uudoc: support after_help and read directly from markdown file

src/bin/uudoc.rs

@@ -91,6 +91,15 @@ fn main() -> io::Result<()> {
             continue;
         }
         let p = format!("docs/src/utils/{}.md", name);
+
+        let markdown = File::open(format!("src/uu/{name}/{name}.md"))
+            .and_then(|mut f: File| {
+                let mut s = String::new();
+                f.read_to_string(&mut s)?;
+                Ok(s)
+            })
+            .ok();
+
         if let Ok(f) = File::create(&p) {
             MDWriter {
                 w: Box::new(f),
@@ -98,6 +107,7 @@ fn main() -> io::Result<()> {
                 name,
                 tldr_zip: &mut tldr_zip,
                 utils_per_platform: &utils_per_platform,
+                markdown,
             }
             .markdown()?;
             println!("Wrote to '{}'", p);
@@ -115,6 +125,7 @@ struct MDWriter<'a, 'b> {
     name: &'a str,
     tldr_zip: &'b mut Option<ZipArchive<File>>,
     utils_per_platform: &'b HashMap<&'b str, Vec<String>>,
+    markdown: Option<String>,
 }
 
 impl<'a, 'b> MDWriter<'a, 'b> {
@@ -124,6 +135,7 @@ impl<'a, 'b> MDWriter<'a, 'b> {
         self.usage()?;
         self.description()?;
         self.options()?;
+        self.after_help()?;
         self.examples()
     }
 
@@ -184,6 +196,10 @@ impl<'a, 'b> MDWriter<'a, 'b> {
     }
 
     fn description(&mut self) -> io::Result<()> {
+        if let Some(after_help) = self.markdown_section("about") {
+            return writeln!(self.w, "\n\n{}", after_help);
+        }
+
         if let Some(about) = self
             .command
             .get_long_about()
@@ -195,6 +211,22 @@ impl<'a, 'b> MDWriter<'a, 'b> {
         }
     }
 
+    fn after_help(&mut self) -> io::Result<()> {
+        if let Some(after_help) = self.markdown_section("after help") {
+            return writeln!(self.w, "\n\n{}", after_help);
+        }
+
+        if let Some(after_help) = self
+            .command
+            .get_after_long_help()
+            .or_else(|| self.command.get_after_help())
+        {
+            writeln!(self.w, "\n\n{}", after_help)
+        } else {
+            Ok(())
+        }
+    }
+
     fn examples(&mut self) -> io::Result<()> {
         if let Some(zip) = self.tldr_zip {
             let content = if let Some(f) =
@@ -295,6 +327,32 @@ impl<'a, 'b> MDWriter<'a, 'b> {
         }
         writeln!(self.w, "</dl>\n")
     }
+
+    fn markdown_section(&self, section: &str) -> Option<String> {
+        let md = self.markdown.as_ref()?;
+        let section = section.to_lowercase();
+
+        fn is_section_header(line: &str, section: &str) -> bool {
+            line.strip_prefix("##")
+                .map_or(false, |l| l.trim().to_lowercase() == section)
+        }
+
+        let result = md
+            .lines()
+            .skip_while(|&l| !is_section_header(l, &section))
+            .skip(1)
+            .take_while(|l| !l.starts_with("##"))
+            .collect::<Vec<_>>()
+            .join("\n")
+            .trim()
+            .to_string();
+
+        if result != "" {
+            Some(result)
+        } else {
+            None
+        }
+    }
 }
 
 fn get_zip_content(archive: &mut ZipArchive<impl Read + Seek>, name: &str) -> Option<String> {

src/uucore_procs/src/lib.rs

@@ -1,4 +1,5 @@
 // Copyright (C) ~ Roy Ivy III <rivy.dev@gmail.com>; MIT license
+// spell-checker:ignore backticks
 
 extern crate proc_macro;
 use std::{fs::File, io::Read, path::PathBuf};
@@ -37,6 +38,19 @@ pub fn main(_args: TokenStream, stream: TokenStream) -> TokenStream {
     TokenStream::from(new)
 }
 
+// FIXME: This is currently a stub. We could do much more here and could
+// even pull in a full markdown parser to get better results.
+/// Render markdown into a format that's easier to read in the terminal.
+///
+/// For now, all this function does is remove backticks.
+/// Some ideas for future improvement:
+/// - Render headings as bold
+/// - Convert triple backticks to indented
+/// - Printing tables in a nice format
+fn render_markdown(s: &str) -> String {
+    s.replace('`', "")
+}
+
 /// Get the usage from the "Usage" section in the help file.
 ///
 /// The usage is assumed to be surrounded by markdown code fences. It may span
@@ -81,7 +95,8 @@ pub fn help_section(input: TokenStream) -> TokenStream {
     let section = get_argument(&input, 0, "section");
     let filename = get_argument(&input, 1, "filename");
     let text = parse_help(&section, &filename);
-    TokenTree::Literal(Literal::string(&text)).into()
+    let rendered = render_markdown(&text);
+    TokenTree::Literal(Literal::string(&rendered)).into()
 }
 
 /// Get an argument from the input vector of `TokenTree`.