skhtml/macros/src/html.rs

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use proc_macro::{Diagnostic, Level};
use proc_macro2::{Delimiter, Group, Ident, Literal, TokenStream, TokenTree};
use quote::quote;
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use config::{required_children, ATTR_EVENTS};
use error::ParseError;
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use ident;
use lexer::{Lexer, Token};
use map::StringyMap;
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use parser::grammar;
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use std::iter::FromIterator;
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#[derive(Clone)]
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pub enum Node {
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Element(Element),
Text(Literal),
Block(Group),
}
impl Node {
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pub fn into_token_stream(self) -> TokenStream {
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match self {
Node::Element(el) => el.into_token_stream(),
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Node::Text(text) => {
let text = TokenTree::Literal(text);
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quote!(Box::new(typed_html::dom::TextNode::new(#text.to_string())))
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}
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Node::Block(_) => panic!("cannot have a block in this position"),
}
}
fn into_child_stream(self) -> TokenStream {
match self {
Node::Element(el) => {
let el = el.into_token_stream();
quote!(
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element.children.push(#el);
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)
}
tx @ Node::Text(_) => {
let tx = tx.into_token_stream();
quote!(
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element.children.push(#tx);
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)
}
Node::Block(group) => {
let group: TokenTree = group.into();
quote!(
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for child in #group.into_iter() {
element.children.push(child);
}
)
}
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}
}
}
#[derive(Clone)]
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pub struct Element {
pub name: Ident,
pub attributes: StringyMap<Ident, TokenTree>,
pub children: Vec<Node>,
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}
fn extract_data_attrs(attrs: &mut StringyMap<Ident, TokenTree>) -> StringyMap<String, TokenTree> {
let mut data = StringyMap::new();
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let keys: Vec<Ident> = attrs.keys().cloned().collect();
for key in keys {
let key_name = key.to_string();
let prefix = "data_";
if key_name.starts_with(prefix) {
let value = attrs.remove(&key).unwrap();
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data.insert(format!("data-{}", &key_name[prefix.len()..]), value);
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}
}
data
}
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fn extract_event_handlers(
attrs: &mut StringyMap<Ident, TokenTree>,
) -> StringyMap<Ident, TokenTree> {
let mut events = StringyMap::new();
let keys: Vec<Ident> = attrs.keys().cloned().collect();
for key in keys {
let key_name = key.to_string();
let prefix = "on";
if key_name.starts_with(prefix) {
let event_name = &key_name[prefix.len()..];
if ATTR_EVENTS.binary_search(&event_name).is_ok() {
let value = attrs.remove(&key).unwrap();
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events.insert(ident::new_raw(event_name, key.span()), value);
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}
}
}
events
}
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fn process_value(value: &TokenTree) -> TokenStream {
match value {
TokenTree::Group(g) if g.delimiter() == Delimiter::Bracket => {
let content = g.stream();
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quote!( [ #content ] )
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}
TokenTree::Group(g) if g.delimiter() == Delimiter::Parenthesis => {
let content = g.stream();
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quote!( ( #content ) )
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}
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v => TokenStream::from_iter(vec![v.clone()]),
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}
}
fn is_string_literal(literal: &Literal) -> bool {
// This is the worst API
literal.to_string().starts_with('"')
}
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impl Element {
fn into_token_stream(mut self) -> TokenStream {
let name = self.name;
let name_str = name.to_string();
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let typename: TokenTree = Ident::new(&name_str, name.span()).into();
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let req_names = required_children(&name_str);
if req_names.len() > self.children.len() {
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Diagnostic::spanned(
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name.span().unstable(),
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Level::Error,
format!(
"<{}> requires {} children but there are only {}",
name_str,
req_names.len(),
self.children.len()
),
)
.emit();
panic!();
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}
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let events = extract_event_handlers(&mut self.attributes);
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let data_attrs = extract_data_attrs(&mut self.attributes);
let attrs = self.attributes.iter().map(|(key, value)| {
(
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key.to_string(),
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TokenTree::Ident(ident::new_raw(&key.to_string(), key.span())),
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value,
)
});
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let opt_children = self
.children
.split_off(req_names.len())
.into_iter()
.map(Node::into_child_stream);
let req_children = self.children.into_iter().map(Node::into_token_stream);
let mut body = TokenStream::new();
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for (attr_str, key, value) in attrs {
match value {
TokenTree::Literal(l) if is_string_literal(l) => {
let value = value.clone();
let tag_name: TokenTree = Literal::string(&name_str).into();
let attr_str: TokenTree = Literal::string(&attr_str).into();
let span = value.span();
let pos = format!(
"{}:{}:{}",
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span.unstable().source_file().path().to_str().unwrap_or("unknown"),
span.unstable().start().line,
span.unstable().start().column
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);
let pos_str: TokenTree = Literal::string(&pos).into();
body.extend(quote!(
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element.attrs.#key = Some(#value.parse().unwrap_or_else(|err| {
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eprintln!("ERROR: {}: <{} {}={:?}> failed to parse attribute value: {}",
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#pos_str, #tag_name, #attr_str, #value, err);
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panic!("failed to parse string literal");
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}));
));
}
value => {
let value = process_value(value);
body.extend(quote!(
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element.attrs.#key = Some(std::convert::Into::into(#value));
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));
}
}
}
for (key, value) in data_attrs
.iter()
.map(|(k, v)| (TokenTree::from(Literal::string(&k)), v.clone()))
{
body.extend(quote!(
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element.data_attributes.push((#key, #value.into()));
));
}
body.extend(opt_children);
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for (key, value) in events.iter() {
let key = TokenTree::Ident(key.clone());
let value = process_value(value);
body.extend(quote!(
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element.events.#key = Some(typed_html::events::IntoEventHandler::into_event_handler(#value));
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));
}
let mut args = TokenStream::new();
for arg in req_children {
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args.extend(quote!( #arg, ));
}
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quote!(
{
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let mut element = typed_html::elements::#typename::new(#args);
#body
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Box::new(element)
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}
)
}
}
// FIXME report a decent error when the macro contains multiple top level elements
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pub fn expand_html(input: &[Token]) -> Result<Node, ParseError> {
grammar::NodeParser::new().parse(Lexer::new(input))
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}