Class: CodeExecuteThenPopInstruction

Inherits:
Instruction show all
Defined in:
lib/instructions/code/code_execute_then_pop.rb

Overview

peeks at the top item from the :code stack (without popping it!); pushes a new block containing that code value and “do code_pop” onto the :exec stack, so the item is executed, then removed from the :code stack

needs: 1 :code

pushes: 1 :exec

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/code/code_execute_then_pop.rb', line 26

def cleanup
  pushes :exec, @result
end

#derive ⇒ Object 



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# File 'lib/instructions/code/code_execute_then_pop.rb', line 18

def derive
  that_becomes = NudgeProgram.new(@arg)
  if that_becomes.parses?
    @result = CodeblockPoint.new([NudgeProgram.new(@arg).linked_code,InstructionPoint.new("code_pop")])
  else
    @result = CodeblockPoint.new([InstructionPoint.new("code_pop")])
  end
end

#preconditions? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/instructions/code/code_execute_then_pop.rb', line 11

def preconditions?
  needs CodePopInstruction
  needs :code, 1
end

#setup ⇒ Object 



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# File 'lib/instructions/code/code_execute_then_pop.rb', line 15

def setup
  @arg = @context.peek_value(:code) # does not pop the stack initially!
end