fop-core

XSL-FO document parser and property system for the Apache FOP Rust implementation. This crate reads XSL-FO XML and produces a typed, arena-allocated FO tree with property inheritance.

Features

294 XSL-FO 1.1 properties as a compile-time enum (PropertyId)
Property inheritance with parent chain lookup and caching
Arena-allocated FO tree with index-based handles (no Rc<RefCell<>>)
SAX-like streaming parser built on quick-xml
29 FO element types covering pages, blocks, tables, lists, graphics
Shorthand expansion for margin, padding, border shorthands
Nesting validation per XSL-FO 1.1 specification rules

Usage

use fop_core::FoTreeBuilder;
use std::io::Cursor;

let xml = r#"<?xml version="1.0"?>
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
    <fo:layout-master-set>
        <fo:simple-page-master master-name="A4"
            page-width="210mm" page-height="297mm">
            <fo:region-body margin="1in"/>
        </fo:simple-page-master>
    </fo:layout-master-set>
    <fo:page-sequence master-reference="A4">
        <fo:flow flow-name="xsl-region-body">
            <fo:block font-size="14pt">Hello, FOP!</fo:block>
        </fo:flow>
    </fo:page-sequence>
</fo:root>"#;

let builder = FoTreeBuilder::new();
let arena = builder.parse(Cursor::new(xml)).unwrap();

for (id, node) in arena.iter() {
    println!("{}: {}", id, node.data.element_name());
}

Architecture

Modules

`properties/` - Property System

File	Lines	Description
`property_id.rs`	1,210	`PropertyId` enum with 294 XSL-FO properties
`property_value.rs`	177	`PropertyValue` enum (Length, Color, Enum, String...)
`property_list.rs`	275	`PropertyList` with inheritance and caching
`shorthand.rs`	268	Shorthand expansion (margin -> 4 sides)

`tree/` - FO Tree

File	Lines	Description
`arena.rs`	276	`FoArena` index-based allocator
`node.rs`	327	`FoNode`, `FoNodeData` (29 element variants)
`builder.rs`	426	`FoTreeBuilder` SAX-like parser
`validation.rs`	195	`NestingValidator` spec compliance

`xml/` - XML Parsing

File	Lines	Description
`parser.rs`	227	`XmlParser` wrapper around quick-xml
`namespace.rs`	80	XSL-FO, FOX, SVG namespace handling

`elements/` - Element Definitions

File	Lines	Description
`table.rs`	284	Table element structures
`list.rs`	284	List element structures

Total: 4,157 lines across 16 files

Supported FO Elements (29 types)

Page Layout: Root, LayoutMasterSet, SimplePageMaster, RegionBody, RegionBefore, RegionAfter

Page Sequence: PageSequence, Flow, StaticContent

Block Level: Block, BlockContainer

Inline Level: Inline, Character, PageNumber, PageNumberCitation

Table: Table, TableColumn, TableHeader, TableFooter, TableBody, TableRow, TableCell

List: ListBlock, ListItem, ListItemLabel, ListItemBody

Other: ExternalGraphic, BasicLink, Leader, Wrapper

Property Inheritance

Properties are looked up through a parent chain. Inheritable properties (like font-size, color) automatically propagate from parent to child:

use fop_core::{PropertyId, PropertyValue, PropertyList};
use fop_types::Length;

let mut parent = PropertyList::new();
parent.set(PropertyId::FontSize, PropertyValue::Length(Length::from_pt(14.0)));

let child = PropertyList::with_parent(&parent);
// child inherits font-size=14pt from parent
let size = child.get(PropertyId::FontSize).unwrap();

Tests

41 unit tests covering:

Property ID name/number mapping
Property value parsing (lengths, colors, enums)
Property inheritance chains
Shorthand expansion (margin, padding, border)
XSL-FO document parsing (simple and complex)
Element nesting validation
XML namespace handling
Arena allocator operations

Dependencies

fop-types (internal)
quick-xml 0.39 - XML parsing
thiserror 2.0 - Error handling
log 0.4 - Logging

fop-core 0.1.0