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feat: support full attribute syntax on components #220

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278 changes: 198 additions & 80 deletions crates/hypertext-macros/src/html/component.rs
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Original file line number Diff line number Diff line change
@@ -1,13 +1,17 @@
use proc_macro2::TokenStream;
use quote::{ToTokens, quote};
use proc_macro2::{Span, TokenStream};
use quote::{ToTokens, format_ident, quote};
use syn::{
Ident, Lit, Token,
Ident, LitStr,
parse::{Parse, ParseStream},
spanned::Spanned,
token::{Brace, Paren},
};

use super::{AttributeValue, ElementBody, Generate, Generator, ParenExpr, Syntax};
use crate::html::Node;
use super::{
Attribute, AttributeKind, AttributeValue, Class, ElementBody, Generate, Generator, Syntax,
generate::AnyBlock,
};
use crate::html::{Node, basics::Literal};

pub struct Component<S: Syntax> {
pub name: Ident,
Expand All @@ -19,27 +23,16 @@ impl<S: Syntax> Generate for Component<S> {
type Context = Node<S>;

fn generate(&self, g: &mut Generator) {
let props = self.attrs.iter().map(|attr| {
let name = &attr.name;
attr.value_expr()
.map_or_else(|| quote!(.#name(#name)), |value| quote!(.#name(#value)))
});
let mut owned: Vec<TokenStream> = vec![];
let props: Vec<TokenStream> = self
.attrs
.iter()
.map(|attr| attr.kind_expr(g, &mut owned))
.collect();

let children = match &self.body {
ElementBody::Normal { children, .. } => {
let buffer_ident = Generator::buffer_ident();

let block = g.block_with(Brace::default(), |g| {
g.push(children);
});

let lazy = quote! {
::hypertext::Lazy::dangerously_create(
|#buffer_ident: &mut ::hypertext::Buffer|
#block
)
};

let lazy = lazy_block(&children.block(g, Brace::default()));
let children_ident = Ident::new("children", self.name.span());

quote!(
Expand All @@ -51,80 +44,205 @@ impl<S: Syntax> Generate for Component<S> {

let name = &self.name;

let init = quote! {
#name::builder()
#(#props)*
#children
.build()
};

g.push_expr::<Self::Context>(Paren::default(), &init);
g.push_in_block(Brace::default(), |g| {
g.push_stmt(quote! { #(#owned)* });
g.push_expr::<Self::Context>(
Paren::default(),
quote! {
#name::builder()
#(#props)*
#children
.build()
},
);
});
}
}

pub struct ComponentAttribute {
name: Ident,
value: Option<ComponentAttributeValue>,
fn lazy_block(block: &AnyBlock) -> TokenStream {
let buffer_ident = Generator::buffer_ident();
quote! {
::hypertext::Lazy::dangerously_create(
|#buffer_ident: &mut ::hypertext::Buffer|
#block
)
}
}

pub struct ComponentAttribute(pub Attribute);

impl ComponentAttribute {
fn value_expr(&self) -> Option<TokenStream> {
self.value.as_ref().map(|value| match value {
ComponentAttributeValue::Literal(lit) => lit.to_token_stream(),
ComponentAttributeValue::Ident(ident) => ident.to_token_stream(),
ComponentAttributeValue::Expr(expr) => {
let mut tokens = TokenStream::new();

expr.paren_token.surround(&mut tokens, |tokens| {
expr.expr.to_tokens(tokens);
});
fn kind_expr(&self, g: &mut Generator, owned: &mut Vec<TokenStream>) -> TokenStream {
let lits = self.0.name.lits();
let name_str = lits.iter().map(syn::LitStr::value).collect::<String>();
let span = lits.first().map_or_else(Span::call_site, Spanned::span);
let name = Ident::new(&name_str, span);
let maybe_name = format_ident!("maybe_{name}", span = span);
match &self.0.kind {
AttributeKind::Value { value, toggle } => {
let value_expr = Self::value_expr(value, g, owned);
toggle.as_ref().map_or_else(
|| quote!(.#name(#value_expr)),
|toggle| {
let toggle_expr = &toggle.expr;
quote!(.#maybe_name(if #toggle_expr { Some(#value_expr) } else { None }))
},
)
}
AttributeKind::Option(toggle) => {
let toggle_expr = &toggle.expr;
quote!(.#maybe_name(#toggle_expr))
}
AttributeKind::Empty(None) => {
quote!(.#name(true))
}
AttributeKind::Empty(Some(toggle)) => {
let toggle_expr = &toggle.expr;
quote!(.#maybe_name(if #toggle_expr { Some(true) } else { None }))
}
AttributeKind::ClassList(classes) => {
let to_litstr = |class: &Class| {
let Class::Value {
value,
toggle: None,
} = class
else {
return None;
};

let AttributeValue::Literal(literal) = value else {
return None;
};

Some(literal.lit_str())
};

quote! {
{
#[allow(unused_parens)]
#tokens
let to_class = |static_str: &str| {
let literal = Literal::Str(LitStr::new(static_str, span));
Class::Value {
value: AttributeValue::Literal(literal),
toggle: None,
}
};

let mut current_static: String = String::new();
let mut class_exprs: Vec<TokenStream> = vec![];

// Collect consecutive static classes into a single string
for class in classes {
if let Some(stat) = to_litstr(class) {
if !current_static.is_empty() {
current_static.push(' ');
}
current_static.push_str(&stat.value());
} else {
let static_class = to_class(&current_static);
class_exprs.push(Self::class_expr(&static_class, g, owned));
class_exprs.push(Self::class_expr(class, g, owned));
current_static.clear();
}
}

// If no expressions were pushed, the whole class expression is just a literal:
if class_exprs.is_empty() {
let literal_class = Literal::Str(LitStr::new(&current_static, span));
quote!(.class(#literal_class))
} else {
if !current_static.is_empty() {
let static_class = to_class(&current_static);
class_exprs.push(Self::class_expr(&static_class, g, owned));
}

let ident = Self::push_owned(
owned,
&quote! {
[#(#class_exprs),*]
.into_iter()
.flatten()
.fold(String::new(), |mut classes, class| {
if !classes.is_empty() { classes.push(' '); }
classes.push_str(class);
classes
});
},
span,
);

quote!(.class(&#ident))
}
}
})
}
}
}

impl Parse for ComponentAttribute {
fn parse(input: ParseStream) -> syn::Result<Self> {
Ok(Self {
name: input.parse()?,
value: {
if input.peek(Token![=]) {
input.parse::<Token![=]>()?;
fn value_expr(
value: &AttributeValue,
g: &mut Generator,
owned: &mut Vec<TokenStream>,
) -> TokenStream {
match value {
AttributeValue::Literal(literal) => literal.into_token_stream(),
AttributeValue::Group(group) => {
let block = g.block_with(Brace::default(), |g| g.push_all(&group.0.0));
let lazy = lazy_block(&block);
let ident =
Self::push_owned(owned, &quote! { #lazy.render().into_inner() }, block.span());
quote!(&(#ident))
}
AttributeValue::Control(control) => {
let block = g.block_with(Brace::default(), |g| {
g.push(control);
});
quote! { #block }
}
AttributeValue::Expr(paren_expr) => {
let expr_tokens = paren_expr.to_token_stream();
quote!(#[allow(unused_parens)] #expr_tokens)
}
AttributeValue::DisplayExpr(expr) => {
let expr_tokens = expr.wrapped_expr();
quote! { #expr_tokens }
}
AttributeValue::DebugExpr(expr) => {
let expr_tokens = expr.wrapped_expr();
quote! { #expr_tokens }
}
AttributeValue::Ident(ident) => quote! { #ident },
}
}

Some(input.parse()?)
} else {
None
}
},
})
fn class_expr(class: &Class, g: &mut Generator, owned: &mut Vec<TokenStream>) -> TokenStream {
match class {
Class::Value {
value,
toggle: None,
} => {
let value_expr = Self::value_expr(value, g, owned);
quote! { Some(#value_expr) }
}
Class::Value {
value,
toggle: Some(toggle),
} => {
let value_expr = Self::value_expr(value, g, owned);
let toggle_expr = &toggle.expr;
quote! { if #toggle_expr { Some(#value_expr) } else { None } }
}
Class::Option(toggle) => {
let toggle_expr = &toggle.expr;
quote! { #toggle_expr }
}
}
}
}

pub enum ComponentAttributeValue {
Literal(Lit),
Ident(Ident),
Expr(ParenExpr<AttributeValue>),
fn push_owned(alloc: &mut Vec<TokenStream>, expr: &TokenStream, span: Span) -> Ident {
let ident = format_ident!("owned_{}", alloc.len(), span = span);
alloc.push(quote!(let #ident = #expr;));
ident
}
}

impl Parse for ComponentAttributeValue {
impl Parse for ComponentAttribute {
fn parse(input: ParseStream) -> syn::Result<Self> {
let lookahead = input.lookahead1();

if lookahead.peek(Lit) {
input.parse().map(Self::Literal)
} else if lookahead.peek(Ident) {
input.parse().map(Self::Ident)
} else if lookahead.peek(Paren) {
input.parse().map(Self::Expr)
} else {
Err(lookahead.error())
}
Ok(Self(input.parse()?))
}
}
23 changes: 10 additions & 13 deletions crates/hypertext-macros/src/html/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -471,12 +471,12 @@ pub struct Attribute {
impl Attribute {
fn parse_id(input: ParseStream) -> syn::Result<Self> {
let pound_token = input.parse::<Token![#]>()?;
let name = parse_quote_spanned!(pound_token.span()=> id);
let value = input.call(AttributeValue::parse_unquoted)?;
let toggle = input.call(Toggle::parse_optional)?;
Ok(Self {
name: parse_quote_spanned!(pound_token.span()=> id),
kind: AttributeKind::Value {
value: input.call(AttributeValue::parse_unquoted)?,
toggle: None,
},
name,
kind: AttributeKind::Value { value, toggle },
})
}

Expand Down Expand Up @@ -781,14 +781,11 @@ pub enum AttributeValue {
impl AttributeValue {
fn parse_unquoted(input: ParseStream) -> syn::Result<Self> {
if input.peek(Ident::peek_any) || input.peek(LitInt) {
Ok(Self::Group(Group(Many(
input
.call(UnquotedName::parse_attr_value)?
.lits()
.into_iter()
.map(|lit| Self::Literal(Literal::Str(lit)))
.collect(),
))))
let lits = UnquotedName::parse_attr_value(input)?.lits();
let span = lits.first().map_or_else(Span::call_site, LitStr::span);
let name = lits.into_iter().map(|lit| lit.value()).collect::<String>();

Ok(Self::Literal(Literal::Str(LitStr::new(&name, span))))
} else {
input.parse()
}
Expand Down
14 changes: 13 additions & 1 deletion crates/hypertext-macros/src/html/syntaxes/maud.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@ use syn::{

use crate::html::{
Attribute, Component, Doctype, Element, ElementBody, Group, Node, Syntax, UnquotedName,
XmlDecl, kw,
XmlDecl, component::ComponentAttribute, kw,
};

pub struct Maud;
Expand Down Expand Up @@ -149,6 +149,18 @@ impl Parse for Component<Maud> {
attrs: {
let mut attrs = Vec::new();

if input.peek(Token![#]) {
attrs.push(input.call(Attribute::parse_id).map(ComponentAttribute)?);
}

if input.peek(Token![.]) {
attrs.push(
input
.call(Attribute::parse_class_list)
.map(ComponentAttribute)?,
);
}

while !(input.peek(Token![..]) || input.peek(Token![;]) || input.peek(Brace)) {
attrs.push(input.parse()?);
}
Expand Down
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