fix: support numbers with plus sign at start (#58)

Author: dsherret

src/ast.rs

@@ -69,8 +69,8 @@ impl<'a> From<Value<'a>> for serde_json::Value {
       Value::BooleanLit(b) => serde_json::Value::Bool(b.value),
       Value::NullKeyword(_) => serde_json::Value::Null,
       Value::NumberLit(num) => {
-        // Check if this is a hexadecimal literal (0x or 0X prefix)
-        let num_str = num.value.trim_start_matches('-');
+        // check if this is a hexadecimal literal (0x or 0X prefix)
+        let num_str = num.value.trim_start_matches(['-', '+']);
         if num_str.len() > 2 && (num_str.starts_with("0x") || num_str.starts_with("0X")) {
           // Parse hexadecimal and convert to decimal
           let hex_part = &num_str[2..];
@@ -86,8 +86,9 @@ impl<'a> From<Value<'a>> for serde_json::Value {
             Err(_) => serde_json::Value::String(num.value.to_string()),
           }
         } else {
-          // Standard decimal number
-          match serde_json::Number::from_str(num.value) {
+          // standard decimal number
+          let num_for_parsing = num.value.trim_start_matches('+');
+          match serde_json::Number::from_str(num_for_parsing) {
             Ok(number) => serde_json::Value::Number(number),
             Err(_) => serde_json::Value::String(num.value.to_string()),
           }

src/cst/mod.rs

@@ -1444,7 +1444,7 @@ impl CstNumberLit {
     let raw = self.0.borrow().value.clone();
 
     // check if this is a hexadecimal literal (0x or 0X prefix)
-    let num_str = raw.trim_start_matches('-');
+    let num_str = raw.trim_start_matches(['-', '+']);
     if num_str.len() > 2 && (num_str.starts_with("0x") || num_str.starts_with("0X")) {
       // parse hexadecimal and convert to decimal
       let hex_part = &num_str[2..];
@@ -1460,8 +1460,9 @@ impl CstNumberLit {
         Err(_) => Some(serde_json::Value::String(raw)),
       }
     } else {
-      // standard decimal number
-      match serde_json::Number::from_str(&raw) {
+      // standard decimal number - strip leading + if present (serde_json doesn't accept it)
+      let num_for_parsing = raw.trim_start_matches('+');
+      match serde_json::Number::from_str(num_for_parsing) {
         Ok(number) => Some(serde_json::Value::Number(number)),
         // if the number is invalid, return it as a string (same behavior as AST conversion)
         Err(_) => Some(serde_json::Value::String(raw)),

src/parse_to_ast.rs

@@ -602,4 +602,17 @@ mod tests {
       );
     }
   }
+
+  #[test]
+  fn it_should_parse_unary_plus_numbers() {
+    let result = parse_to_ast(r#"{ "test": +42 }"#, &Default::default(), &Default::default()).unwrap();
+
+    let value = result.value.unwrap();
+    let obj = value.as_object().unwrap();
+    assert_eq!(obj.properties.len(), 1);
+    assert_eq!(obj.properties[0].name.as_str(), "test");
+
+    let number_value = obj.properties[0].value.as_number_lit().unwrap();
+    assert_eq!(number_value.value, "+42");
+  }
 }

src/scanner.rs

@@ -79,7 +79,7 @@ impl<'a> Scanner<'a> {
           _ => Err(self.create_error_for_current_token(ParseErrorKind::UnexpectedToken)),
         },
         _ => {
-          if current_char == '-' || self.is_digit() {
+          if current_char == '-' || current_char == '+' || self.is_digit() {
             self.parse_number()
           } else if self.try_move_word("true") {
             Ok(Token::Boolean(true))
@@ -154,7 +154,8 @@ impl<'a> Scanner<'a> {
   fn parse_number(&mut self) -> Result<Token<'a>, ParseError> {
     let start_byte_index = self.byte_index;
 
-    if self.is_negative_sign() {
+    // handle unary plus or minus
+    if self.is_negative_sign() || self.is_positive_sign() {
       self.move_next_char();
     }
 
@@ -423,6 +424,10 @@ impl<'a> Scanner<'a> {
     self.current_char() == Some('-')
   }
 
+  fn is_positive_sign(&self) -> bool {
+    self.current_char() == Some('+')
+  }
+
   fn is_decimal_point(&self) -> bool {
     self.current_char() == Some('.')
   }
@@ -540,6 +545,22 @@ mod tests {
     );
   }
 
+  #[test]
+  fn it_tokenizes_unary_plus_numbers() {
+    assert_has_tokens(
+      "+42, +0.5, +1e10, +0xFF",
+      vec![
+        Token::Number("+42"),
+        Token::Comma,
+        Token::Number("+0.5"),
+        Token::Comma,
+        Token::Number("+1e10"),
+        Token::Comma,
+        Token::Number("+0xFF"),
+      ],
+    );
+  }
+
   #[test]
   fn it_errors_invalid_exponent() {
     assert_has_error(

src/serde.rs

@@ -104,4 +104,30 @@ mod tests {
 
     assert_eq!(result, Some(SerdeValue::Object(expected_value)));
   }
+
+  #[test]
+  fn it_should_parse_unary_plus_numbers() {
+    let result = parse_to_serde_value(
+      r#"{
+        "pos1": +42,
+        "pos2": +0.5,
+        "pos3": +1e10
+      }"#,
+      &Default::default(),
+    )
+    .unwrap();
+
+    let mut expected_value = serde_json::map::Map::new();
+    expected_value.insert("pos1".to_string(), SerdeValue::Number(serde_json::Number::from(42)));
+    expected_value.insert(
+      "pos2".to_string(),
+      SerdeValue::Number(serde_json::Number::from_str("0.5").unwrap()),
+    );
+    expected_value.insert(
+      "pos3".to_string(),
+      SerdeValue::Number(serde_json::Number::from_str("1e10").unwrap()),
+    );
+
+    assert_eq!(result, Some(SerdeValue::Object(expected_value)));
+  }
 }