Calculator parse user input using regex

Question

Have the next regex /+|-^[(-], which I use in String.split(regex) method.

I want to split in situations when there is plus or minus, but if it's minus then don't split if before him there is opening parentheses.

Correct example: toDollar(-45euro)-$30 ----> { toDollar(-45euro) , $30 }.

So my regex doesn't follow this rule, how to modify it ?

regex101.com/r/lS5tT3/33 is this a valid input?
– vks
Commented Sep 25, 2014 at 17:42 — vks, Commented Sep 25, 2014 at 17:42

Casimir et Hippolyte · Accepted Answer · 2014-09-25 16:59:02Z

2

You are looking for is a negative lookbehind:

\\+|(?<!\\()-

(?<!...) is the lookbehind and means "not preceded by ..."

answered Sep 25, 2014 at 16:59

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