[Code] wrapping operations

[Dan Rathbun]

ALWAYS use a begin .. rescue .. end block for your operation.

If an error occurs, the operation can be aborted, and (hopefully,) prevent corruption of the model.

begin
  op_name = "My Operation"
  model.start_operation( op_name )
    #
    ### indented code statements here
    #
  model.commit_operation
rescue => e
  model.abort_operation
  puts("Error #<#{e.class.name};#{e.message}.>")
  puts(e.backtrace) if $VERBOSE
else
  #
  # Do code here ONLY if NO errors occur.
  #
ensure
  #
  # ALWAYS do code here errors or not.
  #
end

[jolran]

Thanks.

/Joel

[Francis Mc Shane]

Dan,
thanks for this. It works. I don't know why though!
Best,
Francis

[Dan Rathbun]

@francis mc shane said:

Dan,
thanks for this. It works. I don't know why though!

File: exceptions.rdoc [Ruby 2.0.0]

(ruby-doc.org)

Ya should probably read the docs on page
http://ruby-doc.org/core-2.0.0/index.html
from "doc/syntax.rdoc" on down. There is only 11.

[MSP_Greg]

One can also wrap Dan's code in a method

def self.operation(opName, procElse = nil, procEnsure = nil)
  if (block_given? && String === opName)
    am = Sketchup.active_model
    begin
      am.start_operation(opName, true)
      yield
      am.commit_operation
    rescue => e
      am.abort_operation
      puts("Error operation block #<#{e.class.name};#{e.message}.>")
      puts(e.backtrace) if $VERBOSE
    else
      procElse.call()   if (Proc === procElse)
    ensure
      procEnsure.call() if (Proc === procEnsure)
    end
  else
    raise "Error operation parameters - No block given or opName not a String!"
  end
end

# call by
# operation("My operation") { operation block }

Note that if either procElse and procEnsure are used, they should probably be lambdas. One should also be careful about return statements in the block passed to the method.

BTW, I'll use snake case for methods, maybe not variables...

Greg