Class: SyntaxTree::YARV::ExpandArray

Inherits:
Object
  • Object
show all
Defined in:
lib/syntax_tree/yarv/instructions.rb

Overview

### Summary

expandarray looks at the top of the stack, and if the value is an array it replaces it on the stack with number elements of the array, or nil if the elements are missing.

### Usage

~~~ruby x, = [true, false, nil] ~~~

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(number, flags) ⇒ ExpandArray 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1297

def initialize(number, flags)
  @number = number
  @flags = flags
end

Instance Attribute Details

#flags ⇒ Object (readonly)

Returns the value of attribute flags.



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1295

def flags
  @flags
end

#number ⇒ Object (readonly)

Returns the value of attribute number.



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1295

def number
  @number
end

Instance Method Details

#call(vm) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1326

def call(vm)
  object = vm.pop
  object =
    if Array === object
      object.dup
    elsif object.respond_to?(:to_ary, true)
      object.to_ary
    else
      [object]
    end

  splat_flag = flags & 0x01 > 0
  postarg_flag = flags & 0x02 > 0

  if number == 0 && splat_flag == 0
    # no space left on stack
  elsif postarg_flag
    values = []

    if number > object.size
      (number - object.size).times { values.push(nil) }
    end
    [number, object.size].min.times { values.push(object.pop) }
    values.push(object.to_a) if splat_flag

    values.each { |item| vm.push(item) }
  else
    values = []

    [number, object.size].min.times { values.push(object.shift) }
    if number > values.size
      (number - values.size).times { values.push(nil) }
    end
    values.push(object.to_a) if splat_flag

    values.reverse_each { |item| vm.push(item) }
  end
end

#canonical ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1322

def canonical
  self
end

#disasm(fmt) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1302

def disasm(fmt)
  fmt.instruction("expandarray", [fmt.object(number), fmt.object(flags)])
end

#length ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1310

def length
  3
end

#pops ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1314

def pops
  1
end

#pushes ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1318

def pushes
  number
end

#to_a(_iseq) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1306

def to_a(_iseq)
  [:expandarray, number, flags]
end