XFormsKit

A native XForms 1.1 engine in Objective-C, for macOS, iOS and Linux (GNUstep). It reads an XHTML+XForms document and runs it as a real native form: stock widgets, no web view, no JavaScript. The engine is a translation of XSLTForms; on top of it sit two native front ends and three apps — a viewer, a form designer and an iOS host.

macOS	Linux (GNUstep)	iOS

Get it

Download from Releases:

Platform	Download	Contains
macOS 11+ (designer 12+)	XFormsViewer-macOS-*.zip, XFormsDesigner-macOS-*.zip	Signed, notarized apps
Linux x86_64	XFormsKit-*.AppImage	Viewer + designer; opens a chooser (… designer, … form.xhtml go straight in)
iOS 15+	—	Build XFormsMobile from source

Every push also uploads unsigned builds to its Actions run.

Build from source:

# macOS / iOS
xcodebuild -project XFormsKit.xcodeproj -scheme XFormsViewer build
# Linux, with a GNUstep prefix (see docs/building.md)
make && make apps

Details: docs/building.md · docs/packaging.md.

What works

• XForms 1.1 core — models, instances (inline and @src), xf:bind with calculate / relevant / readonly / required / constraint / type, XPath 1.0 plus the XForms function library, XML Events, the action set (setvalue, insert, delete, toggle, dispatch, message, load, send, if / while / iterate), submission (XML, urlencoded, multipart, JSON/CSV; replace all / instance / text), repeats, groups, switch, dialogs.
• Every control — input, secret, textarea, output, select / select1 (all appearances, itemsets), range, upload, trigger, submit; date and time inputs.
• Conformance — all 458 W3C XForms 1.1 test cases pass, on macOS, iOS and GNUstep, in CI.
• Real forms — the 47 XSLTForms sample forms in Samples/ open and run, including SVG charts with live values, rich-text hints and host tables of controls.
• Designer — outline, palette, inspectors, XPath editor with highlighting, event console and submission tester, on macOS and GNUstep.

Limitations

• No JavaScript. A form that calls functions from a <script> needs them registered natively (+[XFXPath registerHostFunctionNamed:evaluator:]).
• No form server. The apps open documents from disk; submission works, but there is nothing to serve or store forms yet.
• GNUstep: dates display but cannot be edited until gnustep-gui gets an editable NSDatePicker (#22). The Linux build ships a patched gnustep-gui (the fixes live in the shared gnustep-patches repository — see the notes — upstreaming in #23).
• iOS: one control per row in the iOS idiom, not the desktop layout; no designer; no App Store or TestFlight build.
• Not implemented: XSLTForms extensions ajx:tabs, xf:tree, appearance="table" on groups and repeats; Android (#11).

Architecture

One portable engine, two front ends, three platforms.

block-beta
    columns 3
    desktop["Apps: XFormsViewer · XFormsDesigner"]:2
    mobile["App: XFormsMobile"]
    appkit["AppKit front end — XFFormView"]:2
    uikit["UIKit front end — XFFormViewController"]
    engine["XFormsKit engine — XFProcessor: models · binds · controls · actions · events · submission"]:3
    xpath["XPath 1.0 + XForms functions"]
    dom["XFDOM — XML tree"]
    svg["SVG · rich text"]
    macos["macOS — Cocoa"]
    linux["Linux — GNUstep + Opal"]
    ios["iOS — UIKit"]

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Each layer uses only the one below, and a column is a platform: the AppKit front end is one code base for macOS and GNUstep. The engine is identical everywhere, and the front ends hold no form logic — they render what the processor exposes and hand edits back. XFormsLauncher (not shown) only picks an app inside the AppImage.

flowchart LR
    doc["XHTML+XForms<br/>document"] --> processor["XFProcessor<br/>rebuild · recalculate<br/>revalidate · refresh"]
    processor <-->|"controls ⇄ setValue, activate"| frontend["Front end<br/>AppKit or UIKit"]
    frontend <-->|"native widgets ⇄ edits"| user(("User"))
    processor -->|"submission"| server[("HTTP")]

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Path	What
Sources/XFormsKit/	Engine: processor, model, controls, actions, events, submission
Sources/XFormsKit/XPath/ · DOM/ · SVG/ · RichText/	Portable subsystems
Sources/XFormsKit/AppKit/ · UIKit/	The two front ends
Sources/XFormsDesignKit/	The designer's editor as a framework, for the designer and other apps to host
Apps/	Viewer, designer, iOS app, AppImage launcher
Tests/ · TestSuite/	Unit tests, W3C conformance suite
Samples/	XSLTForms sample forms
docs/	Design notes, XSLTForms mapping and gap list

Documentation

• Building and packaging
• XSLTForms → XFormsKit class map and gap list
• iOS port plan · W3C suite as XCTests · Submission authentication
• GNUstep notes for Linux

License

LGPL 2.1.