Support signed numbers as a default value

sqlparser/lib/src/reader/parser.dart

@@ -716,9 +716,8 @@ class Parser {
     final token = _peek;
 
     Literal? _parseInner() {
-      if (_matchOne(TokenType.numberLiteral)) {
-        final number = token as NumericToken;
-        return NumericLiteral(number.parsedNumber, token);
+      if (_check(TokenType.numberLiteral)) {
+        return _numericLiteral();
       }
       if (_matchOne(TokenType.stringLiteral)) {
         return StringLiteral(token as StringLiteralToken);
@@ -752,6 +751,12 @@ class Parser {
     return literal;
   }
 
+  NumericLiteral _numericLiteral() {
+    final number = _consume(TokenType.numberLiteral, 'Expected a number here')
+        as NumericToken;
+    return NumericLiteral(number.parsedNumber, number)..setSpan(number, number);
+  }
+
   Expression _primary() {
     final literal = _literalOrNull();
     if (literal != null) return literal;
@@ -2442,10 +2447,17 @@ class Parser {
       return CheckColumn(resolvedName, expr)..setSpan(first, _previous);
     }
     if (_matchOne(TokenType.$default)) {
-      Expression? expr = _literalOrNull();
+      Expression expr;
 
-      // when not a literal, expect an expression in parentheses
-      expr ??= _expressionInParentheses();
+      if (_match(const [TokenType.plus, TokenType.minus])) {
+        // Signed number
+        final operator = _previous;
+        expr = UnaryExpression(operator, _numericLiteral())
+          ..setSpan(operator, _previous);
+      } else {
+        // Literal or an expression in parentheses
+        expr = _literalOrNull() ?? _expressionInParentheses();
+      }
 
       return Default(resolvedName, expr)..setSpan(first, _previous);
     }

sqlparser/test/parser/create_table_test.dart

@@ -300,4 +300,26 @@ void main() {
       ),
     );
   });
+
+  test('parses DEFAULT with a negative literal', () {
+    // regression test for https://github.com/simolus3/moor/discussions/1550
+    testStatement(
+      'CREATE TABLE a (b INTEGER NOT NULL DEFAULT -1);',
+      CreateTableStatement(
+        tableName: 'a',
+        columns: [
+          ColumnDefinition(columnName: 'b', typeName: 'INTEGER', constraints: [
+            NotNull(null),
+            Default(
+              null,
+              UnaryExpression(
+                Token(TokenType.minus, fakeSpan('-')),
+                NumericLiteral(1, NumericToken(fakeSpan('1'))),
+              ),
+            )
+          ])
+        ],
+      ),
+    );
+  });
 }

sqlparser/test/parser/utils.dart

@@ -38,8 +38,11 @@ void testMoorFile(String moorFile, MoorFile expected) {
 }
 
 void testStatement(String sql, AstNode expected, {bool moorMode = false}) {
-  final parsed =
-      SqlEngine(EngineOptions(useMoorExtensions: moorMode)).parse(sql).rootNode;
+  final result =
+      SqlEngine(EngineOptions(useMoorExtensions: moorMode)).parse(sql);
+  expect(result.errors, isEmpty);
+
+  final parsed = result.rootNode;
   enforceHasSpan(parsed);
   enforceEqual(parsed, expected);
 }