Class: Predicated::Predicate::SexpToPredicate

Inherits:
Object
  • Object
show all
Defined in:
lib/predicated/from/ruby_code_string.rb

Constant Summary collapse

SIGN_TO_PREDICATE_CLASS = 
{
  :== => Equal,
  :> => GreaterThan,
  :< => LessThan,
  :>= => GreaterThanOrEqualTo,
  :<= => LessThanOrEqualTo,
}

Instance Method Summary collapse

Constructor Details

#initialize(context) ⇒ SexpToPredicate

Returns a new instance of SexpToPredicate.



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# File 'lib/predicated/from/ruby_code_string.rb', line 24

def initialize(context)
  @context = context
end

Instance Method Details

#convert(sexp) ⇒ Object 



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# File 'lib/predicated/from/ruby_code_string.rb', line 28

def convert(sexp)
  first_element = sexp.first
  if first_element == :block
    #eval all the top lines and then treat the last one as a predicate
    body_sexps = sexp.sexp_body.to_a
    body_sexps.slice(0..-2).each do |upper_sexp|
      eval_sexp(upper_sexp)
    end
    convert(body_sexps.last)
  elsif first_element == :call
    sym, left_sexp, method_sym, right_sexp = sexp
    left = eval_sexp(left_sexp)
    right = eval_sexp(right_sexp)

    if operation_class=SIGN_TO_PREDICATE_CLASS[method_sym]
      operation_class.new(left, right)
    else
      Call.new(left, method_sym, right)
    end
  elsif first_element == :and
    sym, left, right = sexp
    And.new(convert(left), convert(right))
  elsif first_element == :or
    sym, left, right = sexp
    Or.new(convert(left), convert(right))
  elsif first_element == :not
    sym, inner = sexp
    Not.new(convert(inner))
  else
    raise DontKnowWhatToDoWithThisSexpError.new(sexp)
  end
end

#eval_sexp(sexp) ⇒ Object 



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# File 'lib/predicated/from/ruby_code_string.rb', line 61

def eval_sexp(sexp)
  eval(Ruby2Ruby.new.process(sexp), @context)
end