Question on redefining the File.join mechanism


#1

I’m running Ruby over WindowsXP-Pro/SP2. So I wanted File.join to use
backslash.

I tried:

class WFile < File
def join(arg1, arg2)
super.join(arg1, arg2).gsub(///, ‘\’)
end
end

but WFile.join(s1,s2) didn’t work. My question is why?

BTW, I don’t want to start or enter into a debate about the wisdom
nor aesthetics of this approach.

Also, I got the File.wjoin to work (using the code below), so I’m
happy. I just want to learn why my first idea is flawed.

class File # Join with a backslash rather than a forward slash
def File.wjoin(arg1, arg2)
join(arg1, arg2).gsub(///, ‘\’)
end
end

Thanks in Advance,
Richard


#2

I just want to learn why my first idea is flawed.

I believe one culprit is probably
super.join

In fact, I never saw super.join, only super() on something.

Where did you see super.something ?


#3

In fact, I never saw super.join, only super() on something.

Where did you see super.something ?

Must have been in a dream :slight_smile: Please see my solution in my reply to
Robert.

Thanks for your response,
Richard


#4

2009/5/12 RichardOnRails removed_email_address@domain.invalid:

I’m running Ruby over WindowsXP-Pro/SP2. So I wanted File.join to use
backslash.

I tried:

class WFile < File
def join(arg1, arg2)
super.join(arg1, arg2).gsub(///, ‘\’)

That line should look like one of these variants:

super.gsub(///, ‘\’)
super(arg1, arg2).gsub(///, ‘\’)

However, since join is a class method you would want to define it as
class method in WFile.

irb(main):001:0> class WFile < File
irb(main):002:1> def self.join(*a) super.gsub(%r{/}, ‘\\’) end
irb(main):003:1> end
=> nil
irb(main):004:0> WFile.join “foo”, “bar”, “baz”
=> “foo\bar\baz”
irb(main):005:0>

class File # Join with a backslash rather than a forward slash
def File.wjoin(arg1, arg2)
join(arg1, arg2).gsub(///, ‘\’)
end
end

Another however: since you are defining a single method only the
question is whether it warrants a comlete class. Why not just define
wjoin in class File or simply override File’s definition, e.g.

def File.join(*a)
a.join ‘\’
end

Kind regards

robert


#5

On May 12, 10:34 am, Robert K. removed_email_address@domain.invalid wrote:

irb(main):003:1> end

but WFile.join(s1,s2) didn’t work. My question is why?
end
Kind regards

robert


remember.guy do |as, often| as.you_can - without endhttp://blog.rubybestpractices.com/

Hi Robert,

Thanks to Marc in the previous post and to you, my head cleared and
following is the solution I sought, which is a style that suits my
aesthetics :slight_smile: :

class WFile
def WFile.join(arg1, arg2)
File.join(arg1, arg2).gsub(///, ‘\’)
end
end

puts WFile.join(‘foo’, ‘bar’) # => foo\bar

Ya gotta love comp.lang.ruby.

Best wishes,
Richard


#6

On 13.05.2009 08:31, RichardOnRails wrote:

Now I see that you’ve reduced the matter to Array#join, so I could
simple write:

[‘foo’, ‘bar’].join ‘\’ # => foo\bar,

Exactly.

but wrapping in a 3-liner like yours probably simplifies invocation.
I’ll think about it some more. Your 3-liner looks like one more “best
practice”, which site I just visited.

Thanks for education in Ruby elegance.

You’re welcome! Just another remark: it’s been a while that I used the
Windows version of Ruby (I work mostly on cygwin and Linux) but as far
as I remember if you need those file names only internally (i.e. in the
Ruby program) then the regular File.join will do as you can use forward
and backward slashes.

Kind regards

robert


#7

… then the regular File.join will do as you can use
forward and backward slashes.

That has been my experience, but I don’t like relying on that and
finally decided to fix it to my liking.

Thanks again and best wishes,
Richard


#8

On May 12, 10:34 am, Robert K. removed_email_address@domain.invalid wrote:

irb(main):003:1> end

but WFile.join(s1,s2) didn’t work. My question is why?
end
Kind regards

robert


remember.guy do |as, often| as.you_can - without endhttp://blog.rubybestpractices.com/

Hi, again, Robert,

Just a little follow-up. When I first read your response, I grabbed
your “class method” observation and ran with it. I saw your
additional 3-liner, but didn’t understand it at first glance.

Now I see that you’ve reduced the matter to Array#join, so I could
simple write:

[‘foo’, ‘bar’].join ‘\’ # => foo\bar,

but wrapping in a 3-liner like yours probably simplifies invocation.
I’ll think about it some more. Your 3-liner looks like one more “best
practice”, which site I just visited.

Thanks for education in Ruby elegance.

Best wishes,
Richard