chore: improve statement type generation

Author: gengjiawen

parser/ast.rs

@@ -46,20 +46,21 @@ impl fmt::Display for Program {
 }
 
 #[derive(Clone, Debug, Eq, Serialize, Deserialize, Hash, PartialEq)]
+#[serde(untagged)]
+pub enum Statement {
+    Let(Let),
+    Return(Expression), // todo refactor to struct
+    Expr(Expression),
+}
+
+#[derive(Clone, Debug, Eq, Serialize, Deserialize, Hash, PartialEq)]
+#[serde(tag = "type")]
 pub struct Let {
     pub identifier: Token, // rust can't do precise type with enum
     pub expr: Expression,
     pub span: Span,
 }
 
-#[derive(Clone, Debug, Eq, Serialize, Deserialize, Hash, PartialEq)]
-#[serde(tag = "stmt_type")]
-pub enum Statement {
-    Let(Let),
-    Return(Expression),
-    Expr(Expression),
-}
-
 impl fmt::Display for Statement {
     fn fmt(&self, f: &mut Formatter<'_>) -> Result {
         match self {

parser/snapshots/parser__ast_tree_test__tests__test_array.snap

@@ -7,7 +7,6 @@ expression: "[1, true]"
     "type": "Program",
     "body": [
       {
-        "stmt_type": "Expr",
         "expr_type": "LITERAL",
         "type": "Array",
         "elements": [

parser/snapshots/parser__ast_tree_test__tests__test_binary.snap

@@ -7,7 +7,6 @@ expression: 1 + 2 * 3
     "type": "Program",
     "body": [
       {
-        "stmt_type": "Expr",
         "expr_type": "INFIX",
         "op": {
           "span": {

parser/snapshots/parser__ast_tree_test__tests__test_func_call.snap

@@ -7,7 +7,6 @@ expression: "add(1, 2)"
     "type": "Program",
     "body": [
       {
-        "stmt_type": "Expr",
         "expr_type": "FunctionCall",
         "callee": {
           "expr_type": "IDENTIFIER",

parser/snapshots/parser__ast_tree_test__tests__test_func_declaration.snap

@@ -7,14 +7,12 @@ expression: "fn(x) { x };"
     "type": "Program",
     "body": [
       {
-        "stmt_type": "Expr",
         "expr_type": "FUNCTION",
         "params": [
           "x"
         ],
         "body": [
           {
-            "stmt_type": "Expr",
             "expr_type": "IDENTIFIER",
             "name": "x",
             "span": {

parser/snapshots/parser__ast_tree_test__tests__test_hash.snap

@@ -7,7 +7,6 @@ expression: "{\"a\": 1}"
     "type": "Program",
     "body": [
       {
-        "stmt_type": "Expr",
         "expr_type": "LITERAL",
         "type": "Hash",
         "elements": [

parser/snapshots/parser__ast_tree_test__tests__test_if.snap

@@ -7,7 +7,6 @@ expression: "if (x < y) { x } else { y }"
     "type": "Program",
     "body": [
       {
-        "stmt_type": "Expr",
         "expr_type": "IF",
         "condition": {
           "expr_type": "INFIX",
@@ -43,7 +42,6 @@ expression: "if (x < y) { x } else { y }"
         },
         "consequent": [
           {
-            "stmt_type": "Expr",
             "expr_type": "IDENTIFIER",
             "name": "x",
             "span": {
@@ -54,7 +52,6 @@ expression: "if (x < y) { x } else { y }"
         ],
         "alternate": [
           {
-            "stmt_type": "Expr",
             "expr_type": "IDENTIFIER",
             "name": "y",
             "span": {

parser/snapshots/parser__ast_tree_test__tests__test_index.snap

@@ -7,7 +7,6 @@ expression: "a[1]"
     "type": "Program",
     "body": [
       {
-        "stmt_type": "Expr",
         "expr_type": "Index",
         "object": {
           "expr_type": "IDENTIFIER",

parser/snapshots/parser__ast_tree_test__tests__test_let.snap

@@ -7,7 +7,7 @@ expression: let a = 3
     "type": "Program",
     "body": [
       {
-        "stmt_type": "Let",
+        "type": "Let",
         "identifier": {
           "span": {
             "start": 4,

parser/snapshots/parser__ast_tree_test__tests__test_return.snap

@@ -7,7 +7,6 @@ expression: return 3
     "type": "Program",
     "body": [
       {
-        "stmt_type": "Return",
         "expr_type": "LITERAL",
         "type": "Integer",
         "raw": 3,