Regular Expression matching biggest possible

ruby-talk
1

Hi,

I would like to remove comments from a JavaScript file with a Ruby
script. I discovered that my regular expression matching seems to match
the biggest possible substring.

def show_regexp(a,re)
  if a =~ re
    "#{$`}<<#{$&}>>#{$'}"
  else
    "no match"
  end
end
puts show_regexp("/* some comment */ some code /* some other comment
*/", /\/\*[\w\W]*\*\//)

This outputs

<</* some comment */ some code /* some other comment */>>

and I was hoping for it to find the individual comments.

<</* some comment */>> some code <</* some other comment */>>

What should my regular expression be?

Thanks,
Peter

2

You can make a regexp non greedy with a ?, that is

/\/\*[\w\W]*?\*\//
                ^

3

petermichaux@gmail.com wrote:

Hi,

I would like to remove comments from a JavaScript file with a Ruby
script. I discovered that my regular expression matching seems to match
the biggest possible substring.

Wow, I only had to wait 20 minutes before posting (or you could have checked the regexp madness thread).
Seems today is greedy regexp day :slight_smile:
V.-

···

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4

Chris Alfeld wrote:

You can make a regexp non greedy with a ?, that is

/\/\*[\w\W]*?\*\//

Thanks Chris,

Now I can easily find what i need in the manual:)

Peter