Efficient way to catch & continue on exception

ruby-talk
1

I have the following :

hs = {}
hs.default = nil
hs['name3'] = command3
hs['name2'] = command2
hs['name1'] = command1

Where command* are methods that can fail and raise an exception. The
only way I know to deal with this is :

begin
hs['name3'] = command3
rescue
end
begin
hs['name2'] = command2
rescue
end
begin
hs['name1'] = command1
rescue
end

Is there a more compact/nicer of dealing with this. Because I have about
10-15 of these in a row in my code that I unfortunately can't change to
anything better.

What I would really want is something that if an exception is raised to
skip that line and just continue with the next line.

···

--
Posted via http://www.ruby-forum.com/.

2

rbx-head :001 > def throw
rbx-head :002?> throw "hey"
rbx-head :003?> end
=> #<Rubinius::CompiledMethod throw file=(irb)>
rbx-head :004 > throw rescue puts "rescued"
rescued
=> nil

3
···

On Wed, Oct 19, 2011 at 11:49 AM, Kassym Dorsel <k.dorsel@gmail.com> wrote:

begin
hs['name3'] = command3
rescue
end
begin
hs['name2'] = command2
rescue
end
begin
hs['name1'] = command1
rescue
end

Is there a more compact/nicer of dealing with this. Because I have about
10-15 of these in a row

--
Carina

4

That could work. Just one last thing to solve.

assignments = {:name1=>"arr.grep(/Input:.*/)[0][6..-1]"}

assignments.each_pair {|k,v| hs[k] = how do I call this command
associated with :name1}

.method(:method).call(arguments) and .send("method") only seem to work
for single methods and not combined ones like the example above.

···

--
Posted via http://www.ruby-forum.com/.

5

A couple options:

hs = {}
hs['name3'] = (command3 rescue nil)
hs['name2'] = (command2 rescue nil)
hs['name1'] = (command1 rescue nil)

Or how about:

module Capture
  def capture(key)
    self[key] = yield
  rescue
    self[key] = nil
  end
end

hs = {}.extend Capture
hs.capture('name3') { command3 }
hs.capture('name2') { command2 }
hs.capture('name1') { command1 }

···

On Oct 19, 2011, at 2:49 PM, Kassym Dorsel wrote:

I have the following :

hs = {}
hs.default = nil
hs['name3'] = command3
hs['name2'] = command2
hs['name1'] = command1

Where command* are methods that can fail and raise an exception. The
only way I know to deal with this is :

6

C. Zona wrote in post #1027457:

Something like that, but I can't use a loop. Each command and each hash
entry name is different and have to be hard coded.

···

--
Posted via http://www.ruby-forum.com/.

7

Well, you can do this, but remember you have to deal with exceptions thrown in your proc.

ruby-1.9.2-p290 :001 > hs = {}
  => {}
ruby-1.9.2-p290 :002 > target = []
  => []
ruby-1.9.2-p290 :003 > assignments = {:name1=>Proc.new {|arr| foo = arr.grep(/Input:.*/)[0]; foo && foo[6..-1] || nil}}
  => {:name1=>#<Proc:0x000000009c72a0@(irb):3>}
ruby-1.9.2-p290 :004 > assignments.each_pair {|k,v| hs[k] = v.call(target)}
  => {:name1=>#<Proc:0x000000009c72a0@(irb):3>}
ruby-1.9.2-p290 :005 > hs
  => {:name1=>nil}

The proc in assignments could be something like this if you didn't want the foo (you can use tap or something to debug inside the proc if needs be)

ruby-1.9.2-p290 :006 > assignments = {:name1=>Proc.new {|arr| arr.grep(/Input:.*/)[0][6..-1] rescue nil}}
=> {:name1=>#<Proc:0x00000000872f58@(irb):6>}
ruby-1.9.2-p290 :007 > assignments.each_pair {|k,v| hs[k] = v.call(target)}
  => {:name1=>#<Proc:0x00000000872f58@(irb):6>}
ruby-1.9.2-p290 :008 > hs
  => {:name1=>nil}

Does that help?

Sam

···

On 20/10/11 09:38, Kassym Dorsel wrote:

That could work. Just one last thing to solve.

assignments = {:name1=>"arr.grep(/Input:.*/)[0][6..-1]"}

assignments.each_pair {|k,v| hs[k] = how do I call this command
associated with :name1}

  .method(:method).call(arguments) and .send("method") only seem to work
for single methods and not combined ones like the example above.

8

C. Zona wrote in post #1027457:
http://stackoverflow.com/questions/2624835/ruby-continue-a-loop-after-catching-an-exception

Something like that, but I can't use a loop. Each command and each hash
entry name is different and have to be hard coded.

Do they need to be hard coded? Can you configure it with a hash of name to command mapping, and then simply iterate the hash with each_pair?

> irb
ruby-1.9.2-p290 :001 > hs = {}
  => {}
ruby-1.9.2-p290 :002 > hs.default = nil
  => nil
ruby-1.9.2-p290 :003 > def command1; 'command1_result';end
  => nil
ruby-1.9.2-p290 :004 > def command2; 'command2_result';end
  => nil
ruby-1.9.2-p290 :005 > def command3; 'command3_result';end
  => nil
ruby-1.9.2-p290 :006 > assignments = {:name1=>:command1, :name2=>:command2, :name3=>:command3}
  => {:name1=>:command1, :name2=>:command2, :name3=>:command3}
ruby-1.9.2-p290 :007 > assignments.each_pair {|k,v| hs[k] = method(v).call}
  => {:name1=>:command1, :name2=>:command2, :name3=>:command3}
ruby-1.9.2-p290 :008 > hs
  => {:name1=>"command1_result", :name2=>"command2_result", :name3=>"command3_result"}

Then you have your loop.

Sam

···

On 20/10/11 08:45, Kassym Dorsel wrote: