RCR: regex + regex
Feedback on the following suggestion for ruby: by default allow for adding regex's i.e. >> /foo/ + /bar/ => /foobar/ Thoughts? -r -- Posted via http://www.ruby-forum.com/.
rogerpack2005
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On Oct 26, 2009, at 5:13 PM, Roger Pack wrote: > Feedback on the following suggestion for ruby: > by default allow for adding regex's > > i.e. >>> /foo/ + /bar/ > => /foobar/ > > Thoughts? > -r > -- irb> a=/foo/ => /foo/ irb> b=/bar/ => /bar/ irb> class Regexp irb> def +(other) irb> self.class.new(self.to_s + other.to_s) irb> end irb> end => nil irb> a+b => /(?-mix:foo)(?-mix:bar)/ This is obviously too naive an implementation, but if we change a to / foo/i then I'd expect "Foobar" =~ (a+b) to be true (well, I mean 0, of course) and "fooBar" =~ (a+b) to be nil. What might be the corresponding * or - behaviors? It seems like a * b is closer to /(a)*(b)/ than anything else I could think of and that immediately implies: a + b becomes: /(a)+(b)/ rather than just /(a)(b)/ The fact that + is a meaningful character in a Regexp makes a universal meaning for it as an operation *on* regexps a bit ambiguous. -Rob Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com
Rob7461> What might be the corresponding * or - behaviors? It seems like > a * b > is closer to > /(a)*(b)/ That's what I'd guess for *, as well. > than anything else I could think of and that immediately implies: > a + b > becomes: > /(a)+(b)/ > rather than just /(a)(b)/ > > The fact that + is a meaningful character in a Regexp makes a > universal meaning for it as an operation *on* regexps a bit ambiguous. Yeah, or what | means or what not. I'd probably just stick with concatenation and not even *define* *. -r -- Posted via http://www.ruby-forum.com/.
2009/10/26 Roger Pack <rogerpack2005@gmail.com>:
>> What might be the corresponding * or - behaviors? It seems like
>> =A0 a * b
>> is closer to
>> =A0 /(a)*(b)/
>
>
> That's what I'd guess for *, as well.
>
>> than anything else I could think of and that immediately implies:
>> =A0 a + b
>> becomes:
>> =A0 /(a)+(b)/
>> rather than just /(a)(b)/
>>
>> The fact that + is a meaningful character in a Regexp makes a
>> universal meaning for it as an operation *on* regexps a bit ambiguous.
>
> Yeah, or what |
> means or what not. =A0I'd probably just stick with concatenation and not
> even *define* *.
You are aware that you can use string interpolation in regular
expressions, do you?
irb(main):001:0> a=3D/foo/
=3D> /foo/
irb(main):002:0> b=3D/bar/
=3D> /bar/
irb(main):003:0> x=3D/#{a}#{b}/
=3D> /(?-mix:foo)(?-mix:bar)/
Kind regards
robert
--=20
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/
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