Getting functions content with regex

Question

I'm trying to get the functions from an input string by using regular expressions.

So far, I managed to get the JavaScript kind of function declarations with the following regex:

/(\b(f|F)unction(.*?)\((.*?)\)\s*\{)/g

Which when applied like this, will return me whole declaration on the first index:

var re = /(\b(f|F)unction(.*?)\((.*?)\)\s*\{)/g;

while ((m = re.exec(text)) !== null) {
    //m[0] contains the function declaration
    declarations.push(m[0]);
}

Now, I would like to get in the returned match, the whole content of each of the functions so I can work with it later on (removed it, wrap it...)

I haven't managed to find a regext to do so, so far, I got this:

(\b(f|F)unction(.*?)\((.*?)\)\s*\{)(.*?|\n)*\}

But of course, it catches the first closing bracket } instead of the one at the end of each of the functions.

Any idea of how to get the closing } of each function?

Why are you trying to do this? Perhaps there's a better way to achieve your end goal? — James Montagne, May 05 '15 at 14:50
check this http://stackoverflow.com/questions/13952870/regular-expression-to-get-parameter-list-from-function-definition — carlos a., May 05 '15 at 14:51
This is impossible to do with regex alone since regular expressions contain no capacity for counting, which is what you would need to match brackets. — Mike Cluck, May 05 '15 at 14:51
You should use a parser like http://lisperator.net/uglifyjs/parser — Kos, May 05 '15 at 14:57
The why is always relevant, because it helps avoid wasting time on [XY-Problems](http://meta.stackexchange.com/questions/66377/what-is-the-xy-problem). — Richard, May 05 '15 at 14:58

Richard · Accepted Answer · 2015-05-05T14:59:16.023

4

Any idea of how to get the closing } of each function?

This will be very hard with a regex. Because the function body can include any number of possibly nested brace pairs. And then consider strings containing unmatched braces in the function body.

To parse a non-regular language you need something more powerful than regular expressions: a parser for that language.

(Some regex variants have some ability to matched paired characters, but firstly JavaScript's regex engine isn't one; and secondly then there are those strings….)

edited May 05 '15 at 14:59

answered May 05 '15 at 14:53

Richard

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Agree, but the string trap is not so difficult to avoid, on the other hand a function that contains a regex non enclosed in a string as in javascript... – Casimir et Hippolyte May 05 '15 at 15:23

Getting functions content with regex

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