Derive Macro VTabModuleDerive

#[derive(VTabModuleDerive)]

Macro to derive a VTabModule for your extension. This macro will generate the necessary functions to register your module with core. You must implement the VTabModule trait for your struct, and the VTabCursor trait for your cursor.

#[derive(Debug, VTabModuleDerive)]
struct CsvVTab;
impl VTabModule for CsvVTab {
   type VCursor = CsvCursor;
   const NAME: &'static str = "csv_data";

   /// Declare the schema for your virtual table
   fn connect(api: &ExtensionApi) -> ResultCode {
       let sql = "CREATE TABLE csv_data(
           name TEXT,
           age TEXT,
           city TEXT
       )";
       api.declare_virtual_table(Self::NAME, sql)
   }
   /// Open the virtual table and return a cursor
 fn open() -> Self::VCursor {
      let csv_content = fs::read_to_string("data.csv").unwrap_or_default();
      let rows: Vec<Vec<String>> = csv_content
          .lines()
          .skip(1)
          .map(|line| {
              line.split(',')
                  .map(|s| s.trim().to_string())
                  .collect()
          })
          .collect();
      CsvCursor { rows, index: 0 }
  }
  /// Filter the virtual table based on arguments (omitted here for simplicity)
  fn filter(_cursor: &mut Self::VCursor, _arg_count: i32, _args: &[Value]) -> ResultCode {
      ResultCode::OK
  }
  /// Return the value for a given column index
  fn column(cursor: &Self::VCursor, idx: u32) -> Value {
     cursor.column(idx)
 }
 /// Move the cursor to the next row
 fn next(cursor: &mut Self::VCursor) -> ResultCode {
     if cursor.index < cursor.rows.len() - 1 {
         cursor.index += 1;
         ResultCode::OK
     } else {
         ResultCode::EOF
     }
 }
 fn eof(cursor: &Self::VCursor) -> bool {
     cursor.index >= cursor.rows.len()
 }
 #[derive(Debug)]
struct CsvCursor {
  rows: Vec<Vec<String>>,
  index: usize,

impl CsvCursor {
  /// Returns the value for a given column index.
  fn column(&self, idx: u32) -> Value {
      let row = &self.rows[self.index];
      if (idx as usize) < row.len() {
          Value::from_text(&row[idx as usize])
      } else {
          Value::null()
      }
  }
// Implement the VTabCursor trait for your virtual cursor
impl VTabCursor for CsvCursor {
  fn next(&mut self) -> ResultCode {
      Self::next(self)
  }
 fn eof(&self) -> bool {
     self.index >= self.rows.len()
 }
 fn column(&self, idx: u32) -> Value {
     self.column(idx)
 }
 fn rowid(&self) -> i64 {
     self.index as i64
 }