regex match space not in parenthesis, accolades or squared barackets

Question

I'm trying to split a sentence by whitespace/space but I must exclude space located inside parenthesis (), accolades {} or squared brackets [].

ex string: [apples carrots] (car plane train) {food water} foo bar should result in an array containing:

• [apples carrots]
• (car plane train)
• {food water}
• foo
• bar

Any ideas?

Answer 1

Not splitting, but matching and trimming. Example is in JavaScript, you can try it out in browser console:

var a = '[apples carrots] (car plane train) {food water} foo bar';
a.match(/[a-zA-Z0-9\[\]\(\){}]+/g).map(function (s) { return s.replace(/[\[\]\(\)\{\}]/, ''); });
["apples", "carrots", "car", "plane", "train", "food", "water", "foo", "bar"]

Alternatively:

a.split(/\s+(?![^\[]*\]|[^(]*\)|[^\{]*})/)

Produces:

["[apples carrots]", "(car plane train)", "{food water}", "foo", "bar"]

Answer 2

Split on whitespace followed by a positive look-ahead that checks if next bracket char (if any) is an open one (or end of input):

\s+(?=[^\])}]*([\[({]|$))