RegEx help (small)

[Bil Kleb]

I'm too dense to figure this one out today: The
second (and probably third) assertions fail...

require 'test/unit'

class String
def to_tex
gsub( /(?!\w)'(.*?)'/, '`\1\'' )
end
end

class StringTC < Test::Unit::TestCase
def test_single_quotation
assert_equal( "`single quotation'", "'single quotation'".to_tex )
assert_equal( "isn't fool'd", "isn't fool'd".to_tex )
assert_equal( "2' x 4'", "2' x 4'".to_tex )
end
end

Any help would be appreciated and probably evoke "duh!"

Thanks,

 

[ts]

B> gsub( /(?!\w)'(.*?)'/, '`\1\'' )

(?!) is a zero-width negative look-ahead


B> assert_equal( "isn't fool'd", "isn't fool'd".to_tex )

When the regexp engine is at this position (just before ')

"isn't fool'd"

^
|

* it look if it don't have a word character (\w) : this is true because the
first next character is '

* then it look if it has ' : it's true and it match



Guy Decoux

 

[Robert Klemme]

B> gsub( /(?!\w)'(.*?)'/, '`\1\'' )

(?!) is a zero-width negative look-ahead


B> assert_equal( "isn't fool'd", "isn't fool'd".to_tex )

When the regexp engine is at this position (just before ')

"isn't fool'd"

^
|

* it look if it don't have a word character (\w) : this is true because the
first next character is '

* then it look if it has ' : it's true and it match

These seem to work:

class String
def to_tex
gsub( /(?:\A|(?![\w']))'(.*?)'/, '`\\1\'' )
end
end => nil
"'single quotation'".to_tex

=> "`single quotation'"

class String
def to_tex
gsub( /'((?:[^\\']|\\.)*)'/, '`\\1\'' )
end
end => nil
"'single quotation'".to_tex

=> "`single quotation'"

But I dunno whether they fix all of your problems.

Kind regards

robert

 

[ts]

R> But I dunno whether they fix all of your problems.

You want Onigurama, with a zero-width negative look-behind (?<!)


Guy Decoux

 

[David A. Black]

Hi --

These seem to work:

gsub( /(?:\A|(?![\w']))'(.*?)'/, '`\\1\'' )
gsub( /'((?:[^\\']|\\.)*)'/, '`\\1\'' )

Also:

gsub( /(^|\W)'(.*?)'/, '\1`\2\'' )

passed the tests.


David