Refactorings again: idea for library

Ruby
1

Hi all.

Here’s an idea stolen from [1] and [2].

Suppose we have a library. Suppose we’ve done some refactorings in it
(method or class renamed, class splitted into several, or joined, or…)

The task: change all client code in correspondence to library change.

The trick:

library/changelog.rb

module MyLibrary::Changelog
version(0.2.5) do
method_renamed [SomeClass, :method_a] => :method_b
method_removed [SomeClass, :old_method], “he was too old”
module_method_moved [SomeModule, :method_c] => OtherModule
class_renamed ClassA => ClassB
end
end

in code, which uses our library:

require ‘library’
require ‘library/changelog’ #can omit this if you’re not interested in
changes

s = SomeClass.new

s.method_a
#prints "Warning: method #method_a is renamed to #method_b. Called from
app.rb:10
#then calls s.method_b

s.old_method
#throws “Error: #old_method was removed because he was too old”
#? or prints warning and DOESN’T calls any method

SomeModule::method_c
#prints "Warning: method #method_c moved to OtherModule. Called from
app.rb:12
#then calls OtherModule::method_c

ClassA.new
#prints “Warning: ClassA renamed to ClassB. blah”
#then calls ClassB.new

the version(0.0.2) in example above can allow user to say
MyLibrary::ChangeLog.from_version = 0.2.1 #migrating from 0.2.1 to 0.2.5

and see only appropriate warnings.

Wha?

V.

1:
http://www.dogbiscuit.org/mdub/weblog/Tech/Programming/Ruby/RubyMethodRename
d
2: http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/49730

2

On Sep 26, 6:42 am, “Victor "Zverok" Shepelev”
[email protected] wrote:

s.method_a
app.rb:12
and see only appropriate warnings.

Wha?

It a very interesting idea. But I fear it would too hard to maintain
for anything but the smallest lib/app. I think it’s better to just to
have intermediary versions that add warnings to methods that are going
away soon (if possible).

T.

3

From: Trans [mailto:[email protected]]
Sent: Wednesday, September 26, 2007 5:34 PM

module_method_moved [SomeModule, :method_c] => OtherModule

have intermediary versions that add warnings to methods that are going
away soon (if possible).

Hmmm…

  1. I think, many library authors already put this information to
    changelogs
    in human-readable form (like “Warning! API changed: blah”). I just
    propose
    to do such messages auto-checkable.

  2. I’ve envisioned (but forget to show) the case you saying about:

module MyLibrary::Changelog
version(0.2.5) do
method_deprecated [SomeClass, :method_a], “Will remove this ASAP”
end
end

just one more usage of the idea :slight_smile:

V.