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

~~~ruby 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 1337

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 1335

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 1335

def number
  @number
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1354

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 1371

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 1350

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

#disasm(fmt) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1342

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 1359

def length
  3
end

#pops ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1363

def pops
  1
end

#pushes ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1367

def pushes
  number
end

#to_a(_iseq) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1346

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