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//! Rust source-code emitter for parsed CSS.
//!
//! Produces a `const CSS: Css = ...;` literal plus a minimal `Cargo.toml` and
//! `src/main.rs` skeleton suitable for `cargo build` against `azul`.
use alloc::{format, string::String, string::ToString, vec, vec::Vec};
use super::{CodegenBackend, GeneratedFile};
use crate::{
css::{
AttributeMatchOp, Css, CssAttributeSelector, CssDeclaration, CssNthChildPattern,
CssNthChildSelector, CssPath, CssPathPseudoSelector, CssPathSelector, DynamicCssProperty,
NodeTypeTag,
},
props::property::format_static_css_prop,
};
/// Emits Rust source code for a parsed CSS stylesheet.
pub struct RustBackend;
impl CodegenBackend for RustBackend {
fn lang(&self) -> &'static str {
"rust"
}
fn emit_css(&self, css: &Css) -> String {
css_to_rust_code(css)
fn emit_project(&self, css: &Css) -> Vec<GeneratedFile> {
let css_literal = css_to_rust_code(css);
let main_rs = format!(
"use azul::prelude::*;\r\n\r\n{css_literal}\r\n\r\nfn main() {{\r\n \
println!(\"Generated stylesheet contains {{}} rule(s)\", \
CSS.rules.as_ref().len());\r\n}}\r\n",
);
let cargo_toml = "[package]\r\n\
name = \"azul-generated-app\"\r\n\
version = \"0.1.0\"\r\n\
edition = \"2021\"\r\n\
\r\n\
[dependencies]\r\n\
azul = \"0.0.7\"\r\n"
.to_string();
vec![
GeneratedFile {
path: "Cargo.toml".to_string(),
contents: cargo_toml,
path: "src/main.rs".to_string(),
contents: main_rs,
]
/// Render a parsed [`Css`] as Rust source code (a `const CSS: Css = ...;`).
pub fn css_to_rust_code(css: &Css) -> String {
let mut output = String::new();
output.push_str("const CSS: Css = Css {\r\n");
output.push_str("\trules: [\r\n");
for block in css.rules.iter() {
output.push_str("\t\tCssRuleBlock {\r\n");
output.push_str(&format!(
"\t\t\tpath: {},\r\n",
print_block_path(&block.path, 3)
));
"\t\t\tpriority: {},\r\n",
block.priority,
output.push_str("\t\t\tdeclarations: [\r\n");
for declaration in block.declarations.iter() {
"\t\t\t\t{},\r\n",
print_declaration(declaration, 4)
output.push_str("\t\t\t]\r\n");
output.push_str("\t\t},\r\n");
output.push_str("\t]\r\n");
output.push_str("};");
output.replace("\t", " ")
pub fn format_node_type(n: &NodeTypeTag) -> &'static str {
match n {
// Document structure
NodeTypeTag::Html => "NodeTypeTag::Html",
NodeTypeTag::Head => "NodeTypeTag::Head",
NodeTypeTag::Body => "NodeTypeTag::Body",
// Block elements
NodeTypeTag::Div => "NodeTypeTag::Div",
NodeTypeTag::P => "NodeTypeTag::P",
NodeTypeTag::Article => "NodeTypeTag::Article",
NodeTypeTag::Section => "NodeTypeTag::Section",
NodeTypeTag::Nav => "NodeTypeTag::Nav",
NodeTypeTag::Aside => "NodeTypeTag::Aside",
NodeTypeTag::Header => "NodeTypeTag::Header",
NodeTypeTag::Footer => "NodeTypeTag::Footer",
NodeTypeTag::Main => "NodeTypeTag::Main",
NodeTypeTag::Figure => "NodeTypeTag::Figure",
NodeTypeTag::FigCaption => "NodeTypeTag::FigCaption",
// Headings
NodeTypeTag::H1 => "NodeTypeTag::H1",
NodeTypeTag::H2 => "NodeTypeTag::H2",
NodeTypeTag::H3 => "NodeTypeTag::H3",
NodeTypeTag::H4 => "NodeTypeTag::H4",
NodeTypeTag::H5 => "NodeTypeTag::H5",
NodeTypeTag::H6 => "NodeTypeTag::H6",
// Text formatting
NodeTypeTag::Br => "NodeTypeTag::Br",
NodeTypeTag::Hr => "NodeTypeTag::Hr",
NodeTypeTag::Pre => "NodeTypeTag::Pre",
NodeTypeTag::BlockQuote => "NodeTypeTag::BlockQuote",
NodeTypeTag::Address => "NodeTypeTag::Address",
NodeTypeTag::Details => "NodeTypeTag::Details",
NodeTypeTag::Summary => "NodeTypeTag::Summary",
NodeTypeTag::Dialog => "NodeTypeTag::Dialog",
// List elements
NodeTypeTag::Ul => "NodeTypeTag::Ul",
NodeTypeTag::Ol => "NodeTypeTag::Ol",
NodeTypeTag::Li => "NodeTypeTag::Li",
NodeTypeTag::Dl => "NodeTypeTag::Dl",
NodeTypeTag::Dt => "NodeTypeTag::Dt",
NodeTypeTag::Dd => "NodeTypeTag::Dd",
NodeTypeTag::Menu => "NodeTypeTag::Menu",
NodeTypeTag::MenuItem => "NodeTypeTag::MenuItem",
NodeTypeTag::Dir => "NodeTypeTag::Dir",
// Table elements
NodeTypeTag::Table => "NodeTypeTag::Table",
NodeTypeTag::Caption => "NodeTypeTag::Caption",
NodeTypeTag::THead => "NodeTypeTag::THead",
NodeTypeTag::TBody => "NodeTypeTag::TBody",
NodeTypeTag::TFoot => "NodeTypeTag::TFoot",
NodeTypeTag::Tr => "NodeTypeTag::Tr",
NodeTypeTag::Th => "NodeTypeTag::Th",
NodeTypeTag::Td => "NodeTypeTag::Td",
NodeTypeTag::ColGroup => "NodeTypeTag::ColGroup",
NodeTypeTag::Col => "NodeTypeTag::Col",
// Form elements
NodeTypeTag::Form => "NodeTypeTag::Form",
NodeTypeTag::FieldSet => "NodeTypeTag::FieldSet",
NodeTypeTag::Legend => "NodeTypeTag::Legend",
NodeTypeTag::Label => "NodeTypeTag::Label",
NodeTypeTag::Input => "NodeTypeTag::Input",
NodeTypeTag::Button => "NodeTypeTag::Button",
NodeTypeTag::Select => "NodeTypeTag::Select",
NodeTypeTag::OptGroup => "NodeTypeTag::OptGroup",
NodeTypeTag::SelectOption => "NodeTypeTag::SelectOption",
NodeTypeTag::TextArea => "NodeTypeTag::TextArea",
NodeTypeTag::Output => "NodeTypeTag::Output",
NodeTypeTag::Progress => "NodeTypeTag::Progress",
NodeTypeTag::Meter => "NodeTypeTag::Meter",
NodeTypeTag::DataList => "NodeTypeTag::DataList",
// Inline elements
NodeTypeTag::Span => "NodeTypeTag::Span",
NodeTypeTag::A => "NodeTypeTag::A",
NodeTypeTag::Em => "NodeTypeTag::Em",
NodeTypeTag::Strong => "NodeTypeTag::Strong",
NodeTypeTag::B => "NodeTypeTag::B",
NodeTypeTag::I => "NodeTypeTag::I",
NodeTypeTag::U => "NodeTypeTag::U",
NodeTypeTag::S => "NodeTypeTag::S",
NodeTypeTag::Mark => "NodeTypeTag::Mark",
NodeTypeTag::Del => "NodeTypeTag::Del",
NodeTypeTag::Ins => "NodeTypeTag::Ins",
NodeTypeTag::Code => "NodeTypeTag::Code",
NodeTypeTag::Samp => "NodeTypeTag::Samp",
NodeTypeTag::Kbd => "NodeTypeTag::Kbd",
NodeTypeTag::Var => "NodeTypeTag::Var",
NodeTypeTag::Cite => "NodeTypeTag::Cite",
NodeTypeTag::Dfn => "NodeTypeTag::Dfn",
NodeTypeTag::Abbr => "NodeTypeTag::Abbr",
NodeTypeTag::Acronym => "NodeTypeTag::Acronym",
NodeTypeTag::Q => "NodeTypeTag::Q",
NodeTypeTag::Time => "NodeTypeTag::Time",
NodeTypeTag::Sub => "NodeTypeTag::Sub",
NodeTypeTag::Sup => "NodeTypeTag::Sup",
NodeTypeTag::Small => "NodeTypeTag::Small",
NodeTypeTag::Big => "NodeTypeTag::Big",
NodeTypeTag::Bdo => "NodeTypeTag::Bdo",
NodeTypeTag::Bdi => "NodeTypeTag::Bdi",
NodeTypeTag::Wbr => "NodeTypeTag::Wbr",
NodeTypeTag::Ruby => "NodeTypeTag::Ruby",
NodeTypeTag::Rt => "NodeTypeTag::Rt",
NodeTypeTag::Rtc => "NodeTypeTag::Rtc",
NodeTypeTag::Rp => "NodeTypeTag::Rp",
NodeTypeTag::Data => "NodeTypeTag::Data",
// Embedded content
NodeTypeTag::Canvas => "NodeTypeTag::Canvas",
NodeTypeTag::Object => "NodeTypeTag::Object",
NodeTypeTag::Param => "NodeTypeTag::Param",
NodeTypeTag::Embed => "NodeTypeTag::Embed",
NodeTypeTag::Audio => "NodeTypeTag::Audio",
NodeTypeTag::Video => "NodeTypeTag::Video",
NodeTypeTag::Source => "NodeTypeTag::Source",
NodeTypeTag::Track => "NodeTypeTag::Track",
NodeTypeTag::Map => "NodeTypeTag::Map",
NodeTypeTag::Area => "NodeTypeTag::Area",
NodeTypeTag::Svg => "NodeTypeTag::Svg",
NodeTypeTag::SvgPath => "NodeTypeTag::SvgPath",
NodeTypeTag::SvgCircle => "NodeTypeTag::SvgCircle",
NodeTypeTag::SvgRect => "NodeTypeTag::SvgRect",
NodeTypeTag::SvgEllipse => "NodeTypeTag::SvgEllipse",
NodeTypeTag::SvgLine => "NodeTypeTag::SvgLine",
NodeTypeTag::SvgPolygon => "NodeTypeTag::SvgPolygon",
NodeTypeTag::SvgPolyline => "NodeTypeTag::SvgPolyline",
NodeTypeTag::SvgG => "NodeTypeTag::SvgG",
// SVG container elements
NodeTypeTag::SvgDefs => "NodeTypeTag::SvgDefs",
NodeTypeTag::SvgSymbol => "NodeTypeTag::SvgSymbol",
NodeTypeTag::SvgUse => "NodeTypeTag::SvgUse",
NodeTypeTag::SvgSwitch => "NodeTypeTag::SvgSwitch",
// SVG text elements
NodeTypeTag::SvgText => "NodeTypeTag::SvgText",
NodeTypeTag::SvgTspan => "NodeTypeTag::SvgTspan",
NodeTypeTag::SvgTextPath => "NodeTypeTag::SvgTextPath",
// SVG paint server elements
NodeTypeTag::SvgLinearGradient => "NodeTypeTag::SvgLinearGradient",
NodeTypeTag::SvgRadialGradient => "NodeTypeTag::SvgRadialGradient",
NodeTypeTag::SvgStop => "NodeTypeTag::SvgStop",
NodeTypeTag::SvgPattern => "NodeTypeTag::SvgPattern",
// SVG clipping/masking elements
NodeTypeTag::SvgClipPathElement => "NodeTypeTag::SvgClipPathElement",
NodeTypeTag::SvgMask => "NodeTypeTag::SvgMask",
// SVG filter elements
NodeTypeTag::SvgFilter => "NodeTypeTag::SvgFilter",
NodeTypeTag::SvgFeBlend => "NodeTypeTag::SvgFeBlend",
NodeTypeTag::SvgFeColorMatrix => "NodeTypeTag::SvgFeColorMatrix",
NodeTypeTag::SvgFeComponentTransfer => "NodeTypeTag::SvgFeComponentTransfer",
NodeTypeTag::SvgFeComposite => "NodeTypeTag::SvgFeComposite",
NodeTypeTag::SvgFeConvolveMatrix => "NodeTypeTag::SvgFeConvolveMatrix",
NodeTypeTag::SvgFeDiffuseLighting => "NodeTypeTag::SvgFeDiffuseLighting",
NodeTypeTag::SvgFeDisplacementMap => "NodeTypeTag::SvgFeDisplacementMap",
NodeTypeTag::SvgFeDistantLight => "NodeTypeTag::SvgFeDistantLight",
NodeTypeTag::SvgFeDropShadow => "NodeTypeTag::SvgFeDropShadow",
NodeTypeTag::SvgFeFlood => "NodeTypeTag::SvgFeFlood",
NodeTypeTag::SvgFeFuncR => "NodeTypeTag::SvgFeFuncR",
NodeTypeTag::SvgFeFuncG => "NodeTypeTag::SvgFeFuncG",
NodeTypeTag::SvgFeFuncB => "NodeTypeTag::SvgFeFuncB",
NodeTypeTag::SvgFeFuncA => "NodeTypeTag::SvgFeFuncA",
NodeTypeTag::SvgFeGaussianBlur => "NodeTypeTag::SvgFeGaussianBlur",
NodeTypeTag::SvgFeImage => "NodeTypeTag::SvgFeImage",
NodeTypeTag::SvgFeMerge => "NodeTypeTag::SvgFeMerge",
NodeTypeTag::SvgFeMergeNode => "NodeTypeTag::SvgFeMergeNode",
NodeTypeTag::SvgFeMorphology => "NodeTypeTag::SvgFeMorphology",
NodeTypeTag::SvgFeOffset => "NodeTypeTag::SvgFeOffset",
NodeTypeTag::SvgFePointLight => "NodeTypeTag::SvgFePointLight",
NodeTypeTag::SvgFeSpecularLighting => "NodeTypeTag::SvgFeSpecularLighting",
NodeTypeTag::SvgFeSpotLight => "NodeTypeTag::SvgFeSpotLight",
NodeTypeTag::SvgFeTile => "NodeTypeTag::SvgFeTile",
NodeTypeTag::SvgFeTurbulence => "NodeTypeTag::SvgFeTurbulence",
// SVG marker/image elements
NodeTypeTag::SvgMarker => "NodeTypeTag::SvgMarker",
NodeTypeTag::SvgImage => "NodeTypeTag::SvgImage",
NodeTypeTag::SvgForeignObject => "NodeTypeTag::SvgForeignObject",
// SVG descriptive elements
NodeTypeTag::SvgTitle => "NodeTypeTag::SvgTitle",
NodeTypeTag::SvgDesc => "NodeTypeTag::SvgDesc",
NodeTypeTag::SvgMetadata => "NodeTypeTag::SvgMetadata",
NodeTypeTag::SvgA => "NodeTypeTag::SvgA",
NodeTypeTag::SvgView => "NodeTypeTag::SvgView",
NodeTypeTag::SvgStyle => "NodeTypeTag::SvgStyle",
NodeTypeTag::SvgScript => "NodeTypeTag::SvgScript",
// SVG animation elements
NodeTypeTag::SvgAnimate => "NodeTypeTag::SvgAnimate",
NodeTypeTag::SvgAnimateMotion => "NodeTypeTag::SvgAnimateMotion",
NodeTypeTag::SvgAnimateTransform => "NodeTypeTag::SvgAnimateTransform",
NodeTypeTag::SvgSet => "NodeTypeTag::SvgSet",
NodeTypeTag::SvgMpath => "NodeTypeTag::SvgMpath",
// Metadata
NodeTypeTag::Title => "NodeTypeTag::Title",
NodeTypeTag::Meta => "NodeTypeTag::Meta",
NodeTypeTag::Link => "NodeTypeTag::Link",
NodeTypeTag::Script => "NodeTypeTag::Script",
NodeTypeTag::Style => "NodeTypeTag::Style",
NodeTypeTag::Base => "NodeTypeTag::Base",
// Content elements
NodeTypeTag::Text => "NodeTypeTag::Text",
NodeTypeTag::Img => "NodeTypeTag::Img",
NodeTypeTag::VirtualView => "NodeTypeTag::VirtualView",
NodeTypeTag::Icon => "NodeTypeTag::Icon",
NodeTypeTag::GeolocationProbe => "NodeTypeTag::GeolocationProbe",
// Pseudo-elements
NodeTypeTag::Before => "NodeTypeTag::Before",
NodeTypeTag::After => "NodeTypeTag::After",
NodeTypeTag::Marker => "NodeTypeTag::Marker",
NodeTypeTag::Placeholder => "NodeTypeTag::Placeholder",
pub fn print_block_path(path: &CssPath, tabs: usize) -> String {
let t = String::from(" ").repeat(tabs);
let t1 = String::from(" ").repeat(tabs + 1);
format!(
"CssPath {{\r\n{}selectors: {}\r\n{}}}",
t1,
format_selectors(path.selectors.as_ref(), tabs + 1),
t
)
pub fn format_selectors(selectors: &[CssPathSelector], tabs: usize) -> String {
let selectors_formatted = selectors
.iter()
.map(|s| format!("{}{},", t1, format_single_selector(s, tabs + 1)))
.collect::<Vec<String>>()
.join("\r\n");
format!("vec![\r\n{}\r\n{}].into()", selectors_formatted, t)
pub fn format_single_selector(p: &CssPathSelector, _tabs: usize) -> String {
match p {
CssPathSelector::Global => "CssPathSelector::Global".to_string(),
CssPathSelector::Type(ntp) => format!("CssPathSelector::Type({})", format_node_type(ntp)),
CssPathSelector::Class(class) => {
format!("CssPathSelector::Class(String::from({:?}))", class)
CssPathSelector::Id(id) => format!("CssPathSelector::Id(String::from({:?}))", id),
CssPathSelector::PseudoSelector(cps) => format!(
"CssPathSelector::PseudoSelector({})",
format_pseudo_selector_type(cps)
),
CssPathSelector::Attribute(a) => format!(
"CssPathSelector::Attribute({})",
format_attribute_selector(a)
CssPathSelector::DirectChildren => "CssPathSelector::DirectChildren".to_string(),
CssPathSelector::Children => "CssPathSelector::Children".to_string(),
CssPathSelector::AdjacentSibling => "CssPathSelector::AdjacentSibling".to_string(),
CssPathSelector::GeneralSibling => "CssPathSelector::GeneralSibling".to_string(),
pub fn format_pseudo_selector_type(p: &CssPathPseudoSelector) -> String {
CssPathPseudoSelector::First => "CssPathPseudoSelector::First".to_string(),
CssPathPseudoSelector::Last => "CssPathPseudoSelector::Last".to_string(),
CssPathPseudoSelector::NthChild(n) => format!(
"CssPathPseudoSelector::NthChild({})",
format_nth_child_selector(n)
CssPathPseudoSelector::Hover => "CssPathPseudoSelector::Hover".to_string(),
CssPathPseudoSelector::Active => "CssPathPseudoSelector::Active".to_string(),
CssPathPseudoSelector::Focus => "CssPathPseudoSelector::Focus".to_string(),
CssPathPseudoSelector::Backdrop => "CssPathPseudoSelector::Backdrop".to_string(),
CssPathPseudoSelector::Lang(lang) => format!(
"CssPathPseudoSelector::Lang(AzString::from_const_str(\"{}\"))",
lang.as_str()
CssPathPseudoSelector::Dragging => "CssPathPseudoSelector::Dragging".to_string(),
CssPathPseudoSelector::DragOver => "CssPathPseudoSelector::DragOver".to_string(),
pub fn format_attribute_selector(a: &CssAttributeSelector) -> String {
let value = match a.value.as_ref() {
Some(v) => format!(
"OptionString::Some(AzString::from_const_str({:?}))",
v.as_str()
None => "OptionString::None".to_string(),
"CssAttributeSelector {{ name: AzString::from_const_str({:?}), op: {}, value: {} }}",
a.name.as_str(),
format_attribute_match_op(&a.op),
value
pub fn format_attribute_match_op(op: &AttributeMatchOp) -> String {
match op {
AttributeMatchOp::Exists => "AttributeMatchOp::Exists".to_string(),
AttributeMatchOp::Eq => "AttributeMatchOp::Eq".to_string(),
AttributeMatchOp::Includes => "AttributeMatchOp::Includes".to_string(),
AttributeMatchOp::DashMatch => "AttributeMatchOp::DashMatch".to_string(),
AttributeMatchOp::Prefix => "AttributeMatchOp::Prefix".to_string(),
AttributeMatchOp::Suffix => "AttributeMatchOp::Suffix".to_string(),
AttributeMatchOp::Substring => "AttributeMatchOp::Substring".to_string(),
pub fn format_nth_child_selector(n: &CssNthChildSelector) -> String {
CssNthChildSelector::Number(num) => format!("CssNthChildSelector::Number({})", num),
CssNthChildSelector::Even => "CssNthChildSelector::Even".to_string(),
CssNthChildSelector::Odd => "CssNthChildSelector::Odd".to_string(),
CssNthChildSelector::Pattern(CssNthChildPattern {
pattern_repeat,
offset,
}) => format!(
"CssNthChildSelector::Pattern(CssNthChildPattern {{ pattern_repeat: {}, offset: {} }})",
pattern_repeat, offset
pub fn print_declaration(decl: &CssDeclaration, tabs: usize) -> String {
match decl {
CssDeclaration::Static(s) => format!(
"CssDeclaration::Static({})",
format_static_css_prop(s, tabs)
CssDeclaration::Dynamic(d) => format!(
"CssDeclaration::Dynamic({})",
format_dynamic_css_prop(d, tabs)
pub fn format_dynamic_css_prop(decl: &DynamicCssProperty, tabs: usize) -> String {
"DynamicCssProperty {{\r\n{} dynamic_id: {:?},\r\n{} default_value: {},\r\n{}}}",
t,
decl.dynamic_id,
format_static_css_prop(&decl.default_value, tabs + 1),
#[cfg(test)]
mod tests {
use alloc::vec;
use super::*;
use crate::css::CssRuleBlock;
fn sample_css() -> Css {
let path = CssPath::new(vec![CssPathSelector::Type(NodeTypeTag::Div)]);
let block = CssRuleBlock::new(path, vec![]);
Css {
rules: vec![block].into(),
#[test]
fn rust_backend_emits_const_literal() {
let css = sample_css();
let rust = RustBackend.emit_css(&css);
assert!(rust.contains("const CSS: Css"));
assert!(rust.contains("NodeTypeTag::Div"));
fn rust_backend_emits_project_files() {
let files = RustBackend.emit_project(&css);
let paths: alloc::vec::Vec<_> = files.iter().map(|f| f.path.as_str()).collect();
assert!(paths.contains(&"Cargo.toml"));
assert!(paths.contains(&"src/main.rs"));
let main_rs = files
.find(|f| f.path == "src/main.rs")
.expect("main.rs missing");
assert!(main_rs.contains_const_literal());
impl GeneratedFile {
fn contains_const_literal(&self) -> bool {
self.contents.contains("const CSS: Css")