feat: add interface for program ast output

Author: gengjiawen

parser/ast.rs

@@ -2,7 +2,7 @@ use core::fmt;
 use core::fmt::Result;
 use std::fmt::Formatter;
 use lexer::token::{Token, TokenKind, Span};
-use serde::{Deserialize, Serialize, Deserializer, Serializer};
+use serde::{Deserialize, Serialize, Serializer};
 use serde::ser::SerializeStruct;
 
 // still wait for https://github.com/serde-rs/serde/issues/1402

parser/ast_tree_test.rs

@@ -8,7 +8,7 @@ mod tests {
             Ok(node) => {
                 serde_json::to_string_pretty(&node).unwrap()
             }
-            Err(e) => format!("parse error: {}", e[0])
+            Err(e) => panic!("parse error: {}", e[0])
         };
         assert_snapshot!(name, ast, input);
     }

parser/lib.rs

@@ -471,6 +471,17 @@ pub fn parse(input: &str) -> Result<Node, ParseErrors> {
     Ok(Node::Program(program))
 }
 
+pub fn parse_ast_json_string(input: &str) -> Result<String, ParseErrors> {
+    let ast = match parse(input) {
+        Ok(node) => {
+            serde_json::to_string_pretty(&node).unwrap()
+        }
+        Err(e) => return Err(e)
+    };
+
+    return Ok(ast);
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;