Regular expression object question

ruby-talk
1

Hi all,

Is there a way to add a new regex to an existing regular expression
object?

In other words, say I start with a pattern I want to match:

re = /xyz/

But later, I decide that I want to also match “abc”. As it stands now,
I have to create a new regex object for that. Thus:

re2 = /abc/

This could go on indefinitely, so simply doing this could quickly become
cumbersome:

if re.match(string) || re2.match(string)…

Thus, what I would like is a way to “push” a new regex onto an old one
(i.e. add an “and” or “or”).

example:

re = /xyz/
re.push("|abc") -> re is now /xyz|abc/

Thoughts? Should I just create my own subclass that does this and shut
up?

Regards,

Dan

2

Hi,

Well, if your regular expression is not very complicated, you can
simply use the Regexp “new()” and “source()” methods:

re = Regexp.new ('xyz')
re = Regexp.new (re.source + 'abc')
....

Regards,

Bill

···

==========================================================================
Daniel Berger djberge@v55host11.interprise.com wrote:

Hi all,

Is there a way to add a new regex to an existing regular expression
object?

In other words, say I start with a pattern I want to match:

re = /xyz/

But later, I decide that I want to also match “abc”. As it stands now,
I have to create a new regex object for that. Thus:

re2 = /abc/

This could go on indefinitely, so simply doing this could quickly become
cumbersome:

if re.match(string) || re2.match(string)…

Thus, what I would like is a way to “push” a new regex onto an old one
(i.e. add an “and” or “or”).

example:

re = /xyz/
re.push(“|abc”) → re is now /xyz|abc/

Thoughts? Should I just create my own subclass that does this and shut
up?

Regards,

Dan

3

Hello Daniel,

Tuesday, September 24, 2002, 7:56:55 PM, you wrote:

re = /xyz/

re2 = /abc/

if re.match(string) || re2.match(string)…

see eregex.rb. more effective approach:

class Array
def =~ (str)
find {|re| re =~ str}
}
}

list = [/abc/, /xyz/]
list << /def/ << /tuv/
print ‘Yes!’ if list =~ ‘qwerty’

btw, you don’t need to subclass Regexp just to implement one it’s
operator :wink:

···

–
Best regards,
Bulat mailto:bulatz@integ.ru