110 lines
2.7 KiB
Markdown
110 lines
2.7 KiB
Markdown
# Namarara
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Namarara is a library that parses boolean expressions, builds an [binary
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expression tree](https://en.wikipedia.org/wiki/Binary_expression_tree).
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Namare can also evalutes a result from a set of values corresponding the
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variables used within the boolean expression.
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2. binary expression
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and computes a boolean result from this AST.
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## Installation
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Add this line to your application's Gemfile:
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```ruby
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gem 'namarara'
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```
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And then execute:
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```shell-session
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$ bundle
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```
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Or install it yourself as:
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```shell-session
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$ gem install namarara
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```
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## Usage
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### Evaluate a single expression
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```ruby
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require 'namarara'
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# Initialize Namarara
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namarara = Namarara::Parser.new(Namarara::Lexer.new)
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# Prepare variables
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namarara.names = {
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this: 'true',
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that: 'false',
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other: 'false',
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something_else: 'true'
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}
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# Build a binary expression tree (aka BET) from string
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# and inject values
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exp_tree = namarara.parse('this AND (that OR other) AND something_else')
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# Compute tree with variables
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result = exp_tree.compute
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puts result # = false
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```
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### Evaluating a set of rules
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```ruby
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require 'namarara'
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# Initialize Namarara
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namarara = Namarara::Parser.new(Namarara::Lexer.new)
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# A set of rules i want to check
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# (in this example we are looking for sensitive personnal data)
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rules = {
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vulnerable_person: 'is_adult AND is_subordinate',
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has_constraints: 'is_adult AND has_children',
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is_child: 'NOT is_adult'
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# ...
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}
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# A set of values i want to inject (values must be expressed as strings)
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namarara.names = {
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"is_adult" => 'false',
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"is_subordinate" => 'true',
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"has_children" => 'true'
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}
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results = rules.map { |rule, expr| [rule, namarara.parse(expr).compute] }
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if results.select{ |rule, value| value }.empty?
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puts "Perfect! Nothing to say ;-)"
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else
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puts "Warning: you are collectif sensitive personnal data !"
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results.each do |rule, value|
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puts "#{value ? '>>':' '} #{rule}: #{value}"
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end
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end
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```
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## Development
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After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
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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](https://rubygems.org).
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## Contributing
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Bug reports and pull requests are welcome on GitHub at https://github.com/glenux/namarara
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## License
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The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).
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