Class: IntSubtractInstruction

Inherits:
Instruction show all
Defined in:
lib/instructions/int/int_subtract.rb

Overview

pops the top 2 items of the :int stack; pushes a ValuePoint with their difference onto the :int stack

note: the top item is the value subtracted from the second stack item’s value

needs: 2 :int

pushes: 1 :int

Instance Attribute Summary

Attributes inherited from Instruction

#context

Instance Method Summary collapse

Methods inherited from Instruction

all_instructions, #go, inherited, #initialize, #needs, #pushes, to_nudgecode

Constructor Details

This class inherits a constructor from Instruction

Instance Method Details

#cleanup ⇒ Object 



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# File 'lib/instructions/int/int_subtract.rb', line 23

def cleanup
  pushes :int, @result
end

#derive ⇒ Object 



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# File 'lib/instructions/int/int_subtract.rb', line 19

def derive
    @diff = @arg1-@arg2
    @result = ValuePoint.new("int", @diff)
end

#preconditions? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/instructions/int/int_subtract.rb', line 12

def preconditions?
  needs :int, 2
end

#setup ⇒ Object 



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# File 'lib/instructions/int/int_subtract.rb', line 15

def setup
  @arg2 = @context.pop_value(:int)
  @arg1 = @context.pop_value(:int)
end