Class: Flea::Interpreter

Inherits:
Object
  • Object
show all
Defined in:
lib/flea/interpreter.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(environment: Environment.new, standard_library: true) ⇒ Interpreter

Returns a new instance of Interpreter.



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# File 'lib/flea/interpreter.rb', line 7

def initialize(environment: Environment.new, standard_library: true)
  @base_environment = @current_environment = environment

  load_standard_library if standard_library
end

Instance Attribute Details

#base_environment ⇒ Object

Returns the value of attribute base_environment.



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# File 'lib/flea/interpreter.rb', line 5

def base_environment
  @base_environment
end

#current_environment ⇒ Object

Returns the value of attribute current_environment.



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# File 'lib/flea/interpreter.rb', line 5

def current_environment
  @current_environment
end

Instance Method Details

#evaluate(expression) ⇒ Object 



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# File 'lib/flea/interpreter.rb', line 31

def evaluate(expression)
  return @current_environment.find(expression) if expression.is_a? Symbol
  return expression unless expression.is_a? Array

  case expression[0]
  when :define then @current_environment.define(expression[1], evaluate(expression[2]))
  when :native_function then eval expression[1]
  else
    function = evaluate(expression[0])
    raise "\n#{to_sexp(expression)}\n ^\n\n#{expression[0]} is not a function\n\n#{@current_environment.table.keys}" unless function.is_a? Proc

    arguments = expression.slice(1, expression.length)
    function.call(arguments, self)
  end
end

#parse(string) ⇒ Object 



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# File 'lib/flea/interpreter.rb', line 47

def parse(string)
  Sexpistol.parse(string, parse_ruby_keyword_literals: true)
end

#run(program) ⇒ Object 



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# File 'lib/flea/interpreter.rb', line 13

def run(program)
  program = parse(program)
  result = nil
  


  if program.is_a?(Sexpistol::SExpressionArray)
    program.each do |expression|
      result = evaluate(expression)
    end
    
  else
    result = evaluate(program)
  end

  result
end

#to_sexp(expression) ⇒ Object 



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# File 'lib/flea/interpreter.rb', line 51

def to_sexp(expression)
  Sexpistol.to_sexp(expression, scheme_compatability: true)
end