Class: Opal::Nodes::MassAssignNode

Inherits:
Base
  • Object
show all
Defined in:
opal/lib/opal/nodes/masgn.rb

Constant Summary

SIMPLE_ASSIGNMENT = 
[:lvasgn, :ivasgn, :lvar, :gvasgn, :cdecl, :casgn]

Instance Attribute Summary

Attributes inherited from Base

#compiler, #type

Instance Method Summary collapse

Methods inherited from Base

#add_gvar, #add_ivar, #add_local, #add_temp, #children, children, #class_variable_owner, #closest_module_node, #comments, #compile_to_fragments, #error, #expr, #expr?, #expr_or_nil, #fragment, handle, handlers, #has_rescue_else?, #helper, #in_ensure, #in_ensure?, #in_while?, #initialize, #process, #push, #recv, #recv?, #s, #scope, #stmt, #stmt?, truthy_optimize?, #unshift, #while_loop, #with_temp, #wrap

Methods included from Helpers

#conditional_send, #current_indent, #empty_line, #indent, #js_falsy, #js_truthy, #js_truthy_optimize, #line, #mid_to_jsid, #property, #valid_name?

Constructor Details

This class inherits a constructor from Opal::Nodes::Base

Instance Method Details

#compile ⇒ Object 



12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
 
# File 'opal/lib/opal/nodes/masgn.rb', line 12

def compile
  array = scope.new_temp

  if rhs.type == :array
    push "#{array} = ", expr(rhs)
    rhs_len = rhs.children.any? { |c| c.type == :splat } ? nil : rhs.children.size
    compile_masgn(lhs.children, array, rhs_len)
    push ", #{array}" # a mass assignment evaluates to the RHS
  elsif rhs.type == :begin
    retval = scope.new_temp
    push "#{retval} = ", expr(rhs)
    push ", #{array} = Opal.to_ary(#{retval})"
    compile_masgn(lhs.children, array)
    push ", #{retval}"
    scope.queue_temp(retval)
  else
    retval = scope.new_temp
    push "#{retval} = ", expr(rhs)
    push ", #{array} = Opal.to_ary(#{retval})"
    compile_masgn(lhs.children, array)
    push ", #{retval}"
    scope.queue_temp(retval)
  end

  scope.queue_temp(array)
end

#compile_assignment(child, array, idx, len = nil) ⇒ Object 



81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
 
# File 'opal/lib/opal/nodes/masgn.rb', line 81

def compile_assignment(child, array, idx, len = nil)
  if !len || idx >= len
    assign = s(:js_tmp, "(#{array}[#{idx}] == null ? nil : #{array}[#{idx}])")
  else
    assign = s(:js_tmp, "#{array}[#{idx}]")
  end

  part = child.updated
  if SIMPLE_ASSIGNMENT.include?(child.type)
    part = part.updated(nil, part.children + [assign])
  elsif child.type == :send
    part = part.updated(nil, part.children + [assign])
  elsif child.type == :attrasgn
    part.last << assign
  elsif child.type == :mlhs
    # nested destructuring
    tmp = scope.new_temp
    push ", (#{tmp} = Opal.to_ary(#{assign.children[0]})"
    compile_masgn(child.children, tmp)
    push ')'
    scope.queue_temp(tmp)
    return
  else
    raise "Bad child node in masgn LHS: #{child}. LHS: #{lhs}"
  end

  push ', '
  push expr(part)
end

#compile_masgn(lhs_items, array, len = nil) ⇒ Object

'len' is how many rhs items are we sure we have



40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
 
# File 'opal/lib/opal/nodes/masgn.rb', line 40

def compile_masgn(lhs_items, array, len = nil)
  pre_splat  = lhs_items.take_while { |child| child.type != :splat }
  post_splat = lhs_items.drop(pre_splat.size)

  pre_splat.each_with_index do |child, idx|
    compile_assignment(child, array, idx, len)
  end

  unless post_splat.empty?
    splat = post_splat.shift

    if post_splat.empty? # trailing splat
      if part = splat.children[0]
        part = part.dup << s(:js_tmp, "$slice.call(#{array}, #{pre_splat.size})")
        push ', '
        push expr(part)
      end
    else
      tmp = scope.new_temp # end index for items consumed by splat
      push ", #{tmp} = #{array}.length - #{post_splat.size}"
      push ", #{tmp} = (#{tmp} < #{pre_splat.size}) ? #{pre_splat.size} : #{tmp}"

      if part = splat.children[0]
        part = part.dup << s(:js_tmp, "$slice.call(#{array}, #{pre_splat.size}, #{tmp})")
        push ', '
        push expr(part)
      end

      post_splat.each_with_index do |child, idx|
        if idx == 0
          compile_assignment(child, array, tmp)
        else
          compile_assignment(child, array, "#{tmp} + #{idx}")
        end
      end

      scope.queue_temp(tmp)
    end
  end
end