From: "Victor \"Zverok\" Shepelev" <vshepelev@...>
Date: 2006-12-06T07:27:31+09:00
Subject: Re: Lisp comprehensions => SQL

From: Logan Capaldo [mailto:logancapaldo@gmail.com]
Sent: Wednesday, December 06, 2006 12:15 AM
>To: ruby-talk ML
>Subject: Re: Lisp comprehensions => SQL
>
>On Wed, Dec 06, 2006 at 06:58:49AM +0900, Victor Zverok Shepelev wrote:
>> Hi all.
>>
>> Random idea, just for fun - using "list comprehensions" for SQL queries
>> generation.
>>
>> employees = Table.new(:id, :name, :sec_name, :salary, :age)
>>
>> employees.select{|e| e.name == 'John' && e.salary > 50}.sort_by{|e|
>> e.age}[2,10]
>>
>> #generates "select * from Employees where name = 'John' and salary > 50
>> order by age limit 2,10"
>>
>> employees.select{|e| e.salary < 150}.count
>>
>> #generates "select count(*) from Employees where salary < 150
[...]
>The ez_where plugin for rails does this.
>http://brainspl.at/articles/2006/01/30/i-have-been-busy

Yeah, seems to be close to my proposition.
What I dislike in the solution (and in Mongoose, which repeats the solution)
that conditions is NOT plain Ruby, but custom DSL.

#ez_where:

articles = Article.ez_find(:all, :include => :author) do |article, author|
  article.title =~ "%Foo Title%"
  author.any do
    name == 'Ezra'
    name == 'Fab'
  end 
end

#my idea, thus lacking knowledge about tables relationships:

(articles+authors).select{|article, author| 
   article.author_id == author.id && 
   article.title =~ "%Foo Title%" && 
   (author.name == 'Ezra' || author.name == 'Fab')
}

Seems to read as "just ruby". 
What do you think about?

BTW, I think about some common "over-DSL-ing" between DSL-addict.
It's something like "Syntactic saccharin"[1] - seems to be "very cool", but
no added value.

V.

1. http://en.wikipedia.org/wiki/Syntactic_sugar#Syntactic_saccharin