# Reusing chunks of code

**URL:** <https://www.ruby-forum.com/t/reusing-chunks-of-code/127002>\
**Category:** Ruby\
**Created:** [January 24, 2008, 2:34am UTC](https://www.ruby-forum.com/t/reusing-chunks-of-code/127002 "2008-01-24T02:34:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jmaenpaa](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9de053/32.png) [@jmaenpaa](https://www.ruby-forum.com/u/jmaenpaa)\
**Post date:** [January 24, 2008, 2:34am UTC](https://www.ruby-forum.com/t/reusing-chunks-of-code/127002/1 "2008-01-24T02:34:14Z")

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Hi guys,

I wanted to avoid using the word “block” as it’s such a key word in  
Ruby.  
I’m performing the same test twice here and there must be a way to  
reuse it…  
=begin  
Mon Jan 21 12:51:19 GMT 2008  
simple plays with dirs  
=end

# create a “singleton object”

testobj = Object.new

# play with the object - just a start 😉

def testobj.homePlay  
startDir = Dir.pwd  
p “current dir is #{startDir}”  
puts “Dir.getwd == Dir.pwd” if Dir.getwd == Dir.pwd

# check for ~/

if Dir.exist?("#{ENV[“HOME”]}")  
p “changing to ~/”  
else  
p “cannot find your home dir. STOP!”  
exit  
end

Dir.chdir

# have we changed directory from where we started?

if Dir.pwd == startDir  
p “current dir is still #{startDir}. pwd not changed ;-)”  
else  
p “pwd has changed to Dir.pwd”  
end

print “file listing of your home dir…\n\n”

p Dir.entries(".").sort # \<\< this an array  
print “\n\nlisting …/ \n\n”  
Dir.foreach("…") {|x| p x}

end

# end of method testobj.dirPlay

def testobj.procPlay  
px = “/proc/”  
if Dir.exist?("#{px}")  
p “#{px} dir found - continue”  
else  
p “#{px} not found - STOP!”  
exit  
end  
end

# send message to object

testobj.homePlay  
testobj.procPlay

**END**  
The question is how to reuse the “testing if directory exists chunk of  
code”? I’m still thinking procedurally I guess.  
Regards,

John M.  
MSc (DIC)  
+44 7739 171 531

---

<div class="post-metadata">

**Author:** ![jmaenpaa](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9de053/32.png) [@jmaenpaa](https://www.ruby-forum.com/u/jmaenpaa)\
**Post date:** [January 24, 2008, 3:18am UTC](https://www.ruby-forum.com/t/reusing-chunks-of-code/127002/2 "2008-01-24T03:18:07Z")

</div>

John M. wrote:

> Hi guys,
> 
> I wanted to avoid using the word “block” as it’s such a key word in  
> Ruby.  
> I’m performing the same test twice here and there must be a way to  
> reuse it…  
> =begin  
> Mon Jan 21 12:51:19 GMT 2008  
> simple plays with dirs  
> =end
> 
> # create a “singleton object”
> 
> testobj = Object.new
> 
> # play with the object - just a start 😉
> 
> def testobj.homePlay  
> startDir = Dir.pwd  
> p “current dir is #{startDir}”  
> puts “Dir.getwd == Dir.pwd” if Dir.getwd == Dir.pwd
> 
> # check for ~/
> 
> if Dir.exist?("#{ENV[“HOME”]}")  
> p “changing to ~/”  
> else  
> p “cannot find your home dir. STOP!”  
> exit  
> end
> 
> Dir.chdir
> 
> # have we changed directory from where we started?
> 
> if Dir.pwd == startDir  
> p “current dir is still #{startDir}. pwd not changed ;-)”  
> else  
> p “pwd has changed to Dir.pwd”  
> end
> 
> print “file listing of your home dir…\n\n”
> 
> p Dir.entries(".").sort # \<\< this an array  
> print “\n\nlisting …/ \n\n”  
> Dir.foreach("…") {|x| p x}
> 
> end
> 
> # end of method testobj.dirPlay
> 
> def testobj.procPlay  
> px = “/proc/”  
> if Dir.exist?("#{px}")  
> p “#{px} dir found - continue”  
> else  
> p “#{px} not found - STOP!”  
> exit  
> end  
> end
> 
> # send message to object
> 
> testobj.homePlay  
> testobj.procPlay
> 
> **END**  
> The question is how to reuse the “testing if directory exists chunk of  
> code”? I’m still thinking procedurally I guess.  
> Regards,
> 
> John M.  
> MSc (DIC)  
> +44 7739 171 531

> puts “Dir.getwd == Dir.pwd” if Dir.getwd == Dir.pwd

According to my book, getwd() and pwd() are the same method.

> if Dir.exist?("#{ENV[“HOME”]}")

Dir.exist? I don’t have that method. Is it new?

> The question is how to reuse the “testing if directory exists chunk of  
> code”? I’m still thinking procedurally I guess.

Do you mean this part:

> if Dir.exist?("#{ENV[“HOME”]}")  
> p “changing to ~/”  
> else  
> p “cannot find your home dir. STOP!”  
> exit  
> end

You could write:

def check\_dir(some\_str)  
if Dir.exist?(some\_str)  
p “changing to ~/”  
else  
p “cannot find your home dir. STOP!”  
exit  
end  
end

but that isn’t very general since you hardcoded the message to output.  
You could pass two messages in as arguments, but really what does the  
output message have to do with checking whether the dir exists? So that  
leaves you with something like this:

def check\_dir(some\_str)  
return Dir.exist?(some\_str)  
end

And you could write:

if check\_dir(“some dir”)  
puts ‘yep’  
else  
puts ‘nope’  
end

But that code just wraps a definition around a ruby method, so why not  
just call the method directly–like you did in the first place:

if Dir.exist?(“some dir”)  
puts ‘yep’  
else  
puts ‘nope’  
end