LibSQL: Add parsing and evaluation of BOOLEAN type literals

This allows you to enter TRUE or FALSE in a SQL statement for BOOLEAN
types. Note that this differs from SQLite, which requires entering 1 or
0 for BOOLEANs; having explicit keywords feels a bit more natural.

Tests/LibSQL/TestSqlExpressionParser.cpp

@@ -118,6 +118,23 @@ TEST_CASE(blob_literal)
     validate("x'DEADC0DE'"sv, "DEADC0DE"sv);
 }
 
+TEST_CASE(boolean_literal)
+{
+    auto validate = [](StringView sql, bool expected_value) {
+        auto result = parse(sql);
+        EXPECT(!result.is_error());
+
+        auto expression = result.release_value();
+        EXPECT(is<SQL::AST::BooleanLiteral>(*expression));
+
+        auto const& literal = static_cast<SQL::AST::BooleanLiteral const&>(*expression);
+        EXPECT_EQ(literal.value(), expected_value);
+    };
+
+    validate("TRUE"sv, true);
+    validate("FALSE"sv, false);
+}
+
 TEST_CASE(null_literal)
 {
     auto validate = [](StringView sql) {

Userland/Libraries/LibSQL/AST/AST.h

@@ -357,6 +357,21 @@ private:
     DeprecatedString m_value;
 };
 
+class BooleanLiteral : public Expression {
+public:
+    explicit BooleanLiteral(bool value)
+        : m_value(value)
+    {
+    }
+
+    bool value() const { return m_value; }
+
+    virtual ResultOr<Value> evaluate(ExecutionContext&) const override;
+
+private:
+    bool m_value { false };
+};
+
 class NullLiteral : public Expression {
 public:
     virtual ResultOr<Value> evaluate(ExecutionContext&) const override;

Userland/Libraries/LibSQL/AST/Expression.cpp

@@ -24,6 +24,11 @@ ResultOr<Value> StringLiteral::evaluate(ExecutionContext&) const
     return Value { value() };
 }
 
+ResultOr<Value> BooleanLiteral::evaluate(ExecutionContext&) const
+{
+    return Value { value() };
+}
+
 ResultOr<Value> NullLiteral::evaluate(ExecutionContext&) const
 {
     return Value {};

Userland/Libraries/LibSQL/AST/Parser.cpp

@@ -524,6 +524,10 @@ RefPtr<Expression> Parser::parse_literal_value_expression()
         auto value = consume().value();
         return create_ast_node<BlobLiteral>(value);
     }
+    if (consume_if(TokenType::True))
+        return create_ast_node<BooleanLiteral>(true);
+    if (consume_if(TokenType::False))
+        return create_ast_node<BooleanLiteral>(false);
     if (consume_if(TokenType::Null))
         return create_ast_node<NullLiteral>();
 

Userland/Libraries/LibSQL/AST/Token.h

@@ -69,6 +69,7 @@ namespace SQL::AST {
     __ENUMERATE_SQL_TOKEN("EXISTS", Exists, Keyword)                      \
     __ENUMERATE_SQL_TOKEN("EXPLAIN", Explain, Keyword)                    \
     __ENUMERATE_SQL_TOKEN("FAIL", Fail, Keyword)                          \
+    __ENUMERATE_SQL_TOKEN("FALSE", False, Keyword)                        \
     __ENUMERATE_SQL_TOKEN("FILTER", Filter, Keyword)                      \
     __ENUMERATE_SQL_TOKEN("FIRST", First, Keyword)                        \
     __ENUMERATE_SQL_TOKEN("FOLLOWING", Following, Keyword)                \
@@ -151,6 +152,7 @@ namespace SQL::AST {
     __ENUMERATE_SQL_TOKEN("TO", To, Keyword)                              \
     __ENUMERATE_SQL_TOKEN("TRANSACTION", Transaction, Keyword)            \
     __ENUMERATE_SQL_TOKEN("TRIGGER", Trigger, Keyword)                    \
+    __ENUMERATE_SQL_TOKEN("TRUE", True, Keyword)                          \
     __ENUMERATE_SQL_TOKEN("UNBOUNDED", Unbounded, Keyword)                \
     __ENUMERATE_SQL_TOKEN("UNION", Union, Keyword)                        \
     __ENUMERATE_SQL_TOKEN("UNIQUE", Unique, Keyword)                      \