Stop processing rest of file?

[thomthom]

When Ruby load a file, via require or load, is it possible to stop it from loading the rest if a certain condition occurs?

I'd like to make a check for TT_Lib2 when my plugins load - and if it's not installed a message is presented to the user and the rest of the plugin should not be loaded as it won't work. I want to avoid raising an error as that makes SU halt the loading and display an error dialog - which also jumbles toolbars etc.
exit! trashes SketchUp.

[Dan Rathbun]

Have you been looking over my shoulder ??

I was working on just this thang earlier in the week.
I think I came to the conclusion, that the best implementation, is to create gloabal methods (an extension to the Kernel mixin module.)

As far as load() goes.. there's no help, as that is always supposed to load regardless, and does not check the $LOADED_FEATURES array.

Let me go back and look at what I was doing, and think a bit more.

One thing I know I must do, is implement a global hash, called $LOAD_ERRORS (and an Array: $LOAD_ERROR_FILES,) that hold information when a script loading error occurs.

Then we can skip the crappy "Load error" dialog Google made. Wait until the end of the startup cycle, and display a Error GUI dialog, that can go back and look at any of the loading errors that occured. Likely this would be a WebDialog. It'd be nice to click a button a write to a logfile. Hilite a certain error, click a button and create a report to send to the author, or post as an attachemnt in the plugin's thread at SCF, or whereever.

[thomthom]

Regardless of load or require being used - I try to find a method that will stop ruby from processing the rest of the file - without killing SketchUp itself.

[Dan Rathbun]

In my prototype I also have a step that is only a comment at this point:

a) Display a webdialog here so the user can download the file(s).

b) call retry if download successful

[Dan Rathbun]

So far I am trying my best to NOT touch or override either require or load themselves.

[tbd]

have a separate loader.rb that checks if LIB exists and has functions required.
if yes, require/load rest of your code, if not ...

[Dan Rathbun]

Having to have yet ANOTHER file for each and every library or plugin package, is not what I am aiming at...

... besides that does not solve the idiot situation, trying to force a plugin to load, using load(), when require does not work.
I'm not sure there is a solution to the idiot syndrome anyway. I (personally,) would not give any support, or waste any time responding, to an idiot who does not let the plugin load the way it's supposed to.

[Dan Rathbun]

ThomThom, for now do something like:

module TT_FancyUtil

  # move require dependancy calls inside namespace
  require('TT/TT_Lib2') rescue raise(LoadError,'TT_Lib2')
  require('TT/TT_GUI') rescue raise(LoadError,'TT_GUI')

  # the rest of the module's code

# way down the bottom of the namespace block;
rescue LoadError => e

  case e.message
  when 'TT_Lib2'
    puts("LoadError; TT_Lib2 file is not present. .. blah blah blah...")
  when 'TT_GUI'
    puts("LoadError; TT_GUI file is not present. .. blah blah blah...")
  else
    puts("Error; #<#{e.class.name}; #{e.message}>")
    puts e.backtrace
  end

end # module

[thomthom]

@unknownuser said:

have a separate loader.rb that checks if LIB exists and has functions required.
if yes, require/load rest of your code, if not ...

Really don't want to use another file. Many of my plugins are self contained in a single file - apart from that they require TT_Lib. And I don't want to split it up just for this check.

[thomthom]

Found a way:

<span class="syntaxdefault">require </span><span class="syntaxstring">'sketchup.rb'<br /></span><span class="syntaxdefault">begin<br />  require </span><span class="syntaxstring">'TT_Lib2/core.rb'<br /></span><span class="syntaxdefault">rescue LoadError </span><span class="syntaxkeyword">=></span><span class="syntaxdefault"> e<br />  </span><span class="syntaxcomment"># meh!<br /></span><span class="syntaxdefault">end<br /><br />module MagicPlugin<br />  </span><span class="syntaxcomment"># Voodoo<br /></span><span class="syntaxdefault">end if defined</span><span class="syntaxkeyword">?(</span><span class="syntaxdefault"> TT</span><span class="syntaxkeyword">;;</span><span class="syntaxdefault">Lib </span><span class="syntaxkeyword">)<br /></span><span class="syntaxdefault"> </span>

[Dan Rathbun]

interesting!

Hmm ... I see rescue modifiers do not work with require(), for some reason ?

You could also do (if you did not want any module defined) ...

require 'sketchup.rb'
begin
  require 'TT_Lib2/core.rb'
rescue LoadError => e
  # meh!
else
  module MagicPlugin
    # Voodoo
  end
end# begin
 

[thomthom]

@dan rathbun said:

Hmm ... I see rescue modifiers do not work with require(), for some reason ?

What you mean? What modifiers?

[tbd]

statement modifiers = conditional statements onto the end of a normal statement

` name = first_name + last_name rescue "John Doe"

John Doe # if first_name and last_name are not defined`

[Dan Rathbun]

@thomthom said:

@dan rathbun said:

Hmm ... I see rescue modifiers do not work with require(), for some reason ?

What you mean? What modifiers?

The conditional keywords if and unless can be used in block position:
[ if| unless] ( expression)
statements
end

or modifier position:
statement [ if| unless] ( expression)

**rescue** can also be used in modifier poistion, but ... my attempt at this:
require('booboo.rb') rescue nil
... does NOT trap the LoadError (because LoadError < ScriptError < Exception, and rescue only traps RuntimeError and subclasses by default.)

For a one-liner, we must use semi-colons:
begin require('booboo.rb'); rescue Exception; nil; end