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grep backreferencing question

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# 8  
Old 10-19-2010
Well, C legality is a whole lot more than a grep! Is cc or CC making it hard to decipher?

I recommend never declaring more than 1 variable on a line. It facilitates diff and diff3 use. It gives you a distinct line number for every variable in error.
# 9  
Old 10-19-2010
It works even if I remove all the \<\> from the above code. Can you explain how?
# 10  
Old 10-19-2010
Quote:
Originally Posted by prasanna1157
>>>> Thanks lot. The only problem with the above is, it matches illegal declarations also.

like, int a,b,,b; int a,b,b,;

---------- Post updated at 02:20 PM ---------- Previous update was at 02:19 PM ----------




>>> Thanks lot. This one matches illegal declarations too.

like, int a,b,,b; int a,b,b,;
That wasn't part of your problem statement, was it? Anyway,
Code:
grep -E 'int .*([^,]+),.*\1[,\;]|int .*,[,\;]' infile

Last edited by Scrutinizer; 10-19-2010 at 05:06 PM..
# 11  
Old 10-19-2010
Without the \<\>, b matches bb.
# 12  
Old 10-19-2010
Thanks.

---------- Post updated at 02:59 PM ---------- Previous update was at 02:56 PM ----------
Quote:
Originally Posted by Scrutinizer
That wasn't part of your problem statement, was it? Anyway,
Code:
grep -E 'int .*([^,]+),.*\1[,\;]|int .*,[,\;]' infile

Code:
grep 'int .*\([^,][^,]*\),.*\1[,\;]\|int .*,[,\;]' infile

Oh, sorry. Yes, I did not state it initially.

One more question, the .* makes it match anything. But can I match only valid declarations? That is, the variables should start with alpha, can have only alphabets and numbers. Let's assume lowercase only. How do you tweak the above to check for that?

Thanks a lot.

---------- Post updated at 03:01 PM ---------- Previous update was at 02:59 PM ----------
Quote:
Originally Posted by DGPickett
Well, C legality is a whole lot more than a grep! Is cc or CC making it hard to decipher?

I recommend never declaring more than 1 variable on a line. It facilitates diff and diff3 use. It gives you a distinct line number for every variable in error.
Thanks.
So, can we not check for illegal declarations using the regex?
# 13  
Old 10-19-2010
Quote:
Originally Posted by prasanna1157
Thanks.

Oh, sorry. Yes, I did not state it initially.

One more question, the .* makes it match anything. But can I match only valid declarations? That is, the variables should start with alpha, can have only alphabets and numbers. Let's assume lowercase only. How do you tweak the above to check for that?
Hi, no the .* will not match anything, since they are embedded in context. What is your additional question? I think you question about back references is answered. If so, it may be better to start a new topic.
# 14  
Old 10-19-2010
Wrong comes in so many flavors, like integral calculus. Even right has a lot of flavors. First there are the datatypes, then the commas, the initializations, typedefs, unions, structs, Classes, code, continued lines, includes, macros.

Why not cc -c ? I hope it knows enough to catch that. There may even be c verification tools out there. Ever try lint?
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