Class: Opal::Rewriters::DeduplicateArgName

Inherits:
Base
  • Object
show all
Defined in:
lib/opal/rewriters/deduplicate_arg_name.rb

Overview

Ruby allows for args with the same name, if the arg starts with a '', like: def funny_method_name(, ) puts _ end but JavaScript in strict mode does not allow for args with the same name Ruby assigns the value of the first arg given funny_method_name(1, 2) => 1 leave the first appearance as it is and rename the other ones compiler result: function $$funny_method_name(, __$2)

Constant Summary

Constants inherited from Base

Base::DUMMY_LOCATION

Instance Attribute Summary

Attributes inherited from Base

#current_node

Instance Method Summary collapse

Methods inherited from Base

#append_to_body, #begin_with_stmts, #dynamic!, #error, #on_top, #prepend_to_body, #process, s, #s, #stmts_of

Instance Method Details

#on_args(node) ⇒ Object 



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# File 'lib/opal/rewriters/deduplicate_arg_name.rb', line 16

def on_args(node)
  @arg_name_count = Hash.new(0)

  children = node.children.map do |arg|
    rename_arg(arg)
  end

  super(node.updated(nil, children))
end

#rename_arg(arg) ⇒ Object 



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# File 'lib/opal/rewriters/deduplicate_arg_name.rb', line 26

def rename_arg(arg)
  case arg.type
  when :arg, :restarg, :kwarg, :kwrestarg, :blockarg
    name = arg.children[0]
    name ? arg.updated(nil, [unique_name(name)]) : arg
  when :optarg, :kwoptarg
    name, value = arg.children
    arg.updated(nil, [unique_name(name), value])
  when :mlhs
    new_children = arg.children.map { |child| rename_arg(child) }
    arg.updated(nil, new_children)
  else
    arg
  end
end

#unique_name(name) ⇒ Object 



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# File 'lib/opal/rewriters/deduplicate_arg_name.rb', line 42

def unique_name(name)
  count = (@arg_name_count[name] += 1)
  count > 1 ? :"#{name}_$#{count}" : name
end