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 1447

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 1445

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 1445

def number
  @number
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1464

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 1485

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 1481

def canonical
  self
end

#deconstruct_keys(_keys) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1460

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

#disasm(fmt) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1452

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 1469

def length
  3
end

#pops ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1473

def pops
  1
end

#pushes ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1477

def pushes
  number
end

#to_a(_iseq) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1456

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