Class: Extract::MathWrapper

Inherits:
Object show all
Includes:
FromHash
Defined in:
lib/extract/math_calc.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#str ⇒ Object

Returns the value of attribute str.



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# File 'lib/extract/math_calc.rb', line 6

def str
  @str
end

Instance Method Details

#apply(l, r) ⇒ Object 



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# File 'lib/extract/math_calc.rb', line 18

def apply(l,r)
  #puts "apply call #{l} #{str} #{r}"
  raise "bad apply, not an operator" unless operator?
  
  #raise "bad apply, L #{l} R #{r}" unless l.to_s.present? && r.to_s.present?  

  l.str = "0" if l.respond_to?(:str) && l.str.blank?
  r.str = "0" if r.respond_to?(:str) && r.str.blank?

  op = str
  op = "**" if op == "^"

  exp = "#{l.to_s} #{op} #{r.to_s}"
  return 0 if exp =~ /infinity/i || exp =~ /[a-z]/i
  #puts "evaling #{exp}"
    #puts "eval, L #{l.class} #{l.inspect} #{str} R #{r.inspect}"
  raise exp if exp =~ /[a-z]/i
  res = eval(exp)
  #puts "evaled #{exp} to #{res}"
  res
end

#left_associative? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/extract/math_calc.rb', line 8

def left_associative?
  true
end

#operator? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/extract/math_calc.rb', line 11

def operator?
  %w(+ - / * ^).include?(str)
end

#precedence ⇒ Object 



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# File 'lib/extract/math_calc.rb', line 14

def precedence
  h = {"*" => 10, "/" => 10, "+" => 5, "-" => 5, "^" => 15}
  h[str]
end

#to_s ⇒ Object 



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# File 'lib/extract/math_calc.rb', line 39

def to_s
  str
end