Regular expression to align comments

Posted on 2013-12-12
Medium Priority
Last Modified: 2013-12-12
I have a huge file with c structures with comments that are not aligned like below.

 // Structure 1
   {    1 , //Comment 0
       "ABC",   // Comment 1
       { 480 , 440 },        // Comment 2
       { 2000 , 4000 , 0 , 0 , 0 , 0 },    // Comment 3
       { 800 , 400 , 800 , 4000 , 0 , 0 },               // Comment 4

I want to make it look like:
                                                                             // Structure 1
   {    1 ,                                                                 //Comment 0
       "ABC",                                                            // Comment 1
       { 480 , 440 },                                                 // Comment 2
       { 2000 , 4000 , 0 , 0 , 0 , 0 },                        // Comment 3
       { 800 , 400 , 800 , 4000 , 0 , 0 },                 // Comment 4

since the file is very large I don't want to do it manually... Any regular expression that can do this?  thank you.
Question by:ambuli
LVL 27

Expert Comment

ID: 39714902
Have you looked at Perltidy?  It might work for the purpose.
LVL 31

Assisted Solution

farzanj earned 1600 total points
ID: 39714921
Try something like

perl -pe 's{\s+//}{\t\t\t\t//}' filename

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This is very specific to the above code.

When you see your output is good, you can use -i to make changes to the file
LVL 32

Assisted Solution

serialband earned 400 total points
ID: 39714972
There's also several others more specifically designed for C, C++, Java style code.

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Author Comment

ID: 39714982
Thank you.  That works to some extent.  But, still tab introduces some problems.  How can I modify this so that I can say I want to move the comments to say column 50.
LVL 31

Expert Comment

ID: 39715156
Try this:

perl -ne 'm{(.*?)\s+(//.*)}; $s = ((50 - length($1)) > 0 ? 50-length($1):0); printf("%s%${s}s\n", $1, $2)' filename

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LVL 31

Accepted Solution

farzanj earned 1600 total points
ID: 39715201
Actually, the above one doesn't consider non matched lines.

Try this instead

perl -ne 'if(m{(.*?)\s*(//.*)}){$s = ((55 - length($1)) > 0 ? 55-length($1):0); printf("%s%${s}s\n", $1, $2)} else {print}' filename

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