v4script

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v4script lets a Qt application run programs written in fifteen languages - from QBasic and Turbo Pascal classics to Go, C++, Java, C# and WebAssembly - inside the JavaScript engine that every Qt Qml installation already has. No compilers, no external processes, no native interpreters: one static library, a few lines of C++, and your users can script your application in the language they like.

v4script::Runtime runtime;
runtime.setOutput([](v4script::Stream, const QString& text) { std::cout << text.toStdString(); });

runtime.run("basic",  "FOR i = 1 TO 3: PRINT i * i;: NEXT");          //  1  4  9
runtime.run("pascal", "WriteLn('Pi = ', Pi:0:5);");                   // Pi = 3.14159
runtime.run("go",     "fmt.Println(strings.Repeat(\"Go\", 3))");       // GoGoGo

Why v4script

• 🧩 Fifteen languages, one engine. Every language runs in the same QJSEngine as JavaScript, shares its global object and can call JavaScript - and the other way round.
• 🔌 Your API in every language. Give programs a QObject and its methods become a Go package, a C or C++ header, a Java or C# class, a Pascal unit, Prolog predicates and Scheme procedures - with names and types in the conventions of each language.
• 🎯 Faithful behavior. The translated languages are checked against real implementations: Pascal prints numbers exactly as Free Pascal does, BASIC follows QBasic down to PRINT USING and RND, C has its own memory with real pointers, the C++ library gives the numbers of libstdc++'s <random> and the order of its hash tables, C# formats numbers and orders dictionaries as .NET does, WebAssembly passes the specification tests.
• 🛡️ Safe to embed. Programs see only what the application gives them: output, standard input, module files, a canvas. A watchdog stops runaway code, deep recursion is an error, not a crash.
• 🎨 Graphics included. QBasic SCREEN 13 and Pascal Graph draw on a canvas - into a QImage or a Qt Quick Canvas.
• 📦 Pick what you need. Embed all languages (about 14 MB of scripts, 7.4 MB minified) or just the few your application uses.

Supported languages

Language	Version	What runs	Implementation
Python	3	Python 3 (the subset of Skulpt)	Skulpt ae5f462
Lua	5.3	Lua 5.3	fengari 0.1.5
Prolog	ISO	ISO Prolog	Tau Prolog 0.3.4
Perl	5	Perl 5 (the subset of Perlito5)	Perlito5 9.028
PHP	7	PHP 7 (the subset of Uniter)	Uniter (phpruntime 9.3.0)
Go	1.22	Go with goroutines, channels, generics and a subset of the standard library	v4script 0.1.4
C	C17	C17 with its own linear memory and a subset of the C library	v4script 0.1.4
C++	C++17	C++17 over the memory of C: classes, templates, exceptions, lambdas and an STL that behaves as libstdc++	v4script 0.1.4
Java	21	Java 21 with records, pattern matching, threads, streams and a JDK subset	v4script 0.1.4
C#	12	C# 12 with generics, LINQ, records, patterns, async/await, threads and a .NET 8 subset	v4script 0.1.4
Forth	2012	Forth 2012, compatible with gforth	v4script 0.1.4
BASIC	QBasic 4.5	QBasic / QuickBASIC 4.5 with graphics	v4script 0.1.4
Pascal	FPC 3.2.2	Free Pascal 3.2.2 (objfpc): classes, exceptions, SysUtils, Math, StrUtils, Classes, Crt, Graph	v4script 0.1.4
WebAssembly	2.0	the WAT text format, .wast scripts, WASI	v4script 0.1.4
Scheme	R7RS	R7RS-small, SRFI 1, 13, 18, 69, full continuations	v4script 0.1.4

Languages marked v4script are translated into JavaScript by v4script's own translator; the others run in third-party interpreters written in JavaScript. Versions are available to the application too: v4script::languages() and v4script::version().

Coming next

The translator grows one language at a time, in this order: Kotlin, Rust, Swift, Dart, Scala, F#, Haskell, Erlang, Fortran, COBOL, Nim, Zig, x86 assemblers (NASM, FASM, TASM) and ASMX, Verilog, MASM, Ada, Common Lisp, the NES (ca65) and Z80 (sjasmplus) assemblers, CoffeeScript, the .NET IL assembler. See TODO for the plan and the known gaps.

Try it online

The playground runs all fifteen languages in the browser with the same scripts: pick an example - BASIC games and graphics, Pascal Graph, goroutines in Go, records in Java, LINQ in C#, call/cc in Scheme - or write your own program; it stays in your browser. How it works and how it differs from the Qt engine: playground.

Documentation

• ▶️ Playground - the languages in the browser, built for GitHub Pages with node tools/build-site.mjs
• 🚀 Getting started - build, try the examples and the v4run command-line runner
• 📚 Languages - what each language supports and how programs use the application's API
• 🔧 Embedding - CMake integration, the C++ API, host modules, graphics
• ⚙️ Internals - how the translator and the interpreters work on V4
• 🧪 Testing and development

All documentation: docs/.

Building

cmake -S . -B build -DCMAKE_PREFIX_PATH=<path to Qt>/<kit>
cmake --build build --parallel
ctest --test-dir build --output-on-failure

Requires Qt 6.4 or later (developed with 6.4.1), CMake 3.19 and a C++17 compiler. To use it in your project, add it as a subdirectory and link V4Script::V4Script - see embedding.

以上為 README 的開頭部分。其餘內容請閱讀原文。 檢視完整 README ↗