Operast README¶ ↑

Release: $Release$

operast.rubyforge.org/

About¶ ↑

Operast (Operator + AST) is a library to convert Ruby expression into other language. Currently, only SQL is supported.

Operast requires Ruby 1.8 or later.

Example¶ ↑

require 'operast'
require 'operast/translator/sql'

x = Operast::Variable.new('x')
y = Operast::Variable.new('y')
t = Operast::SqlTranslator.new

p t.translate(x)                     #=> "x"
p t.translate(x + 1)                 #=> "(x + 1)"
p t.translate(x + y)                 #=> "(x + y)"
p t.translate(x * y + 2)             #=> "((x * y) + 2)"
p t.translate(x + y * 2)             #=> "(x + (y * 2))"
p t.translate(x ** y)                #=> "power(x,y)"
p t.translate(x > 0)                 #=> "(x > 0)"
p t.translate(y < 1)                 #=> "(y < 1)"
p t.translate(x == 0)                #=> "(x = 0)"
p t.translate(y ^ "who's who")       #=> "(y <> 'who\\'s who')"
p t.translate(y <=> 3.14)            #=> "(y <> 3.14)"
p t.translate((x > 0) & (y < 1))     #=> "((x > 0) and (y < 1))"
p t.translate((x == 0) | (y ^ 1))    #=> "((x = 0) or (y <> 1))"
p t.translate(x == nil)              #=> "(x is null)"
p t.translate(x <=> nil)             #=> "(x is not null)"
p t.translate(x =~ '%pattern%')      #=> "(x like '%pattern%')"
p t.translate(x.in?([10,20,30]))     #=> "(x in (10,20,30))"
p t.translate(x.in?(10..30))         #=> "(x between 10 and 30)"

Restrictions¶ ↑

‘x + 1’ is OK, but ‘1 + x’ is NG.
‘x & y’ is OK, but ‘x && y’ is NG.
‘x != y’ is NG in Ruby 1.8. Use ‘x ^ y’ or ‘x <=> y’ instead.
function (such as sum() or avg()) is not supported.

License¶ ↑

$License$

Author¶ ↑

makoto kuwata <kwa.at.kuwata-lab.com>