My stupid code

Ruby
1

Hi,
I’m trying to write a small ruby script which accepts:

  1. Input : File or $stdin
  2. Output : File or $stdout

This is my stupid code:
#---------------------------------------------------------
def do_some_thing(str)

do some things over str

end

f_in = ARGV[0]
f_out = ARGV[1]
if f_out==nil
fout = File.open(f_out,“w”)
end

if f_in==nil
$stdin.each { |line|
if f_out==nil
print do_some_thing(line)
else
fout.print do_some_thing(line)
end
}
else
File.open(f_in,“r”).each {|line|
if f_out==nil
print do_some_thing(line)
else
fout.print do_some_thing(line)
end
}
end
fout.close if f_out!=nil
#--------------------------------------------------------------------
Don’t laugh at me :slight_smile: I’m learning Ruby so I would like to hear from
you a better way to write this small code.

Thank you in advance and Happy New Year !

2

I’m trying to write a small ruby script which accepts:

  1. Input : File or $stdin
  2. Output : File or $stdout

Abstraction is the keyword. Put the decision to open a file or
stdin or stdout in a a method on the class File and put that
code in a library. That keeps your application clean and
simple.

gegroet,
Erik V. - http://www.erikveen.dds.nl/

LIBRARY

class File
def self.open_std(file, mode=“r”, *rest, &block)
if file.nil?
if block_given?
block.call(mode.include?(“r”) ? $stdin : $stdout)
else
mode.include?(“r”) ? $stdin : $stdout
end
else
File.open(file, mode, *rest, &block)
end
end
end

APPLICATION

require “your_library”

def do_some_thing(str)

do some things over str

str.upcase
end

File.open_std(ARGV.shift, “r”) do |f_in|
File.open_std(ARGV.shift, “w”) do |f_out|
f_in.each do |line|
f_out.puts do_some_thing(line)
end
end
end

3

unknown wrote:

Hi,
I’m trying to write a small ruby script which accepts:

  1. Input : File or $stdin
  2. Output : File or $stdout

This is my stupid code:
#---------------------------------------------------------
def do_some_thing(str)

do some things over str

end

f_in = ARGV[0]
f_out = ARGV[1]
if f_out==nil
fout = File.open(f_out,“w”)
end

if f_in==nil
$stdin.each { |line|
if f_out==nil
print do_some_thing(line)
else
fout.print do_some_thing(line)
end
}
else
File.open(f_in,“r”).each {|line|
if f_out==nil
print do_some_thing(line)
else
fout.print do_some_thing(line)
end
}
end
fout.close if f_out!=nil

fin = ARGV[0] ? File.open(ARGV[0],‘r’) : $stdin
fout = ARGV[1] ? File.open(ARGV[1], ‘w’) : $stdin
fin.each_line do |line|
fout.print do_some_thing(line)
end

Or (hides File.open errors):
fin = File.open(ARGV[0],‘r’) rescue $stdin
fout = File.open(ARGV[1], ‘w’) rescue $stdout
fin.each_line do |line|
fout.print do_some_thing(line)
end

4

Erik V. wrote:

I’m trying to write a small ruby script which accepts:

  1. Input : File or $stdin
  2. Output : File or $stdout

Abstraction is the keyword. Put the decision to open a file or
stdin or stdout in a a method on the class File and put that
code in a library. That keeps your application clean and
simple.

I do not think that tinkering with the core classes is a good idea for
problems as simple as this.

5

fin = File.open(ARGV[0],‘r’) rescue $stdin
fout = File.open(ARGV[1], ‘w’) rescue $stdout
fin.each_line do |line|
fout.print do_some_thing(line)
end

You should close an IO stream, when it is a file.

gegroet,
Erik V. - http://www.erikveen.dds.nl/

6

I do not think that tinkering with the core classes is a good
idea for problems as simple as this.

Make it a new class, instead of “reusing” a core class… :slight_smile:

The point is that the question “use a file or std stream?” is
asked so often, that it’s worth pushing the code down into the
language.

“Enrich the language, so the applications are small.”

gegroet,
Erik V. - http://www.erikveen.dds.nl/

7

Thank you for your solution.

Dale Farnsworth has also same solution (emailed to me).

Thank you again!

8

Thank you but I’m not yet familar with class/method notions :slight_smile:
So I’ll return to your solution later, when I learned a little more
than actual.

Regards,

9

On 12/31/05, [email protected] [email protected] wrote:

Hi,
I’m trying to write a small ruby script which accepts:

  1. Input : File or $stdin
  2. Output : File or $stdout

in_file, out_file = ARGV
input = in_file ? File.open(in_file) : $stdin
output = out_file ? File.open(out_file,‘w’) : $stdout

input.each_line{|line|
output.print do_some_thing(line)
}

input.close
output.close_write
output.close if output.is_a? File

Cheers,
Ilmari