Extracting portion of a file within braces using regular expression - regex

Question

I have a file which is of the following form :
some text
some more text
. . .
. . .
data {
1 2 3 5 yes 10
2 3 4 5 no 11
}
some text
some text
I want to extract the data portion of the file using regular expression using the following procedure:
proc ExtractData {fileName} {
set sgd [open $fileName r]
set sgdContents [read $sgd]
regexp "data \\{(?.*)\\}" $sgdContents -> data
puts $data
}
But this is giving the following error:
couldn't compile regular expression pattern: quantifier operand invalid
I am not able figure out what is wrong with regular expression. Any help would be highly appreciated.

Answer 1

Use this regular expression
regexp {data \{(.*)\}} $sgdContents wholematch submatch
puts $submatch
wholematch matches the entire pattern. In your case it is
data {
1 2 3 5 yes 10
2 3 4 5 no 11
}
And submatch matches only the content inside braces like below:
1 2 3 5 yes 10
2 3 4 5 no 11

Answer 2

The following regexp line works
regexp "data \\{\\\n(.*?)\\\n\\s*\\}" $sgdContents -> data
The only major thing wrong with the original regular expression was misplacement of the non-greedy match indicator (?), which directs the regular expression engine to stop matching as soon as first match is found.