Processr¶ ↑

• Overview

• Installation

• Usage

• Bugs

Processr is a simple text processing and concatenation library. It takes a number of input strings (or files) and outputs a single string (or file) containing the result. Text can be passed through filters to modify the output.

The project is hosted on rubygems.org. Getting it is simple:

gem install processr

Use the configuration block to setup Processr

Processr.configure do |config|
  config.root = File.expand_path(File.dirname(__FILE__))
  config.out  = File.join(config.root, 'output.txt')
end

If an output file is specified the result will be written to that file, otherwise the result will be returned directly from the #process! method.

processor = Processr.new
processor << "Some\n"
processor << "Text"
processor.process! # => "Some\nText"

This will result in a concatenated string being returned.

processor = Processr.new
processor.files << 'input_one.txt'
processor.files << 'input_two.txt'
processor.process! # => contents of input_one.txt and input_two.txt

This will result in the contents of input_one.txt and input_two.txt returned.

Filters can be used to modify the output of a processing session. A filter is any object that responds to #call. Filters take a single argument (the input buffer) and must return the modified buffer for further processing. For example:

lambda do |buffer|
  # ...do something with buffer here...

  buffer
end

Or

class MyFilter

  def self.call(buffer)
    # ...do something with buffer here...

    buffer
  end

end

You can register a filter by calling #add_filter on an instance of Processr. A further example would be a really simple textile parser:

TextileFilter = lambda do |buffer|

  lookup = {
    /_(.*)_/         => '<em>\1</em>',
    /\*(.*)\*/       => '<strong>\1</strong>',
    /\"(.*)\":(\S*)/ => '<a href="\2">\1</a>'
  }

  lookup.each_pair do |regex, replacement|
    buffer.gsub!(regex, replacement)
  end

  buffer
end

processor = Processr.new
processor.add_filter(TextileFilter)
processor << 'A _simple_ example of a "textile":http://www.textism.com/tools/textile/ parser using a *filter*.'
processor.process! # => "A <em>simple</em> example of a <a href="http://www.textism.com/tools/textile/">textile</a> parser using a <strong>filter</strong>."

You can also add filters to be run when a file is read to the buffer. This behaves similarly to a normal filter, and must return the file contents to the buffer:

InBetweenFilter = lambda do |filename, contents|
  puts "Filter for #{filename}"
  contents
end

processor = Processr.new
processor.add_file_filter(InBetweenFilter)
processor.files << File.join('..', 'spec', 'fixtures', 'one.txt')
processor.files << File.join('..', 'spec', 'fixtures', 'two.txt')
puts processor.process! => Filter for ../spec/fixtures/one.txt etc...

Run the examples for more information.

If you have any problems with processr, please file an issue at github.com/joshnesbitt/processr/issues.

• Fork the project.

• Make your feature addition or bug fix.

• Add tests for it. This is important so I don’t break it in a future version unintentionally.

• Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

• Send me a pull request. Bonus points for topic branches.

Copyright © 2010 Josh Nesbitt <josh@josh-nesbitt.net>. See LICENSE for details.