Class: MakesSense::DecisionTable

Inherits:
Object
  • Object
show all
Defined in:
lib/makes_sense/decision_table.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, conditions, result_table, args) ⇒ DecisionTable

Returns a new instance of DecisionTable.



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# File 'lib/makes_sense/decision_table.rb', line 10

def initialize(name, conditions, result_table, args)
  @name = name
  @conditions = conditions
  @result_table = result_table
  @args = args
end

Class Method Details

.define(name, &block) ⇒ Object 



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# File 'lib/makes_sense/decision_table.rb', line 17

def self.define(name, &block)
  dsl = DecisionTableDsl.new
  dsl.instance_eval(&block)
  new(name, dsl.conditions, dsl.result_table, dsl.args)
end

Instance Method Details

#validate ⇒ Object 



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# File 'lib/makes_sense/decision_table.rb', line 23

def validate
  condition_values = @conditions.map(&:values)
  possible_conditions = condition_values[0].product(*condition_values[1..])
  expanded_rows = expand_rows
  expanded_row_conditions = expanded_rows.map(&:conditions)

  errors = []

  possible_conditions.each do |possible_condition|
    unless expanded_row_conditions.include?(possible_condition)
      errors << {
        type: :missing,
        message: "Missing result condition: #{possible_condition}",
        expected_conditions: possible_condition,
        expected: {}.tap do |condition_map|
          @conditions.each_with_index do |condition, index|
            condition_map[condition.name] = possible_condition[index]
          end
        end
      }
    end
  end

  visited = []

  expanded_rows.each do |row|
    found_index = visited.find_index(row.conditions)
    if found_index
      errors << {
        type: :duplicate,
        message: "Duplicate result #{row.conditions} for rows #{found_index} and #{row.row_index}",
        row: row,
        duplicate_index: found_index
      }
    end

    visited << row.conditions
  end

  if !errors.empty?
    Failure.new(errors)
  else
    Success.new(self)
  end
end

#with_ruleset(ruleset) ⇒ Object 



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# File 'lib/makes_sense/decision_table.rb', line 69

def with_ruleset(ruleset)
  ->(**kwargs) do
    expanded_rows = expand_rows

    ruleset_results = @conditions.map do |condition|
      method_kwarg_names = ruleset.method(condition.name).parameters.map { |parameter| parameter[1] }
      args = method_kwarg_names.map { |kwarg_name| kwargs[kwarg_name] }
      ruleset.public_send(condition.name, *args)
    end

    result_row = @result_table.rows.find do |row|
      row.conditions == ruleset_results
    end

    if result_row.results.respond_to?(:call)
      method_kwarg_names = result_row.results.parameters.map { |parameter| parameter[1] }
      args = method_kwarg_names.map { |kwarg_name| kwargs[kwarg_name] }
      result_row.results.call(*args)
    else
      result_row.results
    end
  end
end