Class: So::Exists

Inherits:
Expr show all
Defined in:
lib/spec_object.rb

Instance Method Summary collapse

Methods inherited from Expr

#!, #<, #==, #>, #[], #assert_time, #assert_value, #to_so_expr

Constructor Details

#initialize(variable, expr) ⇒ Exists

Returns a new instance of Exists.



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# File 'lib/spec_object.rb', line 286

def initialize(variable, expr)
  raise "expected variable" unless variable.is_a?(Variable)

  @variable = variable
  @expr = expr.to_so_expr
end

Instance Method Details

#evaluate(calls) ⇒ Object 



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# File 'lib/spec_object.rb', line 302

def evaluate(calls)
  if @variable.time?
    posibilities =
      (0...calls.size).map do |t|
        v = @expr.substitute(@variable, Time.new(t)).evaluate(calls)
      end

    t =
      posibilities.any? do |v|
        v.kind_of?(Const) && v.value
      end

    if t
      true.to_so_expr
    else
      f =
        posibilities.all? do |v|
          v.kind_of?(Const) && !(v.value)
        end

      if f
        false.to_so_expr
      else
        self
      end
    end
  elsif @variable.value?
    self
  else
    raise "cannot infer the type of #{@variable.pp(0)}"
  end
end

#pp(n) ⇒ Object 



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# File 'lib/spec_object.rb', line 293

def pp(n)
  "#{' '*n}(exists #{@variable.pp(0)}\n#{@expr.pp(n+2)})"
end

#substitute(v, e) ⇒ Object 



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# File 'lib/spec_object.rb', line 297

def substitute(v, e)
  raise "bad thing happ(n)ened" if v.object_id == @variable.object_id
  Exists.new(@variable, @expr.substitute(v, e))
end