Small module to help with DSL evaluation. Notably, it produces a human-friendly backtrace error showing the original user-provided source code if there's a syntax error.

Example usage:

DslEvaluator.configure do |config|
  config.backtrace.reject_pattern = "/lib/lono"
  config.logger = Lono.logger
  config.on_exception = :exit
  config.root = Lono.root
end

class Dsl
  include DslEvaluator
  def build
    path = "/path/to/user/provided/dsl/file.rb"
    evaluate_file(path) # from DslEvaluator module
  end
end

For other libraries where printing the code and context lines around the code is useful, you can use DslEvaluator.print_code.

The print_code method understands "polymorphic" arguments.

1. If the caller line info is part of a standard ruby backtrace line. Example of this is in ufo helpers/ecr.rb

call_line = ufo_config_call_line
DslEvaluator.print_code(call_line)

2. If the caller line info is custom. Example of this is in ufo erb/yaml.rb

path = "replace with path to file"
line_number = "replace with line number. usually can get the exception.message"
DslEvaluator.print_code(path, line_number)

Add this line to your application's Gemfile:

gem 'dsl_evaluator'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install dsl_evaluator

Bug reports and pull requests are welcome on GitHub at https://github.com/tongueroo/dsl_evaluator.

The gem is available as open source under the terms of the MIT License.