Add tree option to CLI args

src/evaluator.rs

@@ -73,7 +73,7 @@ impl Debug for Evaluator<'_, '_> {
 }
 
 impl<'context, 'code> Evaluator<'context, 'code> {
-    fn new(mut parser: Parser, context: &'context mut Map, source: &'code str) -> Self {
+    pub fn new(mut parser: Parser, context: &'context mut Map, source: &'code str) -> Self {
         let syntax_tree = parser.parse(source, None).unwrap();
 
         Evaluator {
@@ -84,7 +84,7 @@ impl<'context, 'code> Evaluator<'context, 'code> {
         }
     }
 
-    fn run(self) -> Result<Value> {
+    pub fn run(self) -> Result<Value> {
         let mut cursor = self.syntax_tree.walk();
         let root_node = cursor.node();
         let mut prev_result = Ok(Value::Empty);
@@ -96,6 +96,10 @@ impl<'context, 'code> Evaluator<'context, 'code> {
 
         prev_result
     }
+
+    pub fn syntax_tree(&self) -> String {
+        self.syntax_tree.root_node().to_sexp()
+    }
 }
 
 #[cfg(test)]

src/main.rs

@@ -9,10 +9,11 @@ use rustyline::{
     history::DefaultHistory,
     Completer, Context, Editor, Helper, Validator,
 };
+use tree_sitter::Parser as TSParser;
 
 use std::borrow::Cow;
 
-use dust_lang::{evaluate_with_context, Map, Value};
+use dust_lang::{evaluate_with_context, language, Evaluator, Map, Value};
 
 /// Command-line arguments to be parsed.
 #[derive(Parser, Debug)]
@@ -30,6 +31,10 @@ struct Args {
     #[arg(short = 'p', long)]
     input_path: Option<String>,
 
+    /// A path to file whose contents will be assigned to the "input" variable.
+    #[arg(short = 't', long = "tree")]
+    show_syntax_tree: bool,
+
     /// Location of the file to run.
     path: Option<String>,
 }
@@ -68,7 +73,16 @@ async fn main() {
             .insert("input".to_string(), Value::String(file_contents));
     }
 
-    let eval_result = evaluate_with_context(&source, &mut context);
+    let mut parser = TSParser::new();
+    parser.set_language(language()).unwrap();
+
+    let evaluator = Evaluator::new(parser, &mut context, &source);
+
+    if args.show_syntax_tree {
+        println!("{}", evaluator.syntax_tree());
+    }
+
+    let eval_result = evaluator.run();
 
     match eval_result {
         Ok(value) => {