Class: Strategize::Rule

Inherits:
Object
  • Object
show all
Defined in:
lib/strategize/rules/rule.rb

Overview

The Rule class represents a predicate function that can be run against a specific subject.

Define a new rule Rule.new :rule_name, -> { code to execute }

Evaluate a rule rule = Rule.new :rule_name, -> { true } rule.evaluate(nil) #=> true

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, predicate) ⇒ Rule

Create a new rule

Parameters:

  • name (Symbol) —

    a descriptive name for the rule

  • predicate (Proc) —

    code block to be executed



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# File 'lib/strategize/rules/rule.rb', line 18

def initialize(name, predicate)
  unless predicate.respond_to?(:call)
    raise InvalidPredicateError, 'Invalid predicate function passed'
  end

  @name = name
  @predicate = predicate
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/strategize/rules/rule.rb', line 12

def name
  @name
end

#predicate ⇒ Object (readonly)

Returns the value of attribute predicate.



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# File 'lib/strategize/rules/rule.rb', line 12

def predicate
  @predicate
end

Instance Method Details

#evaluate(subject) ⇒ Boolean

Execute the predicate against the subject

Parameters:

  • subject (Object)

Returns:

  • (Boolean) 


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# File 'lib/strategize/rules/rule.rb', line 31

def evaluate(subject)
  subject.instance_exec(&@predicate)
end