Add top level sections to the Unstable Book.

Prior to this commit, the contents of the Unstable Book were assumed to
be unstable features. This commit moves features into 'language features'
or 'library features' subsections. It also moves the 'linker_flavor'
compiler flag into a new 'Compiler Flags' subsection.

Even though it was helpful, I removed the tidy check that
cross-references the SUMMARY.md links with the Unstable Book directory
contents just because it would be difficult to maintain.

Relevant PR: rust-lang#41142.

src/doc/guide-plugins.md

@@ -1,4 +1,4 @@
 % The (old) Rust Compiler Plugins Guide
 
 This content has moved into
-[the Unstable Book](unstable-book/plugin.html).
+[the Unstable Book](unstable-book/language-features/plugin.html).

src/doc/unstable-book/src/compiler-flags.md

@@ -0,0 +1 @@
+# Compiler flags

src/doc/unstable-book/src/language-features.md

@@ -0,0 +1 @@
+# Language features

src/doc/unstable-book/src/library-features.md

@@ -0,0 +1 @@
+# Library Features

src/doc/unstable-book/src/the-unstable-book.md

@@ -14,7 +14,7 @@ fn main() {
 
 The `box_syntax` feature [has a chapter][box] describing how to use it.
 
-[box]: box-syntax.html
+[box]: language-features/box-syntax.html
 
 Because this documentation relates to unstable features, we make no guarantees
 that what is contained here is accurate or up to date. It's developed on a

src/libsyntax/feature_gate.rs

@@ -344,9 +344,6 @@ declare_features! (
     // Used to preserve symbols (see llvm.used)
     (active, used, "1.18.0", Some(40289)),
 
-    // Hack to document `-Z linker-flavor` in The Unstable Book
-    (active, linker_flavor, "1.18.0", Some(41142)),
-
     // Allows module-level inline assembly by way of global_asm!()
     (active, global_asm, "1.18.0", Some(35119)),
 

src/tools/linkchecker/main.rs

@@ -147,6 +147,12 @@ fn check(cache: &mut Cache,
         return None;
     }
 
+    // mdbook uses the HTML <base> tag to handle links for subdirectories, which
+    // linkchecker doesn't support
+    if file.to_str().unwrap().contains("unstable-book/") {
+        return None;
+    }
+
     let res = load_file(cache, root, PathBuf::from(file), SkipRedirect);
     let (pretty_file, contents) = match res {
         Ok(res) => res,

src/tools/tidy/Cargo.toml

@@ -2,6 +2,3 @@
 name = "tidy"
 version = "0.1.0"
 authors = ["Alex Crichton <[email protected]>"]
-
-[dependencies]
-regex = "0.2"

src/tools/tidy/src/main.rs

@@ -14,8 +14,6 @@
 //! etc. This is run by default on `make check` and as part of the auto
 //! builders.
 
-extern crate regex;
-
 use std::env;
 use std::fs;
 use std::io::{self, Write};

src/tools/tidy/src/unstable_book.rs

@@ -10,35 +10,36 @@
 
 use std::collections::HashSet;
 use std::fs;
-use std::io::{self, BufRead};
 use std::path;
 use features::{collect_lang_features, collect_lib_features, Status};
 
 const PATH_STR: &'static str = "doc/unstable-book/src";
 
-const SUMMARY_FILE_NAME: &'static str = "SUMMARY.md";
+const LANG_FEATURES_DIR: &'static str = "language-features";
 
-static EXCLUDE: &'static [&'static str; 2] = &[SUMMARY_FILE_NAME, "the-unstable-book.md"];
+const LIB_FEATURES_DIR: &'static str = "library-features";
 
 /// Build the path to the Unstable Book source directory from the Rust 'src' directory
 fn unstable_book_path(base_src_path: &path::Path) -> path::PathBuf {
     base_src_path.join(PATH_STR)
 }
 
-/// Build the path to the Unstable Book SUMMARY file from the Rust 'src' directory
-fn unstable_book_summary_path(base_src_path: &path::Path) -> path::PathBuf {
-    unstable_book_path(base_src_path).join(SUMMARY_FILE_NAME)
+/// Directory where the features are documented within the Unstable Book source directory
+fn unstable_book_lang_features_path(base_src_path: &path::Path) -> path::PathBuf {
+    unstable_book_path(base_src_path).join(LANG_FEATURES_DIR)
 }
 
-/// Open the Unstable Book SUMMARY file
-fn open_unstable_book_summary_file(base_src_path: &path::Path) -> fs::File {
-    fs::File::open(unstable_book_summary_path(base_src_path))
-        .expect("could not open Unstable Book SUMMARY.md")
+/// Directory where the features are documented within the Unstable Book source directory
+fn unstable_book_lib_features_path(base_src_path: &path::Path) -> path::PathBuf {
+    unstable_book_path(base_src_path).join(LIB_FEATURES_DIR)
 }
 
 /// Test to determine if DirEntry is a file
 fn dir_entry_is_file(dir_entry: &fs::DirEntry) -> bool {
-    dir_entry.file_type().expect("could not determine file type of directory entry").is_file()
+    dir_entry
+        .file_type()
+        .expect("could not determine file type of directory entry")
+        .is_file()
 }
 
 /// Retrieve names of all lang-related unstable features
@@ -61,75 +62,81 @@ fn collect_unstable_lib_feature_names(base_src_path: &path::Path) -> HashSet<Str
         .collect()
 }
 
-/// Retrieve names of all unstable features
-fn collect_unstable_feature_names(base_src_path: &path::Path) -> HashSet<String> {
-    collect_unstable_lib_feature_names(base_src_path)
-        .union(&collect_unstable_lang_feature_names(base_src_path))
-        .map(|n| n.to_owned())
-        .collect::<HashSet<_, _>>()
-}
-
-/// Retrieve file names of all sections in the Unstable Book with:
-///
-/// * hyphens replaced by underscores
-/// * the markdown suffix ('.md') removed
-fn collect_unstable_book_section_file_names(base_src_path: &path::Path) -> HashSet<String> {
-    fs::read_dir(unstable_book_path(base_src_path))
+fn collect_unstable_book_section_file_names(dir: &path::Path) -> HashSet<String> {
+    fs::read_dir(dir)
         .expect("could not read directory")
         .into_iter()
         .map(|entry| entry.expect("could not read directory entry"))
         .filter(dir_entry_is_file)
         .map(|entry| entry.file_name().into_string().unwrap())
-        .filter(|n| EXCLUDE.iter().all(|e| n != e))
         .map(|n| n.trim_right_matches(".md").replace('-', "_"))
         .collect()
 }
 
-/// Retrieve unstable feature names that are in the Unstable Book SUMMARY file
-fn collect_unstable_book_summary_links(base_src_path: &path::Path) -> HashSet<String> {
-    let summary_link_regex =
-        ::regex::Regex::new(r"^- \[(\S+)\]\(\S+\.md\)").expect("invalid regex");
-    io::BufReader::new(open_unstable_book_summary_file(base_src_path))
-        .lines()
-        .map(|l| l.expect("could not read line from file"))
-        .filter_map(|line| {
-            summary_link_regex.captures(&line).map(|c| {
-                                                       c.get(1)
-                                                           .unwrap()
-                                                           .as_str()
-                                                           .to_owned()
-                                                   })
-        })
-        .collect()
+/// Retrieve file names of all library feature sections in the Unstable Book with:
+///
+/// * hyphens replaced by underscores
+/// * the markdown suffix ('.md') removed
+fn collect_unstable_book_lang_features_section_file_names(base_src_path: &path::Path)
+                                                          -> HashSet<String> {
+    collect_unstable_book_section_file_names(&unstable_book_lang_features_path(base_src_path))
+}
+
+/// Retrieve file names of all language feature sections in the Unstable Book with:
+///
+/// * hyphens replaced by underscores
+/// * the markdown suffix ('.md') removed
+fn collect_unstable_book_lib_features_section_file_names(base_src_path: &path::Path)
+                                                         -> HashSet<String> {
+    collect_unstable_book_section_file_names(&unstable_book_lib_features_path(base_src_path))
 }
 
 pub fn check(path: &path::Path, bad: &mut bool) {
-    let unstable_feature_names = collect_unstable_feature_names(path);
-    let unstable_book_section_file_names = collect_unstable_book_section_file_names(path);
-    let unstable_book_links = collect_unstable_book_summary_links(path);
-
-    // Check for Unstable Book section names with no corresponding SUMMARY.md link
-    for feature_name in &unstable_book_section_file_names - &unstable_book_links {
-        tidy_error!(
-            bad,
-            "The Unstable Book section '{}' needs to have a link in SUMMARY.md",
-            feature_name);
-    }
+
+    // Library features
+
+    let unstable_lib_feature_names = collect_unstable_lib_feature_names(path);
+    let unstable_book_lib_features_section_file_names =
+        collect_unstable_book_lib_features_section_file_names(path);
 
     // Check for unstable features that don't have Unstable Book sections
-    for feature_name in &unstable_feature_names - &unstable_book_section_file_names {
-        tidy_error!(
-            bad,
-            "Unstable feature '{}' needs to have a section in The Unstable Book",
-            feature_name);
+    for feature_name in &unstable_lib_feature_names -
+                        &unstable_book_lib_features_section_file_names {
+        tidy_error!(bad,
+                    "Unstable library feature '{}' needs to have a section within the \
+                     'library features' section of The Unstable Book",
+                    feature_name);
+    }
+
+    // Check for Unstable Book sections that don't have a corresponding unstable feature
+    for feature_name in &unstable_book_lib_features_section_file_names -
+                        &unstable_lib_feature_names {
+        tidy_error!(bad,
+                    "The Unstable Book has a 'library feature' section '{}' which doesn't \
+                     correspond to an unstable library feature",
+                    feature_name)
+    }
+
+    // Language features
+
+    let unstable_lang_feature_names = collect_unstable_lang_feature_names(path);
+    let unstable_book_lang_features_section_file_names =
+        collect_unstable_book_lang_features_section_file_names(path);
+
+    for feature_name in &unstable_lang_feature_names -
+                        &unstable_book_lang_features_section_file_names {
+        tidy_error!(bad,
+                    "Unstable language feature '{}' needs to have a section within the \
+                     'language features' section of The Unstable Book",
+                    feature_name);
     }
 
     // Check for Unstable Book sections that don't have a corresponding unstable feature
-    for feature_name in &unstable_book_section_file_names - &unstable_feature_names {
-        tidy_error!(
-            bad,
-            "The Unstable Book has a section '{}' which doesn't correspond \
-            to an unstable feature",
-            feature_name)
+    for feature_name in &unstable_book_lang_features_section_file_names -
+                        &unstable_lang_feature_names {
+        tidy_error!(bad,
+                    "The Unstable Book has a 'language feature' section '{}' which doesn't \
+                     correspond to an unstable language feature",
+                    feature_name)
     }
 }