use proc_macro2::Delimiter;
use quote::{quote, quote_spanned, ToTokens};
use syn::buffer::Cursor;
use syn::parse::{Parse, ParseStream};
use syn::{braced, token};
use super::{HtmlIterable, HtmlNode, ToNodeIterator};
use crate::PeekValue;
pub struct HtmlBlock {
pub content: BlockContent,
brace: token::Brace,
}
pub enum BlockContent {
Node(Box<HtmlNode>),
Iterable(Box<HtmlIterable>),
}
impl PeekValue<()> for HtmlBlock {
fn peek(cursor: Cursor) -> Option<()> {
cursor.group(Delimiter::Brace).map(|_| ())
}
}
impl Parse for HtmlBlock {
fn parse(input: ParseStream) -> syn::Result<Self> {
let content;
let brace = braced!(content in input);
let content = if HtmlIterable::peek(content.cursor()).is_some() {
BlockContent::Iterable(Box::new(content.parse()?))
} else {
BlockContent::Node(Box::new(content.parse()?))
};
Ok(HtmlBlock { content, brace })
}
}
impl ToTokens for HtmlBlock {
fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
let HtmlBlock { content, .. } = self;
let new_tokens = match content {
BlockContent::Iterable(html_iterable) => quote! {#html_iterable},
BlockContent::Node(html_node) => quote! {#html_node},
};
tokens.extend(quote! {#new_tokens});
}
}
impl ToNodeIterator for HtmlBlock {
fn to_node_iterator_stream(&self) -> Option<proc_macro2::TokenStream> {
let HtmlBlock { content, brace } = self;
let new_tokens = match content {
BlockContent::Iterable(iterable) => iterable.to_node_iterator_stream(),
BlockContent::Node(node) => node.to_node_iterator_stream(),
}?;
Some(quote_spanned! {brace.span=> #new_tokens})
}
}