I have an array that looks like this:
conditions = []
conditions << Proc.new { where(own_property: 1) }
conditions << Proc.new { where(case_enabled: true) }
conditions
=> [#<Proc:0x007fb4675acc10@(irb):4>, #<Proc:0x007fb4675a5640@(irb):5>]
I have ActiveRecord query methods encapsulated in proc objects stored in an array. I am trying to find a way to take this array and then invoke it like so:
Practice.where(own_property: 1).where(case_enabled: true)
Someone showed me the technique of passing a proc to an object so that it gets evaluated in the context of that object:
Practice.instance_eval(&p)
Above we use the unary &
to convert a single proc object into a block, which then gets evaluated in the context of Practice. This works great. But what about an array of Procs? Trying to use &
on an array of procs obviously does not work:
Practice.instance_eval(&conditions)
TypeError: wrong argument type Array (expected Proc)
If I try to call the proc objects before passing them as a block to Practice.instance_eval
, they get evaluated in context of their original definition:
Practice.instance_eval(&conditions.map(&:call))
NoMethodError: undefined method `where' for main:Object
Is there another way to get these array of procs evaluated in context of Practice?
看来我已经使用方便的reduce(aka inject)方法工作了:
conditions.inject(Practice) {|model, p| model.instance_eval(&p)}
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