Class: Logicality::Interpreter::SimpleInterpreter

Inherits:
NodeVisitor
  • Object
show all
Defined in:
lib/logicality/interpreter/simple_interpreter.rb

Overview

This class implements NodeVisitor and gives each type of node the proper type of visitor implementation.

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from NodeVisitor

#visit

Constructor Details

#initialize(resolver) ⇒ SimpleInterpreter

Returns a new instance of SimpleInterpreter.

Raises:

  • (ArgumentError) 


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# File 'lib/logicality/interpreter/simple_interpreter.rb', line 17

def initialize(resolver)
  raise ArgumentError, 'Resolver is required' unless resolver

  @resolver = resolver
end

Instance Attribute Details

#resolver ⇒ Object (readonly)

Returns the value of attribute resolver.



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# File 'lib/logicality/interpreter/simple_interpreter.rb', line 15

def resolver
  @resolver
end

Instance Method Details

#error(node) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/logicality/interpreter/simple_interpreter.rb', line 23

def error(node)
  raise ArgumentError, "Visitor cant process node token type: #{node.token.type}"
end

#visit_binary_operator_node(node) ⇒ Object 



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# File 'lib/logicality/interpreter/simple_interpreter.rb', line 27

def visit_binary_operator_node(node)
  if node.token.type == Lexer::Token::Type::AND_OP
    visit(node.left) && visit(node.right)
  elsif node.token.type == Lexer::Token::Type::OR_OP
    visit(node.left) || visit(node.right)
  else
    error(node)
  end
end

#visit_unary_operator_node(node) ⇒ Object 



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# File 'lib/logicality/interpreter/simple_interpreter.rb', line 37

def visit_unary_operator_node(node)
  if node.token.type == Lexer::Token::Type::NOT_OP
    !visit(node.child)
  else
    error(node)
  end
end

#visit_value_operand_node(node) ⇒ Object 



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# File 'lib/logicality/interpreter/simple_interpreter.rb', line 45

def visit_value_operand_node(node)
  if node.value == 'true'
    true
  elsif node.value == 'false' || node.value == 'null'
    false
  else
    resolve_value(node.value)
  end
end