ruby--ruby/bin/ri

#!/usr/bin/env ruby
# usage:
#
#   ri  name...
#
# where name can be 
#
#   Class | Class::method | Class#method | Class.method | method
#
# All names may be abbreviated to their minimum unbiguous form. If a name
# _is_ ambiguous, all valid options will be listed.
#
# The form '.' method matches either class or instance methods, while 
# #method matches only instance and ::method matches only class methods.

require 'rdoc/ri/ri_paths'
require 'rdoc/ri/ri_cache'
require 'rdoc/ri/ri_util'
require 'rdoc/ri/ri_reader'
require 'rdoc/ri/ri_formatter'
require 'rdoc/ri/ri_options'


######################################################################

class  RiDisplay

  def initialize
    @options = RI::Options.instance
    @options.parse
    paths = RI::Paths::PATH
    if paths.empty?
      $stderr.puts "No ri documentation found in:"
      [ RI::Paths::SYSDIR, RI::Paths::SITEDIR, RI::Paths::HOMEDIR].each do |d|
        $stderr.puts "     #{d}"
      end
      $stderr.puts "\nWas rdoc run to create documentation?"
      exit 1                   
    end
    @ri_reader = RI::RiReader.new(RI::RiCache.new(paths))
    @formatter = @options.formatter.new(@options, "     ")
  end    
  
  
  ######################################################################
  
  def display_usage
    setup_pager
    RI::Options::OptionList.usage(short_form=true)
    page_output
  end

  ######################################################################

  def setup_pager
    unless @options.use_stdout
      require 'tempfile'

      @save_stdout = STDOUT.clone
      STDOUT.reopen(Tempfile.new("ri_"))
    end
  end

  ######################################################################

  def page_output
    unless @options.use_stdout
      path = STDOUT.path
      STDOUT.reopen(@save_stdout)
      @save_stdout = nil
      paged = false
      for pager in [ ENV['PAGER'], "less", "more <", 'pager' ].compact.uniq
        if system("#{pager} #{path}")
          paged = true
          break
        end
      end
      if !paged
        @options.use_stdout = true
        puts File.read(path)
      end
    end
  end

  ######################################################################
  
  def display_params(method)

    params = method.params

    if params[0,1] == "("
      if method.is_singleton
        params = method.full_name + params
      else
        params = method.name + params
      end
    end
    params.split(/\n/).each {|p| @formatter.wrap(p) }
  end

  ######################################################################
  
  def display_flow(flow)
    if !flow || flow.empty?
      @formatter.wrap("(no description...)")
    else
      @formatter.display_flow(flow)
    end
  end

  ######################################################################
  
  def display_method_info(method_entry)
    method = @ri_reader.get_method(method_entry)
    @formatter.draw_line(method.full_name)
    display_params(method)
    @formatter.draw_line
    display_flow(method.comment)
    if method.aliases && !method.aliases.empty?
      @formatter.blankline
      aka = "(also known as "
      aka << method.aliases.map {|a| a.name }.join(", ") 
      aka << ")"
      @formatter.wrap(aka)
    end
  end
  
  ######################################################################
  
  def display_class_info(class_entry)
    klass = @ri_reader.get_class(class_entry)
    superclass = klass.superclass_string
    
    if superclass
      superclass = " < " + superclass
    else
      superclass = ""
    end
    
    @formatter.draw_line(klass.display_name + ": " +
                         klass.full_name + superclass)
    
    display_flow(klass.comment)
    @formatter.draw_line
    
    unless klass.includes.empty?
      @formatter.blankline
      @formatter.display_heading("Includes:", 2, "")
      incs = []
      klass.includes.each do |inc|
        inc_desc = @ri_reader.find_class_by_name(inc.name)
        if inc_desc
          str = inc.name + "("
          str << inc_desc.instance_methods.map{|m| m.name}.join(", ")
          str << ")"
          incs << str
        else
          incs << inc.name
        end
      end
    @formatter.wrap(incs.sort.join(', '))
    end
    
    unless klass.constants.empty?
      @formatter.blankline
      @formatter.display_heading("Constants:", 2, "")
      len = 0
      klass.constants.each { |c| len = c.name.length if c.name.length > len }
      len += 2
      klass.constants.each do |c|
        @formatter.wrap(c.value, 
                        @formatter.indent+((c.name+":").ljust(len)))
      end 
    end
    
    unless klass.class_methods.empty?
      @formatter.blankline
      @formatter.display_heading("Class methods:", 2, "")
      @formatter.wrap(klass.class_methods.map{|m| m.name}.sort.join(', '))
    end
    
    unless klass.instance_methods.empty?
      @formatter.blankline
      @formatter.display_heading("Instance methods:", 2, "")
      @formatter.wrap(klass.instance_methods.map{|m| m.name}.sort.join(', '))
    end
    
    unless klass.attributes.empty?
      @formatter.blankline
      @formatter.wrap("Attributes:", "")
      @formatter.wrap(klass.attributes.map{|a| a.name}.sort.join(', '))
    end
  end
  
  ######################################################################
  
  # If the list of matching methods contains exactly one entry, or
  # if it contains an entry that exactly matches the requested method,
  # then display that entry, otherwise display the list of
  # matching method names
  
  def report_method_stuff(requested_method_name, methods)
    if methods.size == 1
      display_method_info(methods[0])
    else
      entries = methods.find_all {|m| m.name == requested_method_name}
      if entries.size == 1
        display_method_info(entries[0])
      else
        puts "More than one method matched your request. You can refine"
        puts "your search by asking for information on one of:\n\n"
        @formatter.wrap(methods.map {|m| m.full_name} .join(", "))
      end
    end
  end
  
  ######################################################################
  
  def report_class_stuff(requested_class_name, namespaces)
    if namespaces.size == 1
      display_class_info(namespaces[0])
    else 
      entries = namespaces.find_all {|m| m.full_name == requested_class_name}
      if entries.size == 1
        display_class_info(entries[0])
      else
        puts "More than one class or module matched your request. You can refine"
        puts "your search by asking for information on one of:\n\n"
        @formatter.wrap(namespaces.map {|m| m.full_name}.join(", "))
      end
    end
  end
  
  ######################################################################
  
  
  def display_info_for(arg)
    desc = NameDescriptor.new(arg)
    
    namespaces = @ri_reader.top_level_namespace
    
    for class_name in desc.class_names
      namespaces = @ri_reader.lookup_namespace_in(class_name, namespaces)
      if namespaces.empty?
        raise RiError.new("Nothing known about #{arg}")
      end
    end
    
    setup_pager
    
    begin
      if desc.method_name.nil?
        report_class_stuff(desc.class_names.join('::'), namespaces)
      else
        methods = @ri_reader.find_methods(desc.method_name, 
                                          desc.is_class_method,
                                          namespaces)
        
        if methods.empty?
          raise RiError.new("Nothing known about #{arg}")
        else
          report_method_stuff(desc.method_name, methods)
        end
      end
      
      page_output
    ensure
      STDOUT.reopen(@save_stdout) if @save_stdout
    end
    
  end

  ######################################################################

  def process_args
    if @options.list_classes
      display_class_list
    else
      if ARGV.size.zero?
        display_usage
      else
        begin
          ARGV.each do |arg|
            display_info_for(arg)
          end
        rescue RiError => e
          $stderr.puts(e.message)
          exit(1)
        end
      end
    end
  end

  ######################################################################

  def display_class_list
    classes = @ri_reader.class_names
    if classes.empty?
      puts "Before using ri, you need to generate documentation"
      puts "using 'rdoc' with the --ri option"
    else
      setup_pager
      @formatter.draw_line("Known classes and modules")
      @formatter.blankline
      @formatter.wrap(@ri_reader.class_names.sort.join(", "))
      page_output
    end
  end

end  # class RiDisplay

######################################################################

ri = RiDisplay.new
ri.process_args