From: ts <decoux@...>
Date: 2005-01-14T00:07:50+09:00
Subject: Re: Duck Typing as Pattern Matching

>>>>> "i" == itsme213  <itsme213@hotmail.com> writes:

i> My claim is this: If you redefine #method_missing so your object handles
i> x.foo as the caller would expect, then you _should_ define
i> x.respond_to?(:foo) to return true. I do not claim that Ruby should prohibit
i> code that does not do this.

 well, difficult, for me, to reply because you must see the underlying C++
 interface (DbXml) to see why bdbxml do this.

 Normally the code must be written

  p txn.manager.create_modify

 i.e.

   `txn.create_modify' is *exactly* the same than `txn.manager.create_modify'

 but, to give you, another example

uln% cat b.rb
#!/usr/local/bin/ruby
$LOAD_PATH.unshift("../src")
require 'bdbxml'

txn = BDB::Env.new("tmp",BDB::CREATE|BDB::INIT_TRANSACTION).manager.
   transaction
p txn.respond_to?(:create_container)
p txn.create_container("aaa")
txn.commit
uln% 

uln% b.rb
true
#<BDB::XML::Container:0x2a955b2ef8>
uln% 

 in this case `txn.create_container' is *really* different from
 `txn.manager.create_container'

 Transaction#create_modify is just a convenient method.


Guy Decoux