Introduce proc macros for scraper

.gitignore

@@ -1,3 +1,4 @@
 target
 *.bk
 .idea
+.vscode

Cargo.toml

@@ -1,4 +1,8 @@
 [workspace]
 resolver = "2"
 
-members = ["scraper"]
+members = ["scraper", "scraper_proc_macros"]
+
+[workspace.dependencies]
+scraper = { path = "./scraper" }
+scraper_proc_macros = { path = "./scraper_proc_macros" }

scraper/Cargo.toml

@@ -14,7 +14,7 @@ readme = "README.md"
 
 [dependencies]
 cssparser = "0.31.0"
-ego-tree = "0.8.0"
+ego-tree = "0.9.0"
 html5ever = "0.27"
 selectors = "0.25.0"
 tendril = "0.4.3"

scraper_proc_macros/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "scraper_proc_macros"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "1.0.86"
+quote = "1.0.37"
+scraper = { workspace = true }
+syn = "2.0.76"

scraper_proc_macros/src/lib.rs

@@ -0,0 +1,21 @@
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{parse_macro_input, LitStr};
+
+#[proc_macro]
+pub fn selector(input: TokenStream) -> TokenStream {
+    let selector = parse_macro_input!(input as LitStr);
+
+    match scraper::Selector::parse(&selector.value()) {
+        Ok(_) => quote!(
+            ::scraper::Selector::parse(#selector).unwrap()
+        )
+        .into(),
+        Err(e) => syn::Error::new(
+            proc_macro2::Span::call_site(),
+            format!("Failed to parse CSS selector: {}", e),
+        )
+        .to_compile_error()
+        .into(),
+    }
+}