Skip language fences for text or unknown filetypes

1 files changed, 22 insertions, 2 deletions

diff --git a/src/renderer.rs b/src/renderer.rs
index 410cbae..6193680 100644
--- a/src/renderer.rs
+++ b/src/renderer.rs
@@ -64,10 +64,11 @@ impl<W: Write> Renderer<W> {
     fn write_file(&mut self, filename: &Path, contents: &str) -> std::io::Result<()> {
         let name = display_path(filename);
         let fence = outer_backticks(contents);
+        let language = detect_language(filename);
         self.log_file_render(filename);
         writeln!(self.output)?;
         writeln!(self.output, "## File: {}", name)?;
-        writeln!(self.output, "{}rust", fence)?;
+        writeln!(self.output, "{}{}", fence, language)?;
         writeln!(self.output, "{}", contents)?;
         writeln!(self.output, "{}", fence)
     }
@@ -141,6 +142,13 @@ fn human_readable_size(bytes: u64) -> String {
     }
 }
 
+fn detect_language(filename: &Path) -> &'static str {
+    match filename.extension().and_then(|e| e.to_str()) {
+        Some("rs") => "rust",
+        _ => "",
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use std::{
@@ -167,7 +175,7 @@ mod tests {
     }
 
     #[test]
-    fn renderer_renders_single_file() {
+    fn renderer_renders_single_rust_file_with_language_fence() {
         let mut output = Vec::new();
         let mut renderer = Renderer::new(&mut output);
 
@@ -219,6 +227,18 @@ mod tests {
     }
 
     #[test]
+    fn unknown_filetype_has_no_language_fence() {
+        let mut output = Vec::new();
+        let mut renderer = Renderer::new(&mut output);
+
+        let input = Cursor::new("hello world");
+        renderer.render_file(Path::new("readme"), input).unwrap();
+        let expected = "\n## File: readme\n```\nhello world\n```\n";
+
+        assert_eq!(String::from_utf8(output).unwrap(), expected);
+    }
+
+    #[test]
     fn renderer_places_placeholder_for_large_files_by_default() {
         let mut output = Vec::new();
         let mut renderer = Renderer::new(&mut output).with_max_file_size(5); // smaller than file