zsh keybindings: make backward-kill-word act on whole quoted string

When using Ctrl+w or Alt+Backspace or Alt+d keyboard shortcuts to delete words backward/forward, I know I can define the WORDCHARS characters: WORDCHARS='~!#$%^&*(){}[]?.+;-' for example, using Ctrl+w from the end of this string, will successively delete each word echo aaa bbb ccc ddd eee but if I have quoted strings, how can I treat the whole quoted block as one entity? echo 'aaa bbb ccc' 'ddd eee fff' so, Ctrl+w should delete whole 'ddd eee fff' in one go. Same behavior should be for strings quoted with double quotes "