Class: Basic101::ForStatement

Inherits:
Statement show all
Defined in:
lib/basic101/for_statement.rb

Instance Attribute Summary collapse

Attributes inherited from Statement

#index, #line

Instance Method Summary collapse

Methods inherited from Statement

#data_items, #exec, #line_number, #raise_error_with_line_number

Methods included from Identity

#==

Constructor Details

#initialize(reference, from, to, step) ⇒ ForStatement

Returns a new instance of ForStatement.



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# File 'lib/basic101/for_statement.rb', line 12

def initialize(reference, from, to, step)
  @reference = reference
  @from = from
  @to = to
  @step = step || BasicInteger.new(1)
end

Instance Attribute Details

#reference ⇒ Object (readonly)

attr_writer :next_statement



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# File 'lib/basic101/for_statement.rb', line 10

def reference
  @reference
end

Instance Method Details

#delete_from_stack(runtime) ⇒ Object 



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# File 'lib/basic101/for_statement.rb', line 47

def delete_from_stack(runtime)
  runtime.for_stack.delete_reference(@reference)
end

#done?(runtime) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/basic101/for_statement.rb', line 32

def done?(runtime)
  step = @step.eval(runtime)
  counter = @reference.eval(runtime)
  to = @to.eval(runtime)
  if step.value < 0
    counter.lt(to)
  else
    counter.gt(to)
  end.to_b
end

#execute(runtime) ⇒ Object 



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# File 'lib/basic101/for_statement.rb', line 19

def execute(runtime)
  delete_from_stack(runtime)
  runtime.for_stack.push self
  from = @from.eval(runtime)
  @reference.assign(runtime, from)
end

#goto_following_statement(runtime) ⇒ Object 



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# File 'lib/basic101/for_statement.rb', line 43

def goto_following_statement(runtime)
  runtime.goto_index_after @index
end

#increment(runtime) ⇒ Object 



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# File 'lib/basic101/for_statement.rb', line 26

def increment(runtime)
  step = @step.eval(runtime)
  counter = @reference.eval(runtime)
  @reference.assign(runtime, counter + step)
end