Scan @-variable tokens (not used yet)

sqlparser/lib/src/reader/tokenizer/scanner.dart

@@ -152,6 +152,11 @@ class Scanner {
         final name = _matchColumnName();
         tokens.add(DollarSignVariableToken(_currentSpan, name));
         break;
+      case '@':
+        final name = _matchColumnName();
+        tokens.add(AtSignVariableToken(_currentSpan, name));
+        break;
+        break;
       case ';':
         _addToken(TokenType.semicolon);
         break;
@@ -167,7 +172,6 @@ class Scanner {
         _string();
         break;
       case '"':
-        // todo sqlite also allows string literals with double ticks, we don't
         _identifier(escapedInQuotes: true);
         break;
       case '`':

sqlparser/lib/src/reader/tokenizer/token.dart

@@ -42,8 +42,7 @@ enum TokenType {
   questionMarkVariable,
   colon,
   colonVariable,
-  // todo at is not used at the moment
-  at,
+  atSignVariable,
   dollarSignVariable,
 
   stringLiteral,
@@ -362,6 +361,13 @@ class DollarSignVariableToken extends Token {
       : super(TokenType.dollarSignVariable, span);
 }
 
+class AtSignVariableToken extends Token {
+  final String name;
+
+  AtSignVariableToken(FileSpan span, this.name)
+      : super(TokenType.atSignVariable, span);
+}
+
 /// Inline Dart appearing in a create table statement. Only parsed when the moor
 /// extensions are enabled. Dart code is wrapped in backticks.
 class InlineDartToken extends Token {

sqlparser/test/scanner/single_token_tests.dart

@@ -44,6 +44,8 @@ Map<String, TokenType> testCases = {
   '0Xf13A': TokenType.numberLiteral,
   'SELECT': TokenType.select,
   '"UPDATE"': TokenType.identifier,
+  '@foo': TokenType.atSignVariable,
+  ':named': TokenType.colonVariable,
 };
 
 void main() {