Class: SRL::Regex::Multiplicity

Inherits:
Object
  • Object
show all
Defined in:
lib/regex/multiplicity.rb

Overview

The multiplicity specifies by how much a given expression can be repeated.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(aLowerBound, anUpperBound, aPolicy) ⇒ Multiplicity

Returns a new instance of Multiplicity.

Parameters:

  • aLowerBound (Integer)
  • anUpperBound (Integer, Symbol) —

    integer or :more symbol

  • aPolicy (Symbol) —

    One of: (:greedy, :lazy, :possessive)



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# File 'lib/regex/multiplicity.rb', line 19

def initialize(aLowerBound, anUpperBound, aPolicy)
  @lower_bound = valid_lower_bound(aLowerBound)
  @upper_bound = valid_upper_bound(anUpperBound)
  @policy = valid_policy(aPolicy)
end

Instance Attribute Details

#lower_bound ⇒ Object (readonly)

The lowest acceptable repetition count



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# File 'lib/regex/multiplicity.rb', line 8

def lower_bound
  @lower_bound
end

#policy ⇒ Object (readonly)

An indicator that specifies how to repeat (:greedy, :lazy, :possessive)



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# File 'lib/regex/multiplicity.rb', line 14

def policy
  @policy
end

#upper_bound ⇒ Object (readonly)

The highest possible repetition count



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# File 'lib/regex/multiplicity.rb', line 11

def upper_bound
  @upper_bound
end

Instance Method Details

#to_str ⇒ Object

Purpose: Return the String representation of the multiplicity.



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# File 'lib/regex/multiplicity.rb', line 26

def to_str()
  case upper_bound
    when :more
      case lower_bound
        when 0
          subresult = '*'
        when 1
          subresult = '+'
        else
          subresult = "{#{lower_bound},}"
      end

    when lower_bound
      subresult = "{#{lower_bound}}"
    else
      if [lower_bound, upper_bound] == [0, 1]
        subresult = '?'
      else
        subresult = "{#{lower_bound},#{upper_bound}}"
      end
  end

  suffix = case policy
    when :greedy
      ''
    when :lazy
      '?'
    when :possessive
      '+'
  end

  return subresult + suffix
end