Using Regex to find function containing a specific method or variable

Question

This is my first post on stackoverflow, so please be gentle with me...

I am still learning regex - mostly because I have finally discovered how useful they can be and this is in part through using Sublime Text 2. So this is Perl regex (I believe)

I have done searching on this and other sites but I am now genuinely stuck. Maybe I am trying to do something that can't be done

I would like to find a regex (pattern) that will let me find the function or method or procedure etc that contains a given variable or method call.

I have tried a number of expressions and they seem to get part of the way but not all the way. Particularly when searching in Javascript I pick up multiple function declarations instead of the one nearest to the call/variable that I am looking for.

for example: I am looking for the function that calls the method save data() I have learnt, from this excellent site that I can use (?s) to switch . to include newlines

function.*(?=(?s).*?savedata\(\))

however, that will find the first instance of the word function and then all the text unto and including savedata()

if there are multiple procedures then it will start at the next function and repeat until it gets to savedata() again

function(?s).*?savedata\(\) does something similar

I have tried asking it to ignore the second function (I believe) by using something like:

function(?s).*?(?:(?!function).*?)*savedata\(\)

But that doesn't work.

I have done some investigation with look forwards and look backwards but either I am doing it wrong (highly possible) or they are not the right thing.

In summary (I guess), how do I go backwards, from a given word to the nearest occurrence of a different word.

At the moment I am using this to search through some javascript files to try and understand the structure/calls etc but ultimately I am hoping to use on c# files and some vb.net files

Many thanks in advance

Thanks for the swift responses and sorry for not added an example block of code - which I will do now (modified but still sufficient to show the issue)

if I have a simple block of javascript like the following:

    function a_CellClickHandler(gridName, cellId, button){
        var stuffhappenshere;
        var and here;
        if(something or other){
            if (anothertest) {

                event.returnValue=false;
                event.cancelBubble=true;
                return true; 
            }
            else{
                event.returnValue=false;
                event.cancelBubble=true;
                return true;
            }
        } 
    }

    function a_DblClickHandler(gridName, cellId){
        var userRow = rowfromsomewhere;
        var userCell = cellfromsomewhereelse;
        //this will need to save the local data before allowing any inserts to ensure that they are inserted in the correct place
        if (checkforarangeofthings){
            if (differenttest) {
                InsSeqNum = insertnumbervalue;
                InsRowID = arow.getValue()
                blnWasInsert = true;
                blnWasDoubleClick = true;
                SaveData();      
            }
        }
    }

running the regex against this - including the second one that was identified as should be working Sublime Text 2 will select everything from the first function through to SaveData()

I would like to be able to get to just the dblClickHandler in this case - not both.

Hopefully this code snippet will add some clarity and sorry for not posting originally as I hoped a standard code file would suffice.

Answer 1

This regex will find every Javascript function containing the SaveData method:

(?<=[\r\n])([\t ]*+)function[^\r\n]*+[\r\n]++(?:(?!\1\})[^\r\n]*+[\r\n]++)*?[^\r\n]*?\bSaveData\(\)

It will match all the lines in the function up to, and including, the first line containing the SaveData method.

Caveat:

• The source code must have well-formed indentation for this to work, as the regex uses matching indentations to detect the end of functions.
• Will not match a function if it starts on the first line of the file.

Explanation:

(?<=[\r\n])                      Start at the beginning of a line
([\t ]*+)                        Capture the indentation of that line in Capture Group 1
function[^\r\n]*+[\r\n]++        Match the rest of the declaration line of the function
(?:(?!\1\})[^\r\n]*+[\r\n]++)*?  Match more lines (lazily) which are not the last line of the function, until: 
[^\r\n]*?\bSaveData\(\)          Match the first line of the function containing the SaveData method call

Note: The *+ and ++ are possessive quantifiers, only used to speed up execution.

EDIT: Fixed two minor problems with the regex.
EDIT: Fixed another minor problem with the regex.