From: Max Schmidt <max.schmidt.privat@...>
Date: 2010-03-31T23:58:03+09:00
Subject: Re: RubyDictionary - First Try

>> 3 -
>>>Why don't you allow one letter words?
>> Because strings with one letter aren't any words, they are characters.
>> My aim was to develop a dictionary where you can organize "real-life"
>> words
> 
> "a" is a word :-)
This is a good argument, I was obviously too focused on my native 
language :)

>>>if (match!=nil && match[0].length == word.length) then true
>>
>>>def self.is_word? word
>>> �word.match(/\A[:alpha:][:alpha:]+\z/) #you can remove the first
>>>[:alpha:] to allow 1-letter words
>>>end
>>
>> I wanted to limit the word's length to 15 as you can see in my regular
>> expression. Are the "\A" (start position) and "\z" (end position)
>> necessary?
> 
> It's a way of saying that the full string should match your
> restrictions. It avoids having to check that the match is equal to the
> length of the original string:
> 
> def self.is_word? word
>   word.match(/\A[:alpha]{2,15}\z/)
> end
> 
> should do what you want.
Oh, now I understand. Checking the length of the original string was a 
work-a-round, because I did not know about this regexp feature :)


>> Do you mean to avoid exceptions when the words are frozen? If yes, I
>> would throw an Exception if either of the two words is frozen.
> 
> No, what I mean is that the client can modify the String object after
> inserting it in the dictionary:
You surely mean the DictionaryEntry

> @word1 = word1.dup unless word1.frozen?
> @word2 = word2.dup unless word2.frozen?
> 
> The frozen check is just an optimization, because if the string is
> frozen it's not going to be modified by the client, and so you are
> safe just using it.
> 
If you assume that word1 is frozen, then @word1 would be assigned to 
nil, wouldn't it? Or is the unless refering to the - and exclusively - 
to the ".dup"?

> If it's just for
> convenience, I think you should drop it, because it's giving those
> objects a behaviour that they shouldn't have.

Do you mean that the boolean equality operator (==) normally exclusively 
compares with the class it is defined by?

> Another idea: if want to see the dictionary as a set of things, a
> common thing is to include Enumerable and provide an each method, so
> that the clients of the dictionary can use the cool methods Enumerable
> provides.
Nice idea, I implemented this.

Last question:
I posted this code on an other ruby forum and was criticized about my 
coding style: Indents are always done with two whitespaces rather than 
with tabs like I have. Have you heard anything about such a "unwritten 
rule"?

Thanks
-- 
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