= tailor

* http://github.com/turboladen/tailor

== DESCRIPTION:

tailor parses Ruby files and measures them with some style and static analysis
"rulers".  Default values for the Rulers are based on a number of style guides
in the Ruby community as well as what seems to be common.  More on this here
http://wiki.github.com/turboladen/tailor.

tailor's goal is to help you be consistent with your style, throughout your
project, whatever style that may be.

== FEATURES/PROBLEMS:

* Checks for bad style in Ruby files
  * Recursively in a directory, or...
  * A given file, or...
  * A glob ('lib/**/*.rb')
* Checks for:
  * Horizontal spacing
    * Indentation
    * Use of hard-tabs
    * Line length
    * Trailing spaces at the end of lines
    * Spacing after commas
    * Spacing before commas
    * Spacing around { and before }
    * Spacing after [ and before ]
    * Spacing after ( and before )
  * Vertical spacing
    * Trailing newlines (at the end of the file)
    * Max code lines in a class/module
    * Max code lines in a method
  * Name cases
    * Snake case class & module names
    * Camel case method names
  * Valid Ruby (warns by default)
* Configurable
  * Specify style in
    * ~./tailorrc
    * PROJECT_ROOT + .tailor
    * as CLI options
  * "File sets" allow for applying different styles to different groups of files
  * Set problems to :warn or :off instead of :fail
* Define custom "Rulers"
* CI/Build Integration
  * (Well, this may be stretching things a bit, but...) Exit 1 on failures

== SYNOPSIS:

=== Why style check?

If you're reading this, there's a good chance you already have your own reasons
for doing so.  If you're not familiar with static analysis, give tailor a go
for a few days and see if you think it improves your code's readability.

=== What's it do?

At tailor's inception, there were some other static analysis tools for Ruby,
but none which checked style stuff; tailor started off as a means to fill this
gap.  Since then, a number of those tools have dropped by the wayside due to
various Ruby 1.9 incompatibilities, and left a bigger tool gap for Rubyists.
Right now it's mostly a style-checker, but might into a tool for analyzing other
aspects of your Ruby code.

=== Since 0.x...

tailor 1.x is a marked improvment over 0.x.  While 0.x provided a few (pretty
inconsistent) style checks, its design made the code get all spaghetti-like,
with lots of really gnarly regular expression matching, making it a realy bear
to add new features and fix bugs.  tailor 1.x is completely redesigned to make
that whole process much easier.

=== Measure Stuff

Run tailor like:

  $ tailor path/to/check/

...or...

  $ tailor file_to_check.rb

...or...

  $ tailor test/**/*.rb

...or... (defaults to lib/**/*.rb):

  $ tailor

==== On style...

The features list, above, shows some aspects of style that should be fairly
straightforward (as to their meaning and reason), however, others make some big
assumptions--particularly the indentation checking "ruler".  There are a number
of popular indenting conventions...  In the case of multi-line parameters to a
method, some like do this:

  def a_really_freakin_long_method_name(my_really_long_first_parameter,
    my_next_param)
    # ...
  end

...while others prefer:

  def a_really_freakin_long_method_name(my_really_long_first_parameter,
      my_next_param)
    # ...
  end

...and yet some others prefer:

  def a_really_freakin_long_method_name(my_really_long_first_parameter,
                                        my_next_param)
    # ...
  end

At this point, tailor only supports the style used in the first example.  If
this style isn't to your liking, then definitely take a look at the
Configurable section here to see how to turn this off.  Other styles will
probably be supported in the future.

All that to say, though, that this isn't the only case where tailor makes style
assumptions.  Another discrepancy in popular styles is with regard to aligning
operators in different lines.  Some like:

  my_hash[:first][:thing] = 1
  my_hash[:eleventy][:thing] = 2

...while others prefer:

  my_hash[:first][:thing]    = 1
  my_hash[:eleventy][:thing] = 2

...and yet some others prefer:

  my_hash[:first][:thing] =    1
  my_hash[:eleventy][:thing] = 2

Again, tailor only supports the first example here.

The goal is certainly not to force you to use the style that tailor currently
uses; it just might not support your style yet.  If tailor doesn't support your
style, please feel free to take a look at the issues list and make a request.
...or fork away!

=== Configurable:

Not everyone prefers the same style of, well, anything really.  tailor is
configurable to allow you to check your code against the style measurements
that you want.

It has default values for each of the "rulers" it uses, but if you want to
customize these, there are a number of ways you can do so.

==== CLI

At any time, you can tell tailor to show you the configuration that it's going
to use by doing:

  $ tailor --show-config

To see, amongst other options, the style options that you can pass in, do

  $ tailor --help

If, for example, you want to tell tailor to warn you if any of your code lines
are > 100 chars (instead of the default of 80):

  $ tailor --max-line-length 100 lib/

If you want to simply disable a ruler, just pass +off+ to the option:

  $ tailor --max-line-length off lib/

==== Configuration File

While you can drive most tailor options from the command line, configuration
files allow for some more flexibility with style rulers, file lists, and
(eventually) report formatters.  To create one with default settings, do:

  $ tailor --create-config

With the documentation that's provided in the file, the settings should be
straightforward (if they're not, please let me know!).  You don't have to specify
all of those settings in your config file--those are just rendered so you have
a starting ground to tweak with.  If you only want to override a single value,
you can delete the rest of the code from your config.  This would accomplish
the same as the <tt>--max-line-length</tt> example above:

  # .tailor
  Tailor.config do |config|
    config.file_set 'lib/**/*.rb' do |style|
      style.max_line_length 100
    end
  end

This brings us to the concept of "file sets"...

===== File Sets

File sets allow you to use different style rulers against different groups of
files.  You may, for example, want your Rails app code to allow for longer
lines, or fewer code lines in methods... You may want your RSpec code to be
more lenient with curly-brace usage... You may just want to specify a few file
globs to use the default set of rulers...  File sets allow for those sorts of
things.

In the default config file, you see a single parameter being passed to
<tt>config.file_set</tt>--this is the glob that defines the list of files for
that file set.  While you don't see it, +config.file_set+ takes a second
optional parameter that allows you to _label_ your style properties, and thus
use different sets of style properties for differet sets of files.  The label is
simply just a name to refer to that file set by; it will show in your report
(in the case that problems were found, of course) so you know what set of
rulers caused the problem to be found.

  # .tailor
  Tailor.config do |config|

    # All defaults; implies "default" label
    config.file_set 'lib/**/*.rb

    config.file_set 'app/**/*.rb', :rails_app do |style|
      style.max_line_length 100
      # All other rulers will use default values
    end

    # Uses default style, but labelled in the report with "features"
    config.file_set 'features/**/*.rb', :features

    config.file_set 'spec/**/*.rb', :rspec do |style|
      style.spaces_after_lbrace false
      style.spaces_before_lbrace false
      style.spaces_before_rbrace false
      # All other rulers will use default values
    end
  end

Similarly to the CLI, if you want to turn off a default Ruler, set its problem
level to +:off+:

  # .tailor
  Tailor.config do |config|
    config.file_set 'lib/**/*.rb do |style|
      style.indentation_spaces 2, level: :off
    end
  end


=== Define A Custom Ruler

While tailor provides a number of Rulers for checking style, it also provides a
way for you to add your own rulers without having to delve into its innards.  To
do this, you need to do the following.

==== Create the Ruler

Before jumping in to this, take a look at {Tailor::Ruler} and any of the
existing Rulers in +lib/tailor/rulers/+.  There are some key things a new Ruler
must have:

* the class name ends with "Ruler"
* it inherits {Tailor::Ruler}
* it's defined within the {Tailor::Rulers} module
* +#initialize+ defines two parameters:
  1. +config+ sets +@config+ to the "golden rule" value for what you're measuring
  2. +options+ is a Hash, that should at least be passed the :level => you want
     the problem to be logged as
* +#add_lexer_observers+ gets passed a list of {Tailor::Lexer} event types that
  the ruler should get notified on
* it defines call-back methods for {Tailor::Lexer} to call when it comes across
  an event of interest
* it calls +#measure+ to assess if the criteria it's checking has been met
* it adds a {Tailor::Problem} to +@problems+ when one is found in +#measure+

==== Add the Ruler to the list of Styles

Internally, this all happens in +lib/tailor/configuration/style.rb+, but you can
add infomation about your ruler to your config file.  If you created a Ruler:

  # max_lines_in_block.rb
  class Tailor
    module Rulers
      class MaxLinesInBlockRuler < Tailor::Ruler
        def initialize(config, options)
          super(config, options)
          add_lexer_observers :ignored_nl, :kw
        end

        def ignored_nl_update(lexed_line, lineno, column)
          # ...
        end

        def kw_update(token, lexed_line, lineno, column)
          # ...
        end

        def measure
          # ...
        end

        # ...
      end
    end
  end

...then require this and add it to the Style list of properties:

  # .tailor
  require 'tailor/configuration/style'
  require 'max_lines_in_block'

  Tailor::Configuration::Style.define_property :max_lines_in_block

  Tailor.config do |config|
    config.file_set 'lib/**/*.rb' do |style|
      style.max_lines_in_block 10, level: :error
    end
  end

Next time you run tailor, your Ruler will get initialized and used.

== REQUIREMENTS:

* Rubies (tested)
  * 1.9.2
  * 1.9.3
* Gems
  * log_switch
  * term-ansicolor
  * text-table

== INSTALL:

  $ (sudo) gem install tailor

== LICENSE:

(The MIT License)

Copyright (c) 2010-2012 Steve Loveless

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
'Software'), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.