Class: Rubinius::ToolSet.current::TS::AST::MultipleAssignment

Inherits:
Node
  • Object
show all
Defined in:
lib/rubinius/ast/variables.rb

Instance Attribute Summary collapse

Attributes inherited from Node

#line

Instance Method Summary collapse

Methods inherited from Node

#ascii_graph, #attributes, #children, match_arguments?, match_send?, #new_block_generator, #new_generator, #node_name, #or_bytecode, #pos, #set_child, transform, #transform, transform_comment, transform_kind, transform_kind=, transform_name, #value_defined, #visit, #walk

Constructor Details

#initialize(line, left, right, splat) ⇒ MultipleAssignment

Returns a new instance of MultipleAssignment.



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# File 'lib/rubinius/ast/variables.rb', line 546

def initialize(line, left, right, splat)
  @line = line
  @left = left
  @right = right
  @splat = nil
  @block = nil # support for |&b|
  @post = nil # in `a,*b,c`, c is in post.

  if splat.kind_of?(PostArg)
    @fixed = false
    @post = splat.rest
    splat = splat.into
  elsif right.kind_of?(ArrayLiteral)
    @fixed = right.body.size > 1
  else
    @fixed = false
  end

  if splat.kind_of? Node
    if @left
      if right
        @splat = SplatAssignment.new line, splat
      else
        @splat = SplatWrapped.new line, splat
      end
    elsif @fixed
      @splat = SplatArray.new line, splat, right.body.size
    elsif right.kind_of? SplatValue
      @splat = splat
    else
      @splat = SplatWrapped.new line, splat
    end
  elsif splat
    # We need a node for eg { |*| } and { |a, *| }
    size = @fixed ? right.body.size : 0
    @splat = EmptySplat.new line, size
  end
end

Instance Attribute Details

#block ⇒ Object

Returns the value of attribute block.



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# File 'lib/rubinius/ast/variables.rb', line 544

def block
  @block
end

#left ⇒ Object

Returns the value of attribute left.



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# File 'lib/rubinius/ast/variables.rb', line 544

def left
  @left
end

#post ⇒ Object

Returns the value of attribute post.



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# File 'lib/rubinius/ast/variables.rb', line 544

def post
  @post
end

#right ⇒ Object

Returns the value of attribute right.



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# File 'lib/rubinius/ast/variables.rb', line 544

def right
  @right
end

#splat ⇒ Object

Returns the value of attribute splat.



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# File 'lib/rubinius/ast/variables.rb', line 544

def splat
  @splat
end

Instance Method Details

#bytecode(g, array_on_stack = false) ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 650

def bytecode(g, array_on_stack=false)
  unless array_on_stack
    g.cast_array unless @right or (@splat and not @left)
  end

  declare_local_scope(g.state.scope)

  if @fixed
    pad_short(g) if @left and !@splat
    @right.body.each { |x| x.bytecode(g) }

    if @left
      make_retval(g)

      if @splat
        pad_short(g)
        make_array(g)
      end

      rotate(g)

      g.state.push_masgn
      @left.body.each do |x|
        x.bytecode(g)
        g.pop
      end
      g.state.pop_masgn

      pop_excess(g) unless @splat
    end
  else
    if @right
      if @right.kind_of? ArrayLiteral and @right.body.size == 1
        @right.body.first.bytecode(g)
        g.cast_multi_value
      else
        @right.bytecode(g)
      end

      g.cast_array unless @right.kind_of? ToArray
      g.dup # Use the array as the return value
    end

    if @left
      g.state.push_masgn
      @left.body.each do |x|
        g.shift_array
        g.cast_array if x.kind_of? MultipleAssignment and x.left
        x.bytecode(g)
        g.pop
      end
      g.state.pop_masgn
    end

    if @post
      g.state.push_masgn
      @post.body.each do |x|
        g.dup
        g.send :pop, 0
        g.cast_array if x.kind_of? MultipleAssignment and x.left
        x.bytecode(g)
        g.pop
      end
      g.state.pop_masgn
    end
  end

  if @splat
    g.state.push_masgn
    @splat.bytecode(g)

    # Use the array as the return value
    g.dup if @fixed and !@left

    g.state.pop_masgn
  end

  g.pop if @right and (!@fixed or @splat)
end

#declare_local_scope(scope) ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 627

def declare_local_scope(scope)
  # Fix the scope for locals introduced by the left. We
  # do this before running the code for the right so that
  # right side sees the proper scoping of the locals on the left.

  if @left
    @left.body.each do |var|
      case var
      when LocalVariable
        scope.assign_local_reference var
      when MultipleAssignment
        var.declare_local_scope(scope)
      end
    end
  end

  if @splat and @splat.kind_of?(SplatAssignment)
    if @splat.value.kind_of?(LocalVariable)
      scope.assign_local_reference @splat.value
    end
  end
end

#defined(g) ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 730

def defined(g)
  g.push_literal "assignment"
end

#iter_arguments ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 623

def iter_arguments
  @iter_arguments = true
end

#make_array(g) ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 598

def make_array(g)
  size = @right.body.size - @left.body.size
  g.make_array size if size >= 0
end

#make_retval(g) ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 603

def make_retval(g)
  size = @right.body.size
  if @left and !@splat
    lhs = @left.body.size
    size = lhs if lhs > size
  end
  g.dup_many @right.body.size
  g.make_array @right.body.size
  g.move_down size
end

#pad_short(g) ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 585

def pad_short(g)
  short = @left.body.size - @right.body.size
  if short > 0
    short.times { g.push :nil }
    g.make_array 0 if @splat
  end
end

#pop_excess(g) ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 593

def pop_excess(g)
  excess = @right.body.size - @left.body.size
  excess.times { g.pop } if excess > 0
end

#rotate(g) ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 614

def rotate(g)
  if @splat
    size = @left.body.size + 1
  else
    size = @right.body.size
  end
  g.rotate size
end

#to_sexp ⇒ Object 



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# File 'lib/rubinius/ast/variables.rb', line 734

def to_sexp
  left = @left ? @left.to_sexp : [:array]
  left << [:splat, @splat.to_sexp] if @splat
  left << @block.to_sexp if @block

  sexp = [:masgn, left]
  sexp << @right.to_sexp if @right
  sexp
end