FilterLexer

This is a simple treetop implementation for a basic SQL-like filtering syntax.

Installation

Add this line to your application's Gemfile:

gem 'filter_lexer'

And then execute:

bundle

Or install it yourself as:

gem install filter_lexer

Usage

To parse a filter, simply do the following:

tree = FilterLexer::Parser.parse('foo == "BAR"')

If the parsing succeeds, a tree is returned. This tree can be output (for development purposes) using FilterLexer::Parser.output_tree.

If the parsing fails, a ParseException is raised containing the detials of the failure.

Simple complete example showing success and failure:

examples = [
    'foo == "BAR"',
    'foo == "BAR" &&',
]

examples.each do |example|
    begin
        tree = FilterLexer::Parser.parse(example)
        puts "Parsed #{example}"
        FilterLexer::Parser.output_tree(tree)
    rescue FilterLexer::ParseException
        puts $!.message
        puts $!.context
    end
end

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rspec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

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

License

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