Class: SyntaxTree::YARV::ExpandArray

Inherits:
Instruction 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

x, = [true, false, nil]

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Instruction

#branch_targets, #canonical, #falls_through?, #leaves?, #side_effects?

Constructor Details

#initialize(number, flags) ⇒ ExpandArray

Returns a new instance of ExpandArray.



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1448

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 1446

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 1446

def number
  @number
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1465

def ==(other)
  other.is_a?(ExpandArray) && other.number == number &&
    other.flags == flags
end

#call(vm) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1482

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

#deconstruct_keys(_keys) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1461

def deconstruct_keys(_keys)
  { number: number, flags: flags }
end

#disasm(fmt) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1453

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 1470

def length
  3
end

#pops ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1474

def pops
  1
end

#pushes ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1478

def pushes
  number
end

#to_a(_iseq) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1457

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