allow regular pages to have fm

Cargo.toml

@@ -14,7 +14,7 @@ anyhow = "1"
 semver = { version = "1", features = ["serde"] }
 
 pulldown-cmark = "0.9"
-pulldown-cmark-to-cmark = "11.0.1"
+pulldown-cmark-to-cmark = "11"
 
 serde = { version = "1", features = ["derive"] }
 serde_yaml = "0.9"

src/front_matter.rs

@@ -2,10 +2,14 @@ use anyhow::{anyhow, bail, ensure, Result};
 use serde::{Deserialize, Serialize};
 use serde_yaml::{Mapping, Value};
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize, Default)]
+#[serde(deny_unknown_fields)]
 pub struct FrontMatter {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub name: Option<String>,
+
+    // converts absent to/from an empty vec
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub nav: Vec<NavElem>,
 }
 

src/md.rs

@@ -88,9 +88,9 @@ pub fn extract_title_h1(content: &str) -> Result<String> {
     Ok(title)
 }
 
-pub fn take_front_matter(content: &str) -> Result<(Option<FrontMatter>, &str)> {
+pub fn take_front_matter(content: &str) -> Result<(FrontMatter, &str)> {
     let Some(s) = content.strip_prefix("---") else {
-        return Ok((None, content));
+        return Ok((FrontMatter::default(), content));
     };
 
     let Some((fm, remaining)) = s.split_once("\n---") else {
@@ -103,5 +103,11 @@ pub fn take_front_matter(content: &str) -> Result<(Option<FrontMatter>, &str)> {
 pub fn prepend_front_matter(fm: &FrontMatter, content: &str) -> String {
     let fm_yaml = serde_yaml::to_string(fm).expect("ser error????");
 
-    format!("---\n{fm_yaml}---\n{content}")
+    // FIXME use a better check
+    if fm_yaml.trim() == "{}" {
+        // dont put an empty fm block
+        content.to_string()
+    } else {
+        format!("---\n{fm_yaml}---\n{content}")
+    }
 }

src/nav.rs

@@ -8,26 +8,19 @@ pub struct NavPage {
     pub path: Path,
     pub name: String,
 
+    pub fm: FrontMatter,
+
     pub raw_content: String,
     pub built_content: String,
     pub fixed_content: String,
 }
 
-/// An index page (index.md)
-///
-/// name is page.name
-#[derive(Debug)]
-pub struct NavIndex {
-    pub page: NavPage,
-    pub fm: FrontMatter,
-}
-
 /// A folder with an index
 ///
 /// name is index.page.name (ignored for root)
 #[derive(Debug)]
 pub struct NavFolder {
-    pub index: NavIndex,
+    pub index: NavPage,
     pub children: Vec<NavItem>,
 }
 
@@ -60,12 +53,6 @@ impl ForEachPage for NavPage {
     }
 }
 
-impl ForEachPage for NavIndex {
-    fn for_each_page(&self, f: &mut impl FnMut(&NavPage) -> Result<()>) -> Result<()> {
-        self.page.for_each_page(f)
-    }
-}
-
 impl ForEachPage for NavItem {
     fn for_each_page(&self, f: &mut impl FnMut(&NavPage) -> Result<()>) -> Result<()> {
         match self {

src/process.rs

@@ -1,14 +1,17 @@
-use crate::front_matter::{FrontMatter, NavElem};
+use crate::front_matter::NavElem;
 use crate::md;
-use crate::nav::{NavCategory, NavFolder, NavIndex, NavItem, NavPage};
+use crate::nav::{NavCategory, NavFolder, NavItem, NavPage};
 use crate::path::Path;
-use anyhow::{bail, ensure, Result};
+use anyhow::{anyhow, bail, ensure, Result};
 use std::fs;
 
 pub fn process_item(elem: &NavElem, dir: &Path) -> Result<NavItem> {
     match elem {
         NavElem::File { name, path } => {
-            process_page(&dir.join(path), name.clone()).map(NavItem::Page)
+            // regular pages can't have nav
+            process_page(&dir.join(path), name.clone())
+                .and_then(ensure_page_has_no_nav)
+                .map(NavItem::Page)
         }
         NavElem::Folder { name, path } => {
             process_folder(&dir.join(path), name.clone()).map(NavItem::Folder)
@@ -22,17 +25,14 @@ pub fn process_item(elem: &NavElem, dir: &Path) -> Result<NavItem> {
     }
 }
 
-fn process_content(path: &Path, name: Option<String>) -> Result<(NavPage, Option<FrontMatter>)> {
+fn process_page(path: &Path, name: Option<String>) -> Result<NavPage> {
     let raw = unwrap!(fs::read_to_string(path), "could not read file {path}",);
 
-    let (fm, content) = md::take_front_matter(&raw)?;
+    let (fm, content) = unwrap!(md::take_front_matter(&raw), "invalid fm in {path}");
 
     let built_content = md::build(content);
-    let mut fixed_content = md::fix(content);
-
-    if let Some(fm) = &fm {
-        fixed_content = md::prepend_front_matter(fm, &fixed_content);
-    }
+    let fixed_content = md::fix(content);
+    let fixed_content = md::prepend_front_matter(&fm, &fixed_content);
 
     // enforce all files having a title
     let title_h1 = unwrap!(
@@ -42,7 +42,7 @@ fn process_content(path: &Path, name: Option<String>) -> Result<(NavPage, Option
 
     // if fm specifies a name, use it over an assigned name
     // this is mainly only useful for the root index.md
-    let name = if let Some(fm_name) = fm.as_ref().and_then(|fm| fm.name.as_ref()) {
+    let name = if let Some(fm_name) = fm.name.as_ref() {
         ensure!(
             name.is_none(),
             "cannot specify both a fm name and a nav name for {path}"
@@ -53,40 +53,24 @@ fn process_content(path: &Path, name: Option<String>) -> Result<(NavPage, Option
         name.unwrap_or(title_h1)
     };
 
-    Ok((
-        NavPage {
-            path: path.clone(),
-            name,
-            raw_content: raw,
-            built_content,
-            fixed_content,
-        },
+    Ok(NavPage {
+        path: path.clone(),
+        name,
         fm,
-    ))
+        raw_content: raw,
+        built_content,
+        fixed_content,
+    })
 }
 
-pub fn process_page(path: &Path, name: Option<String>) -> Result<NavPage> {
-    let (page, fm) = process_content(path, name)?;
+pub fn process_folder(path: &Path, name: Option<String>) -> Result<NavFolder> {
+    let index = process_page(&path.join("index.md"), name)?;
 
     ensure!(
-        fm.is_none(),
-        "regular (non-index) page {path} cannot have front matter"
+        !index.fm.nav.is_empty(),
+        "index page {path} is missing fm nav"
     );
 
-    Ok(page)
-}
-
-pub fn process_index(path: &Path, name: Option<String>) -> Result<NavIndex> {
-    let (page, fm) = process_content(path, name)?;
-
-    let fm = unwrap!(fm, "index page {path} is missing front matter");
-
-    Ok(NavIndex { page, fm })
-}
-
-pub fn process_folder(path: &Path, name: Option<String>) -> Result<NavFolder> {
-    let index = process_index(&path.join("index.md"), name)?;
-
     let children = index
         .fm
         .nav
@@ -124,7 +108,8 @@ pub fn process_include(dir: &Path, name: String) -> Result<NavCategory> {
             bail!("cannot include/* an index file at {path}");
         }
 
-        children.push(process_page(&path, None)?);
+        // regular pages can't have nav
+        children.push(process_page(&path, None).and_then(ensure_page_has_no_nav)?);
     }
 
     children.sort_by(|x, y| x.name.cmp(&y.name));
@@ -143,3 +128,11 @@ pub fn process_category(dir: &Path, name: String, elems: &[NavElem]) -> Result<N
 
     Ok(NavCategory { name, children })
 }
+
+fn ensure_page_has_no_nav(page: NavPage) -> Result<NavPage> {
+    if page.fm.nav.is_empty() {
+        Ok(page)
+    } else {
+        Err(anyhow!("non index page {} cannot have fm nav", page.path))
+    }
+}