From: "Victor \"Zverok\" Shepelev" <vshepelev@...>
Date: 2006-12-06T10:07:01+09:00
Subject: Re: Lisp comprehensions => SQL

From: khaines@enigo.com [mailto:khaines@enigo.com]
Sent: Wednesday, December 06, 2006 2:46 AM
>On Wed, 6 Dec 2006, Victor "Zverok" Shepelev wrote:
>
>A lot of these things are either supported in Kansas, or are in the
>drawing board for when I can get back to Kansas development.
>
>> 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]
>
>Current Kansas:
>
>dbh.select(:Employees) do |e|
>   sort_by(e.age)
>   limit(2,10)
>   (e.name == 'John') & (e.salary > 50)
>end
>
>Future Kansas:
>
>employees = Kansas::DBNAME::Employees
>employees.select do |e|
>   sort_by(e.age)
>   limit(2,10)
>   (e.name == 'John') & (e.salary > 50)
>end
>
>> employees.select{|e| e.salary < 150}.count
>
>Current:
>
>dbh.count(:Employees) {|e| e.salary < 150}
>
>Future:
>
>employees.count {|e| e.salary < 150}
>
>> employees = Table.new(:id, :name, :sec_name, :salary, :age)
>> positions = Table.new(:id, :employee_id, :position_name)
>>
>> (employees + positions).select{|e, p| e.id == p.employee_id}
>
>Current:
>
>dbh.select(:Employees, :Positions) {|e,p| e.id == p.employee_id}
>
>
>I have not worked on Kansas much in the last year because it is stable for
>me, but there are a number of things that I have planned when I can set
>aside some time to get back around to it.
>

Interesting. But I still don't understand, why to use custom DSL instead of
familiar Ruby (ok, with changin && => &)

#having
employees.select do |e|
   sort_by(e.age)
   limit(2,10)
   (e.name == 'John') & (e.salary > 50)
end

#proposal:

employees.select{|e| (e.name == 'John') & (e.salary > 50)}.sort_by{|e|
e.age}[2..10]

The latter is "just Ruby".

V.