rust-lang · kpp · Nov 17, 2019 · Nov 17, 2019
diff --git a/book-example/book.toml b/book-example/book.toml
@@ -3,6 +3,7 @@ title = "mdBook Documentation"
 description = "Create book from markdown files. Like Gitbook but implemented in Rust"
 authors = ["Mathieu David", "Michael-F-Bryan"]
 language = "en"
+edition = "2018"
 
 [output.html]
 mathjax-support = true

diff --git a/book-example/src/format/config.md b/book-example/src/format/config.md
@@ -9,6 +9,7 @@ Here is an example of what a ***book.toml*** file might look like:
 title = "Example book"
 author = "John Doe"
 description = "The example book covers examples."
+edition = "2018"
 
 [build]
 build-dir = "my-example-book"
@@ -43,6 +44,7 @@ This is general information about your book.
   `src` directly under the root folder. But this is configurable with the `src`
   key in the configuration file.
 - **language:** The main language of the book, which is used as a language attribute `<html lang="en">` for example.
+- **edition**: Rust edition to use by default for the code snippets. Defaults to `rustdoc` defaults (2015).
 
 **book.toml**
 ```toml
@@ -52,6 +54,7 @@ authors = ["John Doe", "Jane Doe"]
 description = "The example book covers examples."
 src = "my-src"  # the source files will be found in `root/my-src` instead of `root/src`
 language = "en"
+edition = "2018"
 ```
 
 ### Build options
@@ -178,7 +181,7 @@ The following configuration options are available:
   an icon link will be output in the menu bar of the book.
 - **git-repository-icon:** The FontAwesome icon class to use for the git
   repository link. Defaults to `fa-github`.
-  
+
 Available configuration options for the `[output.html.fold]` table:
 
 - **enable:** Enable section-folding. When off, all folds are open.

diff --git a/src/book/mod.rs b/src/book/mod.rs
@@ -27,7 +27,7 @@ use crate::preprocess::{
 use crate::renderer::{CmdRenderer, HtmlHandlebars, MarkdownRenderer, RenderContext, Renderer};
 use crate::utils;
 
-use crate::config::Config;
+use crate::config::{Config, RustEdition};
 
 /// The object used to manage and build a book.
 pub struct MDBook {
@@ -262,11 +262,21 @@ impl MDBook {
                     let mut tmpf = utils::fs::create_file(&path)?;
                     tmpf.write_all(ch.content.as_bytes())?;
 
-                    let output = Command::new("rustdoc")
-                        .arg(&path)
-                        .arg("--test")
-                        .args(&library_args)
-                        .output()?;
+                    let mut cmd = Command::new("rustdoc");
+                    cmd.arg(&path).arg("--test").args(&library_args);
+
+                    if let Some(edition) = self.config.book.edition {
+                        match edition {
+                            RustEdition::E2015 => {
+                                cmd.args(&["--edition", "2015"]);
+                            }
+                            RustEdition::E2018 => {
+                                cmd.args(&["--edition", "2018"]);
+                            }
+                        }
+                    }
+
+                    let output = cmd.output()?;
 
                     if !output.status.success() {
                         bail!(ErrorKind::Subprocess(

diff --git a/src/config.rs b/src/config.rs
@@ -393,6 +393,8 @@ pub struct BookConfig {
     pub multilingual: bool,
     /// The main language of the book.
     pub language: Option<String>,
+    /// Rust edition to use for the code.
+    pub edition: Option<RustEdition>,
 }
 
 impl Default for BookConfig {
@@ -404,10 +406,60 @@ impl Default for BookConfig {
             src: PathBuf::from("src"),
             multilingual: false,
             language: Some(String::from("en")),
+            edition: None,
         }
     }
 }
 
+#[derive(Debug, Copy, Clone, PartialEq)]
+/// Rust edition to use for the code.
+pub enum RustEdition {
+    /// The 2018 edition of Rust
+    E2018,
+    /// The 2015 edition of Rust
+    E2015,
+}
+
+impl Serialize for RustEdition {
+    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        match self {
+            RustEdition::E2015 => serializer.serialize_str("2015"),
+            RustEdition::E2018 => serializer.serialize_str("2018"),
+        }
+    }
+}
+
+impl<'de> Deserialize<'de> for RustEdition {
+    fn deserialize<D>(de: D) -> std::result::Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        use serde::de::Error;
+
+        let raw = Value::deserialize(de)?;
+
+        let edition = match raw {
+            Value::String(s) => s,
+            _ => {
+                return Err(D::Error::custom("Rust edition should be a string"));
+            }
+        };
+
+        let edition = match edition.as_str() {
+            "2018" => RustEdition::E2018,
+            "2015" => RustEdition::E2015,
+            _ => {
+                return Err(D::Error::custom("Unknown Rust edition"));
+            }
+        };
+
+        Ok(edition)
+    }
+}
+
 /// Configuration for the build procedure.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(default, rename_all = "kebab-case")]
@@ -647,6 +699,7 @@ mod tests {
             multilingual: true,
             src: PathBuf::from("source"),
             language: Some(String::from("ja")),
+            edition: None,
         };
         let build_should_be = BuildConfig {
             build_dir: PathBuf::from("outputs"),
@@ -678,6 +731,58 @@ mod tests {
         assert_eq!(got.html_config().unwrap(), html_should_be);
     }
 
+    #[test]
+    fn edition_2015() {
+        let src = r#"
+        [book]
+        title = "mdBook Documentation"
+        description = "Create book from markdown files. Like Gitbook but implemented in Rust"
+        authors = ["Mathieu David"]
+        src = "./source"
+        edition = "2015"
+        "#;
+
+        let book_should_be = BookConfig {
+            title: Some(String::from("mdBook Documentation")),
+            description: Some(String::from(
+                "Create book from markdown files. Like Gitbook but implemented in Rust",
+            )),
+            authors: vec![String::from("Mathieu David")],
+            src: PathBuf::from("./source"),
+            edition: Some(RustEdition::E2015),
+            ..Default::default()
+        };
+
+        let got = Config::from_str(src).unwrap();
+        assert_eq!(got.book, book_should_be);
+    }
+
+    #[test]
+    fn edition_2018() {
+        let src = r#"
+        [book]
+        title = "mdBook Documentation"
+        description = "Create book from markdown files. Like Gitbook but implemented in Rust"
+        authors = ["Mathieu David"]
+        src = "./source"
+        edition = "2018"
+        "#;
+
+        let book_should_be = BookConfig {
+            title: Some(String::from("mdBook Documentation")),
+            description: Some(String::from(
+                "Create book from markdown files. Like Gitbook but implemented in Rust",
+            )),
+            authors: vec![String::from("Mathieu David")],
+            src: PathBuf::from("./source"),
+            edition: Some(RustEdition::E2018),
+            ..Default::default()
+        };
+
+        let got = Config::from_str(src).unwrap();
+        assert_eq!(got.book, book_should_be);
+    }
+
     #[test]
     fn load_arbitrary_output_type() {
         #[derive(Debug, Deserialize, PartialEq)]

diff --git a/src/renderer/html_handlebars/hbs_renderer.rs b/src/renderer/html_handlebars/hbs_renderer.rs
@@ -1,5 +1,5 @@
 use crate::book::{Book, BookItem};
-use crate::config::{Config, HtmlConfig, Playpen};
+use crate::config::{Config, HtmlConfig, Playpen, RustEdition};
 use crate::errors::*;
 use crate::renderer::html_handlebars::helpers;
 use crate::renderer::{RenderContext, Renderer};
@@ -81,7 +81,7 @@ impl HtmlHandlebars {
             debug!("Render template");
             let rendered = ctx.handlebars.render("index", &ctx.data)?;
 
-            let rendered = self.post_process(rendered, &ctx.html_config.playpen);
+            let rendered = self.post_process(rendered, &ctx.html_config.playpen, ctx.edition);
 
             // Write to file
             debug!("Creating {}", filepath.display());
@@ -92,7 +92,8 @@ impl HtmlHandlebars {
                 ctx.data.insert("path_to_root".to_owned(), json!(""));
                 ctx.data.insert("is_index".to_owned(), json!("true"));
                 let rendered_index = ctx.handlebars.render("index", &ctx.data)?;
-                let rendered_index = self.post_process(rendered_index, &ctx.html_config.playpen);
+                let rendered_index =
+                    self.post_process(rendered_index, &ctx.html_config.playpen, ctx.edition);
                 debug!("Creating index.html from {}", path);
                 utils::fs::write_file(&ctx.destination, "index.html", rendered_index.as_bytes())?;
             }
@@ -102,10 +103,15 @@ impl HtmlHandlebars {
     }
 
     #[cfg_attr(feature = "cargo-clippy", allow(clippy::let_and_return))]
-    fn post_process(&self, rendered: String, playpen_config: &Playpen) -> String {
+    fn post_process(
+        &self,
+        rendered: String,
+        playpen_config: &Playpen,
+        edition: Option<RustEdition>,
+    ) -> String {
         let rendered = build_header_links(&rendered);
         let rendered = fix_code_blocks(&rendered);
-        let rendered = add_playpen_pre(&rendered, playpen_config);
+        let rendered = add_playpen_pre(&rendered, playpen_config, edition);
 
         rendered
     }
@@ -338,6 +344,7 @@ impl Renderer for HtmlHandlebars {
                 data: data.clone(),
                 is_index,
                 html_config: html_config.clone(),
+                edition: ctx.config.book.edition,
             };
             self.render_item(item, ctx, &mut print_content)?;
             is_index = false;
@@ -353,7 +360,7 @@ impl Renderer for HtmlHandlebars {
         debug!("Render template");
         let rendered = handlebars.render("index", &data)?;
 
-        let rendered = self.post_process(rendered, &html_config.playpen);
+        let rendered = self.post_process(rendered, &html_config.playpen, ctx.config.book.edition);
 
         utils::fs::write_file(&destination, "print.html", rendered.as_bytes())?;
         debug!("Creating print.html ✓");
@@ -600,7 +607,7 @@ fn fix_code_blocks(html: &str) -> String {
         .into_owned()
 }
 
-fn add_playpen_pre(html: &str, playpen_config: &Playpen) -> String {
+fn add_playpen_pre(html: &str, playpen_config: &Playpen, edition: Option<RustEdition>) -> String {
     let regex = Regex::new(r##"((?s)<code[^>]?class="([^"]+)".*?>(.*?)</code>)"##).unwrap();
     regex
         .replace_all(html, |caps: &Captures<'_>| {
@@ -612,10 +619,24 @@ fn add_playpen_pre(html: &str, playpen_config: &Playpen) -> String {
                 if (!classes.contains("ignore") && !classes.contains("noplaypen"))
                     || classes.contains("mdbook-runnable")
                 {
+                    let contains_e2015 = classes.contains("edition2015");
+                    let contains_e2018 = classes.contains("edition2018");
+                    let edition_class = if contains_e2015 || contains_e2018 {
+                        // the user forced edition, we should not overwrite it
+                        ""
+                    } else {
+                        match edition {
+                            Some(RustEdition::E2015) => " edition2015",
+                            Some(RustEdition::E2018) => " edition2018",
+                            None => "",
+                        }
+                    };
+
                     // wrap the contents in an external pre block
                     format!(
-                        "<pre class=\"playpen\"><code class=\"{}\">{}</code></pre>",
+                        "<pre class=\"playpen\"><code class=\"{}{}\">{}</code></pre>",
                         classes,
+                        edition_class,
                         {
                             let content: Cow<'_, str> = if playpen_config.editable
                                 && classes.contains("editable")
@@ -706,6 +727,7 @@ struct RenderItemContext<'a> {
     data: serde_json::Map<String, serde_json::Value>,
     is_index: bool,
     html_config: HtmlConfig,
+    edition: Option<RustEdition>,
 }
 
 #[cfg(test)]
@@ -772,6 +794,55 @@ mod tests {
                     editable: true,
                     ..Playpen::default()
                 },
+                None,
+            );
+            assert_eq!(&*got, *should_be);
+        }
+    }
+    #[test]
+    fn add_playpen_edition2015() {
+        let inputs = [
+          ("<code class=\"language-rust\">x()</code>",
+           "<pre class=\"playpen\"><code class=\"language-rust edition2015\">\n<span class=\"boring\">#![allow(unused_variables)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}\n</span></code></pre>"),
+          ("<code class=\"language-rust\">fn main() {}</code>",
+           "<pre class=\"playpen\"><code class=\"language-rust edition2015\">fn main() {}\n</code></pre>"),
+          ("<code class=\"language-rust edition2015\">fn main() {}</code>",
+           "<pre class=\"playpen\"><code class=\"language-rust edition2015\">fn main() {}\n</code></pre>"),
+          ("<code class=\"language-rust edition2018\">fn main() {}</code>",
+           "<pre class=\"playpen\"><code class=\"language-rust edition2018\">fn main() {}\n</code></pre>"),
+        ];
+        for (src, should_be) in &inputs {
+            let got = add_playpen_pre(
+                src,
+                &Playpen {
+                    editable: true,
+                    ..Playpen::default()
+                },
+                Some(RustEdition::E2015),
+            );
+            assert_eq!(&*got, *should_be);
+        }
+    }
+    #[test]
+    fn add_playpen_edition2018() {
+        let inputs = [
+          ("<code class=\"language-rust\">x()</code>",
+           "<pre class=\"playpen\"><code class=\"language-rust edition2018\">\n<span class=\"boring\">#![allow(unused_variables)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}\n</span></code></pre>"),
+          ("<code class=\"language-rust\">fn main() {}</code>",
+           "<pre class=\"playpen\"><code class=\"language-rust edition2018\">fn main() {}\n</code></pre>"),
+          ("<code class=\"language-rust edition2015\">fn main() {}</code>",
+           "<pre class=\"playpen\"><code class=\"language-rust edition2015\">fn main() {}\n</code></pre>"),
+          ("<code class=\"language-rust edition2018\">fn main() {}</code>",
+           "<pre class=\"playpen\"><code class=\"language-rust edition2018\">fn main() {}\n</code></pre>"),
+        ];
+        for (src, should_be) in &inputs {
+            let got = add_playpen_pre(
+                src,
+                &Playpen {
+                    editable: true,
+                    ..Playpen::default()
+                },
+                Some(RustEdition::E2018),
             );
             assert_eq!(&*got, *should_be);
         }