Add a --dump-ts debug option

CHANGELOG.md

@@ -62,7 +62,8 @@ delimiter over a delimiter that gave contiguous changes.
 
 Removed the `--width` argument.
 
-Added a debug option `--dump-syntax`.
+Added debug options `--dump-syntax` and `--dump-ts` for viewing parse
+trees. The output of these files may change without notice.
 
 ## 0.6
 

src/main.rs

@@ -39,6 +39,9 @@ enum Mode {
         lhs_path: String,
         rhs_path: String,
     },
+    DumpTreeSitter {
+        path: String,
+    },
     DumpSyntax {
         path: String,
     },
@@ -53,17 +56,34 @@ fn parse_args() -> Mode {
             .arg(Arg::with_name("dump-syntax").long("dump-syntax").help(
                 "Parse a single file with tree-sitter and display the difftastic syntax tree.",
             ))
+            .arg(Arg::with_name("dump-ts").long("dump-ts").help(
+                "Parse a single file with tree-sitter and display the tree-sitter parse tree.",
+            ))
             .arg(Arg::with_name("positional_args").multiple(true))
             .setting(AppSettings::ArgRequiredElseHelp)
             .get_matches();
 
     let args: Vec<_> = matches.values_of_lossy("positional_args").unwrap();
 
-    if matches.is_present("dump-tree-sitter") {
+    if matches.is_present("dump-syntax") {
         if args.len() == 1 {
             return Mode::DumpSyntax {
                 path: args[0].clone(),
             };
+        } else {
+            // TODO: delegate this parsing to clap.
+            panic!(
+                "Error: --dump-syntax takes one argument, but got: {}",
+                args.len()
+            );
+        }
+    }
+
+    if matches.is_present("dump-ts") {
+        if args.len() == 1 {
+            return Mode::DumpTreeSitter {
+                path: args[0].clone(),
+            };
         } else {
             // TODO: delegate this parsing to clap.
             panic!(
@@ -119,6 +139,22 @@ fn main() {
 
     let mode = parse_args();
     let (display_path, lhs_path, rhs_path) = match mode {
+        Mode::DumpTreeSitter { path } => {
+            let extension = Path::new(&path).extension();
+            let extension = extension.unwrap_or_else(|| OsStr::new(""));
+            match tsp::from_extension(extension) {
+                Some(ts_lang) => {
+                    let bytes = read_or_die(&path);
+                    let src = String::from_utf8_lossy(&bytes).to_string();
+                    let tree = tsp::parse_to_tree(&src, &ts_lang);
+                    println!("{:#?}", tree.root_node());
+                }
+                None => {
+                    println!("No tree-sitter parser for extension: {:?}", extension);
+                }
+            }
+            return;
+        }
         Mode::DumpSyntax { path } => {
             let extension = Path::new(&path).extension();
             let extension = extension.unwrap_or_else(|| OsStr::new(""));
@@ -127,7 +163,7 @@ fn main() {
                     let bytes = read_or_die(&path);
                     let src = String::from_utf8_lossy(&bytes).to_string();
                     let ast = tsp::parse(&arena, &src, &ts_lang);
-                    dbg!(ast);
+                    println!("{:#?}", ast);
                 }
                 None => {
                     println!("No tree-sitter parser for extension: {:?}", extension);

src/tree_sitter_parser.rs

@@ -102,17 +102,23 @@ pub fn from_extension(extension: &OsStr) -> Option<TreeSitterConfig> {
     }
 }
 
-pub fn parse<'a>(
-    arena: &'a Arena<Syntax<'a>>,
-    src: &str,
-    config: &TreeSitterConfig,
-) -> Vec<&'a Syntax<'a>> {
+/// Parse `src` with tree-sitter.
+pub fn parse_to_tree(src: &str, config: &TreeSitterConfig) -> tree_sitter::Tree {
     let mut parser = Parser::new();
     parser
         .set_language(config.language)
         .expect("Incompatible tree-sitter version");
 
-    let tree = parser.parse(src, None).unwrap();
+    parser.parse(src, None).unwrap()
+}
+
+/// Parse `src` with tree-sitter and convert to difftastic Syntax.
+pub fn parse<'a>(
+    arena: &'a Arena<Syntax<'a>>,
+    src: &str,
+    config: &TreeSitterConfig,
+) -> Vec<&'a Syntax<'a>> {
+    let tree = parse_to_tree(src, config);
 
     let nl_pos = NewlinePositions::from(src);
     let mut cursor = tree.walk();