel/ZIPFoundation.git from cache Cloning https://github.com/objecthub/swift-sqliteexpress.git Resolving https://github.com/objecthub/swift-sqliteexpress.git at 1.0.3 Cloning https://github.com/weichsel/ZIPFoundation.git Resolving https://github.com/weichsel/ZIPFoundation.git at 0.9.12 Cloning https://github.com/objecthub/swift-markdownkit.git Resolving https://github.com/objecthub/swift-markdownkit.git at 1.0.5 Cloning https://github.com/objecthub/swift-numberkit.git Resolving https://github.com/objecthub/swift-numberkit.git at 2.3.9 Cloning https://github.com/objecthub/swift-commandlinekit.git Resolving https://github.com/objecthub/swift-commandlinekit.git at 0.3.3 [180/180] Linking LispKitRepl
The debug binary can now be run like this:
`.build/debug/LispKitRepl -r Sources/LispKit/Resources -d LispKit`
For experimentation with a new resources directory (e.g. containing new or modified Scheme libraries),
the binary can also be run via
.build/debug/LispKitRepl -d LispKit assuming that directory
~/Documents/LispKit contains a copy of the
There is also a
Makefile which provides convenience build rules. Building and running the REPL can
be achieved, e.g. by invoking
make run (for the debug REPL) or
make repl (for the release REPL).
Details for building such release binaries can be looked up in the
Within Xcode, switch the scheme to the target LispKitRepl iOS and build and run the project. By default, this will invoke the iOS simulator and run an application "LispKitRepl iOS". The application has a chat-inspired UI in which Scheme commands can be entered at the bottom and sent to the interpreter via the "arrow-up" button. The interpreter will then execute the command and print the result in the console area above. There is a single button with a trash can in the toolbar for resetting the interpreter. This button turns into a button for cancelling running programs (e.g. if there is an infinite loop or other deadlock).
The following technologies are needed to build the components of the LispKit framework. For building the command-line tool, all that is needed is the Swift Package Manager. For compiling the framework and trying the command-line tool directly in Xcode, the Swift Package Manager is not needed.
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