Move rules handling to its own module

There should otherwise be no code changes here.

Author: ehuss

mdbook-spec/src/lib.rs

@@ -11,11 +11,9 @@ use std::collections::BTreeMap;
 use std::io;
 use std::path::PathBuf;
 
+mod rules;
 mod std_links;
 
-/// The Regex for rules like `r[foo]`.
-static RULE_RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"(?m)^r\[([^]]+)]$").unwrap());
-
 /// The Regex for the syntax for blockquotes that have a specific CSS class,
 /// like `> [!WARNING]`.
 static ADMONITION_RE: Lazy<Regex> = Lazy::new(|| {
@@ -57,41 +55,6 @@ impl Spec {
         }
     }
 
-    /// Converts lines that start with `r[…]` into a "rule" which has special
-    /// styling and can be linked to.
-    fn rule_definitions(
-        &self,
-        chapter: &Chapter,
-        found_rules: &mut BTreeMap<String, (PathBuf, PathBuf)>,
-    ) -> String {
-        let source_path = chapter.source_path.clone().unwrap_or_default();
-        let path = chapter.path.clone().unwrap_or_default();
-        RULE_RE
-            .replace_all(&chapter.content, |caps: &Captures<'_>| {
-                let rule_id = &caps[1];
-                if let Some((old, _)) =
-                    found_rules.insert(rule_id.to_string(), (source_path.clone(), path.clone()))
-                {
-                    let message = format!(
-                        "rule `{rule_id}` defined multiple times\n\
-                        First location: {old:?}\n\
-                        Second location: {source_path:?}"
-                    );
-                    if self.deny_warnings {
-                        panic!("error: {message}");
-                    } else {
-                        eprintln!("warning: {message}");
-                    }
-                }
-                format!(
-                    "<div class=\"rule\" id=\"r-{rule_id}\">\
-                     <a class=\"rule-link\" href=\"#r-{rule_id}\">[{rule_id}]</a>\
-                     </div>\n"
-                )
-            })
-            .to_string()
-    }
-
     /// Generates link references to all rules on all pages, so you can easily
     /// refer to rules anywhere in the book.
     fn auto_link_references(

mdbook-spec/src/rules.rs

@@ -0,0 +1,48 @@
+//! Handling for rule identifiers.
+
+use crate::Spec;
+use mdbook::book::Chapter;
+use once_cell::sync::Lazy;
+use regex::{Captures, Regex};
+use std::collections::BTreeMap;
+use std::path::PathBuf;
+
+/// The Regex for rules like `r[foo]`.
+static RULE_RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"(?m)^r\[([^]]+)]$").unwrap());
+
+impl Spec {
+    /// Converts lines that start with `r[…]` into a "rule" which has special
+    /// styling and can be linked to.
+    pub fn rule_definitions(
+        &self,
+        chapter: &Chapter,
+        found_rules: &mut BTreeMap<String, (PathBuf, PathBuf)>,
+    ) -> String {
+        let source_path = chapter.source_path.clone().unwrap_or_default();
+        let path = chapter.path.clone().unwrap_or_default();
+        RULE_RE
+            .replace_all(&chapter.content, |caps: &Captures<'_>| {
+                let rule_id = &caps[1];
+                if let Some((old, _)) =
+                    found_rules.insert(rule_id.to_string(), (source_path.clone(), path.clone()))
+                {
+                    let message = format!(
+                        "rule `{rule_id}` defined multiple times\n\
+                        First location: {old:?}\n\
+                        Second location: {source_path:?}"
+                    );
+                    if self.deny_warnings {
+                        panic!("error: {message}");
+                    } else {
+                        eprintln!("warning: {message}");
+                    }
+                }
+                format!(
+                    "<div class=\"rule\" id=\"r-{rule_id}\">\
+                     <a class=\"rule-link\" href=\"#r-{rule_id}\">[{rule_id}]</a>\
+                     </div>\n"
+                )
+            })
+            .to_string()
+    }
+}