Introduction
No dedicated formatting template is foreseen for formatting sets. For advanced features to convert sets to strings with opening, closing and separator strings, use the join() function instead.
echo( str( { 1, true, 'true', {b1, b2, { b2a, b2b }, b3 } } ) );{1,true,'true',{'b1','b2',{'b2a','b2b'},'b3'}}