Module xml 

XML and XHTML parsing for declarative UI definitions. XML and XHTML parsing for declarative UI definitions.

This module provides comprehensive XML parsing and manipulation for Azul’s XML-based UI format (.azul files). It supports:

• XHTML parsing: Parse HTML-like syntax into DOM structures
• CSS extraction: Extract <style> blocks and inline styles
• Component system: Define reusable UI components with arguments
• Hot reload: Track file changes and rebuild UI incrementally
• Error reporting: Detailed syntax error messages with line/column info

Examples

use azul_core::xml::{XmlNode, XmlParseOptions};

let xml = "<div>Hello</div>";
// let node = XmlNode::parse(xml)?;

Structs

CompactDomBuilder

Builder for arena-based DOM construction (FastDom). Builds two parallel Vecs (hierarchy + node_data) in a single DFS pass.

ComponentArgument

FFI-safe replacement for (ComponentArgumentName, ComponentArgumentType) tuple.

ComponentArgumentVec

ComponentArgumentVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentArguments

Holds the list of arguments and whether the component accepts text content. Used by the compile pipeline to generate Rust function signatures.

ComponentCallbackArg

A single argument in a callback signature.

ComponentCallbackArgVec

ComponentCallbackArgVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentCallbackSignature

Callback signature: return type + argument list.

ComponentDataField

A field in the component’s internal data model.

ComponentDataFieldVec

ComponentDataFieldVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentDataModel

A named data model (struct definition) for code generation.

ComponentDataModelVec

ComponentDataModelVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentDef

A component definition — the “class” / “template” of a component. Can come from Rust builtins, compiled widgets, JSON, or user creation in debugger.

ComponentDefVec

ComponentDefVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentEnumModel

A named enum model for code generation. Stored in ComponentLibrary::enum_models.

ComponentEnumModelVec

ComponentEnumModelVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentEnumVariant

A single variant in a component enum model.

ComponentEnumVariantVec

ComponentEnumVariantVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentFieldNamedValue

Named field value: (field_name, value) pair.

ComponentFieldNamedValueVec

ComponentFieldNamedValueVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentFieldOverride

An override for a single field in a component instance.

ComponentFieldOverrideVec

ComponentFieldOverrideVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentFieldTypeBox

Heap-allocated box for recursive ComponentFieldType (e.g. Option<String>). Uses raw pointer indirection to break the infinite size.

ComponentFieldValueBox

Heap-allocated box for recursive ComponentFieldValue (e.g. Some(value)). Uses raw pointer indirection to break the infinite size.

ComponentFieldValueVec

ComponentFieldValueVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentId

Identifies a component within a library collection. e.g. collection=“builtin”, name=“div” for the <div> element, or collection=“shadcn”, name=“avatar” for a custom component.

ComponentInstanceDefault

Default component instance for a StyledDom slot.

ComponentLibrary

A named collection of component definitions

ComponentLibraryVec

ComponentLibraryVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

ComponentMap

The component map — holds libraries with namespaced components.

CssMatcher

DomXml

Wrapper for the XML parser - necessary to easily create a Dom from XML without putting an XML solver into azul-core.

DuplicatedAttributeError

DuplicatedNamespaceError

ExternalResource

An external resource URL found in an XML/HTML document

ExternalResourceVec

ExternalResourceVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

InvalidCharError

InvalidCharMultipleError

InvalidQuoteError

InvalidSpaceError

InvalidStringError

MalformedHierarchyError

Error for mismatched open/close tags in XML hierarchy

MimeTypeHint

MIME type hint for an external resource

MissingTypeError

Wrapper for MissingType error data.

NonXmlCharError

RegisterComponentFn

Callback struct for registering individual components at startup.

RegisterComponentLibraryFn

Callback struct for registering entire component libraries at startup.

UnexpectedCloseTagError

UnknownEntityReferenceError

UnknownNamespaceError

UselessFunctionArgumentError

Wrapper for UselessFunctionArgument error data.

WhiteSpaceInComponentNameError

Wrapper for WhiteSpaceInComponentName error data.

WhiteSpaceInComponentTypeError

Wrapper for WhiteSpaceInComponentType error data.

Xml

XmlAttributeMap

Attributes of an XML node, such as ["color" => "blue"] in <button color="blue" />.

XmlNode

Represents one XML node tag

XmlNodeChildVec

XmlNodeChildVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

XmlNodeVec

XmlNodeVecSlice

C-compatible slice type for $struct_name. This is a non-owning view into a Vec’s data.

XmlQualifiedName

A namespace-qualified XML name (e.g. svg:rect has namespace "svg" and local name "rect").

XmlTagName

Tag of an XML node, such as the “button” in <button>Hello</button>.

XmlTextError

XmlTextPos

Enums

CompileError

Error that can happen from the translation from XML code to Rust code - stringified, since it is only used for printing and is not exposed in the public API

CompileTarget

The target language for code compilation

ComponentArgumentVecDestructor

ComponentCallbackArgVecDestructor

ComponentDataFieldVecDestructor

ComponentDataModelVecDestructor

ComponentDefVecDestructor

ComponentDefaultValue

Default value for a component field.

ComponentEnumModelVecDestructor

ComponentEnumVariantVecDestructor

ComponentError

ComponentFieldNamedValueVecDestructor

ComponentFieldOverrideVecDestructor

ComponentFieldType

Rich type descriptor for a component field. Replaces the old AzString type names (“String”, “bool”, etc.) with a structured enum that the debugger can use for type-aware editing.

ComponentFieldValue

Runtime value for a component field — the “instance” counterpart to ComponentFieldType (which is the “class” / type descriptor).

ComponentFieldValueSource

How a field value is sourced at the instance level.

ComponentFieldValueVecDestructor

ComponentLibraryVecDestructor

ComponentParseError

ComponentSource

Source of a component definition — determines whether it can be exported

DomXmlParseError

DynamicItem

Item of a split string - either a variable name (with optional format spec) or a string

ExternalResourceKind

Classification of an external resource referenced in HTML/XML

ExternalResourceVecDestructor

OptionComponentArgument

OptionComponentCallbackArg

OptionComponentDataField

OptionComponentDataModel

OptionComponentDef

OptionComponentDefaultValue

OptionComponentEnumModel

OptionComponentEnumVariant

OptionComponentFieldNamedValue

OptionComponentFieldOverride

OptionComponentFieldValue

OptionComponentLibrary

OptionExternalResource

OptionMimeTypeHint

OptionXmlNode

OptionXmlNodeChild

RenderDomError

ResultStringCompileError

ResultStyledDomRenderDomError

ResultXmlXmlError

XmlError

XmlNodeChild

Represents a child of an XML node - either an element or text

XmlNodeChildVecDestructor

XmlNodeType

Type of an XML node in the parsed tree.

XmlNodeVecDestructor

XmlParseError

XmlStreamError

c_void

Opaque void type for FFI pointers. Uses a custom definition instead of core::ffi::c_void for #[repr(C)] compatibility in the generated API.

Functions

compile_body_node_to_rust_code

compile_component

find_attribute

format_args_dynamic

Given a string and a key => value mapping, replaces parts of the string with the value, i.e.:

get_body_node

Find the one and only <body> node, return error if there is no app node or there are multiple app nodes

get_html_node

Find the one and only <body> node, return error if there is no app node or there are multiple app nodes

get_item

Given a root node, traverses along the hierarchy, and returns a mutable reference to the last child node of the root node

normalize_casing

Normalizes input such as abcDef, AbcDef, abc-def to the normalized form of abc_def

parse_bool

Parses a string (“true” or “false”)

prepare_string

register_builtin_components

Register the 52 built-in HTML element components.

split_dynamic_string

Splits a string into formatting arguments, supporting format specifiers like {var:?}

str_to_dom

Parses an XML string and returns a StyledDom with the components instantiated in the <app></app>

str_to_dom_unstyled

Parses XML nodes and returns a Dom with CSS stylesheets attached (but not applied).

str_to_rust_code

Parses an XML string and returns a String, which contains the Rust source code (i.e. it compiles the XML to valid Rust)

tag_to_node_type

Map a builtin tag name to its corresponding NodeType. Falls back to NodeType::Div for unknown tags.

user_defined_compile_fn

Default compile function for user-defined (JSON-imported) components.

user_defined_render_fn

Default render function for user-defined (JSON-imported) components.

Type Aliases

ComponentArgumentVecDestructorType

ComponentCallbackArgVecDestructorType

ComponentCompileFn

Compile function type: takes component definition + target language + data model, returns source code.

ComponentDataFieldVecDestructorType

ComponentDataModelVecDestructorType

ComponentDefVecDestructorType

ComponentEnumModelVecDestructorType

ComponentEnumVariantVecDestructorType

ComponentFieldNamedValueVecDestructorType

ComponentFieldOverrideVecDestructorType

ComponentFieldValueVecDestructorType

ComponentLibraryVecDestructorType

ComponentRenderFn

Render function type: takes component definition + data model (with current values in default_value fields) + component map for recursive sub-component instantiation, returns StyledDom.

ExternalResourceVecDestructorType

RegisterComponentFnType

Raw function pointer type that returns a single ComponentDef when called. Used as the cb field in RegisterComponentFn.

RegisterComponentLibraryFnType

Raw function pointer type that returns a complete ComponentLibrary when called. Used as the cb field in RegisterComponentLibraryFn.

SyntaxError

Error that can occur during XML parsing or hot-reload.

XmlNodeChildVecDestructorType

XmlNodeVecDestructorType

XmlTextContent

(Unparsed) text content of an XML node, such as the “Hello” in <button>Hello</button>.