feat(core): add bash syntax highlighting

Register the Tree-sitter Bash grammar for shell file extensions and Markdown code fences. This lets `.sh`, `.bash`, and `.zsh` files plus `bash`, `sh`, `shell`, and `zsh` fences use the compiled-in highlighter.

Document Bash as syntax-highlighted and keep the LSP wording separate from the syntax list.

Author: fcoury

Cargo.lock

@@ -31,6 +31,7 @@ thiserror = "1.0"
 tokio = { version = "1.41.0", features = ["full"] }
 toml = "0.8.10"
 tree-sitter = "0.25"
+tree-sitter-bash = "0.25.1"
 tree-sitter-javascript = "0.25.0"
 tree-sitter-json = "0.24.8"
 tree-sitter-md = "0.5.3"

Cargo.toml

@@ -90,8 +90,9 @@ cursor_line = true
 enabled = true
 
 # Built-in syntax highlighting covers Rust, Markdown, JavaScript,
-# TypeScript/TSX, JSON, TOML, YAML, and Python. LSP defaults are provided for
-# those file types and start only when a matching file is opened.
+# TypeScript/TSX, JSON, TOML, YAML, Python, and Bash. LSP defaults are
+# provided for common language-server-backed file types and start only when a
+# matching file is opened.
 
 [lsp.servers.typescript]
 command = "typescript-language-server"

README.md

@@ -244,6 +244,7 @@ fn language_id_for_name(name: &str) -> Option<&'static str> {
         "yaml" | "yml" => Some("yaml"),
         "py" | "python" => Some("python"),
         "md" | "markdown" => Some("markdown"),
+        "bash" | "sh" | "shell" | "zsh" => Some("bash"),
         _ => None,
     }
 }
@@ -319,6 +320,13 @@ fn language_definitions() -> Vec<LanguageDefinition> {
             highlight_query: tree_sitter_python::HIGHLIGHTS_QUERY,
             injection_query: None,
         },
+        LanguageDefinition {
+            id: "bash",
+            extensions: &["sh", "bash", "zsh"],
+            language: || tree_sitter_bash::LANGUAGE.into(),
+            highlight_query: tree_sitter_bash::HIGHLIGHT_QUERY,
+            injection_query: None,
+        },
     ]
 }
 
@@ -426,6 +434,10 @@ mod tests {
             highlighter.language_id_for_file(Some("config.yml")),
             Some("yaml")
         );
+        assert_eq!(
+            highlighter.language_id_for_file(Some("script.sh")),
+            Some("bash")
+        );
         assert_eq!(highlighter.language_id_for_file(Some("LICENSE")), None);
     }
 
@@ -441,6 +453,7 @@ mod tests {
             ("toml", "value = true\n"),
             ("yaml", "value: true\n"),
             ("python", "def main():\n    return True\n"),
+            ("bash", "if [ -f Cargo.toml ]; then\n  echo yes\nfi\n"),
         ];
         let mut highlighter = highlighter();
 
@@ -461,6 +474,8 @@ mod tests {
         assert_eq!(highlighter.language_id_for_name("py"), Some("python"));
         assert_eq!(highlighter.language_id_for_name("yml"), Some("yaml"));
         assert_eq!(highlighter.language_id_for_name("ts"), Some("typescript"));
+        assert_eq!(highlighter.language_id_for_name("sh"), Some("bash"));
+        assert_eq!(highlighter.language_id_for_name("shell"), Some("bash"));
         assert_eq!(highlighter.language_id_for_name("unknown"), None);
     }
 
@@ -528,6 +543,30 @@ mod tests {
         );
     }
 
+    #[test]
+    fn markdown_highlights_bash_fenced_code() {
+        let mut highlighter = highlighter();
+        let code = "```sh\nif [ -f Cargo.toml ]; then\n  echo yes\nfi\n```\n";
+        let styles = highlighter
+            .highlight_for_file(Some("README.md"), code)
+            .unwrap();
+        let if_start = code.find("if").unwrap();
+        let echo_start = code.find("echo").unwrap();
+
+        assert!(
+            styles
+                .iter()
+                .any(|style| style.start <= if_start && style.end >= if_start + 2),
+            "fenced shell `if` keyword should be highlighted at Markdown byte offsets"
+        );
+        assert!(
+            styles
+                .iter()
+                .any(|style| style.start <= echo_start && style.end >= echo_start + 4),
+            "fenced shell command should be highlighted at Markdown byte offsets"
+        );
+    }
+
     #[test]
     fn markdown_resolves_fenced_code_by_registered_extension() {
         let mut highlighter = highlighter();