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Class: Opal::Nodes::MassAssignNode

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

Constant Summary

SIMPLE_ASSIGNMENT =
%i[lvasgnivasgnlvargvasgncdeclcasgn].freeze

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 , #class_variable_owner_nesting_level , #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

#compileObject

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# File 'opal/lib/opal/nodes/masgn.rb', line 13
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

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# File 'opal/lib/opal/nodes/masgn.rb', line 82
def compile_assignment(child, array, idx, len = nil)
 assign =
 if !len || idx >= len
 s(:js_tmp, "(#{array}[#{idx}] == null ? nil : #{array}[#{idx}])")
 else
 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

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# File 'opal/lib/opal/nodes/masgn.rb', line 41
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

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