Include code without hidden lines for nostarch files

Cargo.toml

@@ -25,6 +25,10 @@ path = "tools/src/bin/link2print.rs"
 name = "release_listings"
 path = "tools/src/bin/release_listings.rs"
 
+[[bin]]
+name = "remove_hidden_lines"
+path = "tools/src/bin/remove_hidden_lines.rs"
+
 [[bin]]
 name = "remove_links"
 path = "tools/src/bin/remove_links.rs"

tools/nostarch.sh

@@ -6,19 +6,22 @@ cargo build --release
 
 mkdir -p tmp
 rm -rf tmp/*.md
+rm -rf tmp/markdown
 
-# Get all the Markdown files in the src dir,
-ls src/${1:-""}*.md | \
-# except for `SUMMARY.md`.
-grep -v SUMMARY.md | \
+# Render the book as Markdown to include all the code listings
+MDBOOK_OUTPUT__MARKDOWN=1 mdbook build -d tmp
+
+# Get all the Markdown files
+ls tmp/markdown/${1:-""}*.md | \
 # Extract just the filename so we can reuse it easily.
 xargs -n 1 basename | \
 # Remove all links followed by `<!-- ignore -->``, then
 # Change all remaining links from Markdown to italicized inline text.
 while IFS= read -r filename; do
-  < "src/$filename" ./target/release/remove_links \
+  < "tmp/markdown/$filename" ./target/release/remove_links \
     | ./target/release/link2print \
-    | ./target/release/remove_markup > "tmp/$filename"
+    | ./target/release/remove_markup \
+    | ./target/release/remove_hidden_lines > "tmp/$filename"
 done
 # Concatenate the files into the `nostarch` dir.
 ./target/release/concat_chapters tmp nostarch

tools/src/bin/remove_hidden_lines.rs

@@ -0,0 +1,85 @@
+use std::io;
+use std::io::prelude::*;
+
+fn main() {
+    write_md(remove_hidden_lines(&read_md()));
+}
+
+fn read_md() -> String {
+    let mut buffer = String::new();
+    match io::stdin().read_to_string(&mut buffer) {
+        Ok(_) => buffer,
+        Err(error) => panic!(error),
+    }
+}
+
+fn write_md(output: String) {
+    write!(io::stdout(), "{}", output).unwrap();
+}
+
+
+fn remove_hidden_lines(input: &str) -> String {
+    let mut resulting_lines = vec![];
+    let mut within_codeblock = false;
+
+    for line in input.lines() {
+        if line.starts_with("```") {
+            within_codeblock = !within_codeblock;
+        }
+
+        if !within_codeblock || (!line.starts_with("# ") && line != "#") {
+            resulting_lines.push(line)
+        }
+    }
+
+    resulting_lines.join("\n")
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::remove_hidden_lines;
+
+    #[test]
+    fn hidden_line_in_code_block_is_removed() {
+        let input = r#"
+In this listing:
+
+```
+fn main() {
+# secret
+}
+```
+
+you can see that...
+        "#;
+        let output = remove_hidden_lines(input);
+
+        let desired_output = r#"
+In this listing:
+
+```
+fn main() {
+}
+```
+
+you can see that...
+        "#;
+
+        assert_eq!(output, desired_output);
+    }
+
+    #[test]
+    fn headings_arent_removed() {
+        let input = r#"
+# Heading 1
+        "#;
+        let output = remove_hidden_lines(input);
+
+        let desired_output = r#"
+# Heading 1
+        "#;
+
+        assert_eq!(output, desired_output);
+
+    }
+}