Class: Ruport::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/ruport/parser.rb

Overview

If you’re reporting on data, there is a good chance it’s going to need some munging. A 100% compatible modified version of JEG2’s Parse::Input, Ruport::Parser can help you do that.

This class provides a system that lets you specify regular expressions to identify patterns and extract the data you need from your input.

It implements a somewhat straightforward domain specific language to help you scrape and tear up your gnarly input and get something managable.

It is a bit of an expert tool, but is indispensible when messy data needs to be parsed. For now, you’ll probably want to read the source for this particular class. There may be dragons.

Sample usage:

path = "somefile"
data = Ruport::Parser.new(path, "") do
  @state = :skip
  stop_skipping_at("Save Ad")
  skip(/\A\s*\Z/)

  pre { @price = @miles = nil }
  read(/\$([\d,]+\d)/) { |price| @price = price.delete(",").to_i }
  read(/([\d,]*\d)\s*m/) { |miles| @miles = miles.delete(",").to_i }

  read do |ad|
    if @price and @price < 20_000 and @miles and @miles < 40_000
      (@ads ||= Array.new) << ad.strip
    end
  end
end

Instance Method Summary collapse

Constructor Details

#initialize(path, separator = $/, &init) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/ruport/parser.rb', line 71

def initialize( path, separator = $/, &init )
  @path      = path
  @separator = separator
  @state     = :read

  @_pre_readers   = Array.new
  @_readers       = Array.new
  @_post_readers  = Array.new
  @_skip_starters = Array.new
  @_skip_stoppers = Array.new
  @_skips         = Array.new
  @_skip_searches = Array.new
  @_stops         = Array.new
  @_origin        = :file  
  instance_eval(&init) unless init.nil?

  parse
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object 



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# File 'lib/ruport/parser.rb', line 99

def method_missing( method, *args, &block )
  variable_name = "@#{method}"
  if instance_variables.include? variable_name
    instance_variable_get(variable_name)
  else
    super
  end
end

Instance Method Details

#[](name) ⇒ Object 



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# File 'lib/ruport/parser.rb', line 90

def []( name )
  variable_name = "@#{name}"
  if instance_variables.include? variable_name
    instance_variable_get(variable_name)
  else
    nil
  end
end