Add TIME support to scalar functions

Author: suketa

ext/duckdb/scalar_function.c

@@ -294,6 +294,21 @@ static void vector_set_value_at(duckdb_vector vector, duckdb_logical_type elemen
             ((duckdb_date *)vector_data)[index] = date;
             break;
         }
+        case DUCKDB_TYPE_TIME: {
+            // Convert Ruby Time to DuckDB time (time-of-day only)
+            if (!rb_obj_is_kind_of(value, rb_cTime)) {
+                rb_raise(rb_eTypeError, "Expected Time object for TIME");
+            }
+            
+            VALUE hour = rb_funcall(value, rb_intern("hour"), 0);
+            VALUE min = rb_funcall(value, rb_intern("min"), 0);
+            VALUE sec = rb_funcall(value, rb_intern("sec"), 0);
+            VALUE usec = rb_funcall(value, rb_intern("usec"), 0);
+            
+            duckdb_time time = rbduckdb_to_duckdb_time_from_value(hour, min, sec, usec);
+            ((duckdb_time *)vector_data)[index] = time;
+            break;
+        }
         default:
             rb_raise(rb_eArgError, "Unsupported return type for scalar function");
             break;

lib/duckdb/scalar_function.rb

@@ -4,7 +4,7 @@ module DuckDB
   # DuckDB::ScalarFunction encapsulates DuckDB's scalar function
   class ScalarFunction
     # Sets the return type for the scalar function.
-    # Currently supports BIGINT, BLOB, BOOLEAN, DATE, DOUBLE, FLOAT, INTEGER, TIMESTAMP, and VARCHAR types.
+    # Currently supports BIGINT, BLOB, BOOLEAN, DATE, DOUBLE, FLOAT, INTEGER, TIME, TIMESTAMP, and VARCHAR types.
     #
     # @param logical_type [DuckDB::LogicalType] the return type
     # @return [DuckDB::ScalarFunction] self
@@ -13,10 +13,10 @@ def return_type=(logical_type)
       raise DuckDB::Error, 'logical_type must be a DuckDB::LogicalType' unless logical_type.is_a?(DuckDB::LogicalType)
 
       # Check if the type is supported
-      unless %i[bigint blob boolean date double float integer timestamp varchar].include?(logical_type.type)
+      unless %i[bigint blob boolean date double float integer time timestamp varchar].include?(logical_type.type)
         raise DuckDB::Error,
-              'Only BIGINT, BLOB, BOOLEAN, DATE, DOUBLE, FLOAT, INTEGER, TIMESTAMP, and VARCHAR return types are ' \
-              'currently supported'
+              'Only BIGINT, BLOB, BOOLEAN, DATE, DOUBLE, FLOAT, INTEGER, TIME, TIMESTAMP, and VARCHAR return ' \
+              'types are currently supported'
       end
 
       _set_return_type(logical_type)

test/duckdb_test/scalar_function_test.rb

@@ -37,10 +37,10 @@ def test_return_type_setter
 
     def test_return_type_setter_raises_error_for_unsupported_type
       sf = DuckDB::ScalarFunction.new
-      time_type = DuckDB::LogicalType.new(14) # DUCKDB_TYPE_TIME (unsupported)
+      interval_type = DuckDB::LogicalType.new(15) # DUCKDB_TYPE_INTERVAL (unsupported)
 
       error = assert_raises(DuckDB::Error) do
-        sf.return_type = time_type
+        sf.return_type = interval_type
       end
 
       assert_match(/only.*supported/i, error.message)
@@ -291,5 +291,28 @@ def test_scalar_function_date_return_type # rubocop:disable Metrics/AbcSize, Met
       assert_equal Date.new(2024, 1, 16), rows[0][0]
       assert_equal Date.new(2024, 12, 26), rows[1][0]
     end
+
+    def test_scalar_function_time_return_type # rubocop:disable Metrics/AbcSize, Metrics/MethodLength, Minitest/MultipleAssertions
+      @con.execute('SET threads=1')
+      @con.execute('CREATE TABLE test_table (t TIME)')
+      @con.execute("INSERT INTO test_table VALUES ('10:30:00'), ('23:59:59')")
+
+      sf = DuckDB::ScalarFunction.new
+      sf.name = 'add_one_hour'
+      sf.add_parameter(DuckDB::LogicalType.new(14)) # TIME (type ID 14)
+      sf.return_type = DuckDB::LogicalType.new(14) # TIME
+      sf.set_function { |time| time + 3600 } # Add 1 hour (3600 seconds)
+
+      @con.register_scalar_function(sf)
+      result = @con.execute('SELECT add_one_hour(t) FROM test_table ORDER BY t')
+      rows = result.to_a
+
+      assert_equal 2, rows.size
+      # TIME values are returned as Time objects with today's date
+      assert_equal 11, rows[0][0].hour
+      assert_equal 30, rows[0][0].min
+      assert_equal 0, rows[1][0].hour
+      assert_equal 59, rows[1][0].min
+    end
   end
 end