synvert-core-ruby

Synvert core provides a set of DSLs to rewrite ruby code. e.g.

Synvert::Rewriter.new 'ruby', 'map_and_flatten_to_flat_map' do
  description <<~EOS
    It converts `map` and `flatten` to `flat_map`

    ```ruby
    enum.map do
      # do something
    end.flatten
    ```

    =>

    ```ruby
    enum.flat_map do
      # do something
    end
    ```
  EOS

  within_files Synvert::ALL_RUBY_FILES do
    with_node type: 'send', receiver: { type: 'block', caller: { type: 'send', message: 'map' } }, message: 'flatten', arguments: { size: 0 } do
      delete :message, :dot
      replace 'receiver.caller.message', with: 'flat_map'
    end
  end
end

Want to see more examples, check out synvert-snippets-ruby.

Want to use the CLI, check out synvert-ruby.

DSLs are as follows

• description - set description of the rewriter
• if_ruby - check if ruby version is greater than or equal to the specified ruby version
• if_gem - compare version of specified gem
• within_files - find specified files
• within_file - alias to within_files
• add_file - add a new file
• remove_file - remove a file
• helper_method - define a helper method
• add_snippet - call another rewriter
• todo - set todo
• redo_until_no_change - run the snippet until no change

Scopes:

• within_node - recursively find matching ast nodes
• with_node - alias to within_node
• goto_node - go to a child node

Conditions:

• if_exist_node - check if matching node exist in the child nodes
• unless_exist_node - check if matching node doesn't exist in the child nodes
• if_only_exist_node - check if current node has only one child node and the child node matches rules

Actions:

• append - append the code to the bottom of current node body
• prepend - prepend the code to the bottom of current node body
• insert - insert code
• insert_after - insert the code next to the current node
• replace - replace the code of specified child nodes
• delete - delete the code specified child nodes
• wrap - wrap the current node with code
• replace_with - replace the whole code of current node
• warn - warn message
• replace_erb_stmt_with_expr - replace erb stmt code to expr code