distinguishing a string with flex

Question

Hi,

I need to tokenize some strings which will be splitted of according to operators like = and !=. I was successful using regex until the string has != operator. In my case, string was seperated into two parts, which is expected but ! mark is in the left side even it is part of given operator. Therefore, I believe that regex is not suitable for it and I want to benefit from lex. Since I do not have enough knowledge and experience with lex, I am not sure whether it fits my work or not. Basically, I am trying to do replace the right hand side of the operators with actual values from other data. Do you people think that can it be helpful for my case?

Thanks.

Answer 1

Should you use lex? It depends how complex your language is. It's a very powerful tool, worth understanding (especially with yacc, or in Java you could use antlr or javacc).

public String[] split(String regex) does take a regex, not just a string. You could use the regex "!?=", which means zero or one ! followed by =. But the problem with using split is that it won't tell you what the actual delimiter was.

With what little info we have about your application, I'd be tempted to use regular expressions. There are lots of experts here on stackoverflow to help. A great place to start is the Java regex tutorial.

(Thanks to Falle1234 for picking up my mistake - now corrected.)