Class: DigitsSolver::Solution

Inherits:
Object
  • Object
show all
Includes:
DigitsSolver::Strategies::Base
Defined in:
lib/digits_solver/solution.rb

Overview

This is the class that represents a solution to the problem.

Constant Summary

Constants included from DigitsSolver::Strategies::Base

DigitsSolver::Strategies::Base::OPERATIONS

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from DigitsSolver::Strategies::Base

#solve

Constructor Details

#initialize(problem_statement, operands, operations_to_apply) ⇒ Solution

Returns a new instance of Solution.

Raises:



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# File 'lib/digits_solver/solution.rb', line 11

def initialize(problem_statement, operands, operations_to_apply)
  raise DigitsSolver::Error, 'Invalid problem statement' unless problem_statement.is_a? DigitsSolver::ProblemStatement
  unless operands.size == operations_to_apply.size + 1
    raise DigitsSolver::Error, "Invalid solution #{operands.inspect} => #{operations_to_apply.inspect}"
  end

  @problem_statement = problem_statement
  @operands = operands
  @operations_to_apply = operations_to_apply
end

Instance Attribute Details

#operands ⇒ Object (readonly)

Returns the value of attribute operands.



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# File 'lib/digits_solver/solution.rb', line 9

def operands
  @operands
end

#operations_to_apply ⇒ Object (readonly)

Returns the value of attribute operations_to_apply.



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# File 'lib/digits_solver/solution.rb', line 9

def operations_to_apply
  @operations_to_apply
end

#problem_statement ⇒ Object (readonly)

Returns the value of attribute problem_statement.



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# File 'lib/digits_solver/solution.rb', line 9

def problem_statement
  @problem_statement
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/digits_solver/solution.rb', line 22

def ==(other)
  (operations_to_apply == other.operations_to_apply) && (operands == other.operands)
end

#pretty_print(pp) ⇒ Object 



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# File 'lib/digits_solver/solution.rb', line 46

def pretty_print(pp)
  pp.object_address_group(self) do
    pp.breakable
    pp.text "Solution: '#{to_evaluable_code} = #{problem_statement.target_number}'"
    pp.text ','
    pp.breakable
    pp.seplist(instance_variables) do |v|
      pp.text "#{v}="
      pp.pp instance_variable_get v
    end
  end
end

#to_evaluable_code ⇒ Object 



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# File 'lib/digits_solver/solution.rb', line 59

def to_evaluable_code
  # parenthesis management is ... meh, but better than nothing, and at least mathematically correct.
  evaluable_code = operations_to_apply.each.with_index.reduce(operands.first) do |res, (operation, idx)|
    op1 = res
    op2 = operands[idx + 1]
    format_string = operation == :multiply ? '%s %s %u' : '(%s %s %u)'
    format(format_string, op1, DigitsSolver::Strategies::Base::OPERATIONS[operation], op2)
  end
  evaluable_code[-1] == ')' ? evaluable_code[1...-1] : evaluable_code
end

#to_operation_lines ⇒ Object 



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# File 'lib/digits_solver/solution.rb', line 32

def to_operation_lines
  res = []
  operations_to_apply.each.with_index.reduce(operands.first) do |acc, (operation, idx)|
    computed_result = apply_operation_to_operands operation, acc, operands[idx + 1]
    res << format(' => %u %s %u = %u',
                  acc,
                  DigitsSolver::Strategies::Base::OPERATIONS[operation],
                  operands[idx + 1],
                  computed_result)
    computed_result
  end
  res
end

#to_s ⇒ Object 



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# File 'lib/digits_solver/solution.rb', line 26

def to_s
  res = ["Solved in #{operations_to_apply.size} operation#{operations_to_apply.size <= 1 ? "" : "s"}:"]
  res.concat to_operation_lines
  res.join "\n"
end