Class: Cadenza::OperationNode

Inherits:
Object
  • Object
show all
Defined in:
lib/cadenza/nodes/operation_node.rb

Overview

The OperationNode is a node which contains an evaluatable #left and #right subtree and an #operator with which to evaluate it.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(left, operator, right) ⇒ OperationNode

creates a new Cadenza::OperationNode with the given left and right subtrees and the given operator.



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# File 'lib/cadenza/nodes/operation_node.rb', line 35

def initialize(left, operator, right)
   @left = left
   @right = right
   @operator = operator
end

Instance Attribute Details

#leftVariableNode|ConstantNode|OperationNode|BooleanInverseNode

Returns the root of the left subtree to evaluate for this operation.

Returns:



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# File 'lib/cadenza/nodes/operation_node.rb', line 7

def left
  @left
end

#operatorString

The operation of this node to do when evaluating. The operator should be one of the following values:

  • “==” for equal

  • “!=” for not equal

  • “>=” for greater than or equal to

  • “<=” for less than or equal to

  • “>” for greater than

  • “<” for less than

  • “and” for the boolean 'and' conjunction

  • “or” for the boolean 'or' conjunction

  • “+” for the arithmetic addition operation

  • “-” for the arithmetic subtraction operation

  • “*” for the arithmetic multiplication operation

  • “/” for the arithmetic division operation

Returns:

  • (String)

    the operation for this node



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# File 'lib/cadenza/nodes/operation_node.rb', line 28

def operator
  @operator
end

#rightVariableNode|ConstantNode|OperationNode|BooleanInverseNode

Returns the root of the right subtree to evaluate for this operation.

Returns:



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# File 'lib/cadenza/nodes/operation_node.rb', line 11

def right
  @right
end

Instance Method Details

#==(rhs) ⇒ Boolean

Returns true if the given Cadenza::OperationNode is equivalent by value to this node.

Parameters:

Returns:



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# File 'lib/cadenza/nodes/operation_node.rb', line 100

def ==(rhs)
   @operator == rhs.operator and
   @left == rhs.left and
   @right == rhs.right
end

#eval(context) ⇒ Object

Evalutes the left and right subtree in the given context and uses the #operator to manipulate the two values into a single output value which is then returned.

Parameters:

Returns:

  • (Object)

    the result of performing the operation on the evaluated left and right subtrees in the given context.



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# File 'lib/cadenza/nodes/operation_node.rb', line 52

def eval(context)
   l = @left.eval(context)
   r = @right.eval(context)

   case @operator
      when '=='
         return l == r

      when '!='
         return l != r

      when '>='
         return l >= r

      when '<='
         return l <= r

      when '>'
         return l > r

      when '<'
         return l < r

      when 'and'
         return l && r

      when 'or'
         return l || r

      when '+'
         return l + r

      when '-'
         return l - r

      when '*'
         return l * r

      when '/'
         return l / r

      else throw "undefined operator: #{@operator}"
   end
end

#implied_globalsArray

Returns a list of variable names implied to be global in this node

Returns:

  • (Array)

    a list of variable names implied to be global in this node



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# File 'lib/cadenza/nodes/operation_node.rb', line 42

def implied_globals
   @left.implied_globals | @right.implied_globals
end