Add pager support to ri, and start implementing command line options

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@5205 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rdoc/ri/ri_options.rb

@@ -0,0 +1,158 @@
+# We handle the parsing of options, and subsequently as a singleton
+# object to be queried for option values
+
+module RI
+
+  VERSION_STRING = "alpha 0.1"
+
+  class Options
+    
+    require 'singleton'
+    require 'getoptlong'
+    
+    include Singleton
+
+    # No not use a pager. Writable, because ri sets it if it
+    # can't find a pager
+    attr_accessor :use_stdout
+
+    # The width of the output line
+    attr_reader :width
+    
+    module OptionList
+      
+      OPTION_LIST = [
+        [ "--help",          "-h",   nil,
+         "you're looking at it" ],
+             
+        [ "--no-pager",      "-T",   nil,
+          "Send output directly to stdout." 
+        ],
+
+        [ "--width",         "-w",   "output width",
+        "set the width of the output" ],
+
+      ]
+
+      def OptionList.options
+        OPTION_LIST.map do |long, short, arg,|
+          [ long, 
+           short, 
+           arg ? GetoptLong::REQUIRED_ARGUMENT : GetoptLong::NO_ARGUMENT 
+          ]
+        end
+      end
+
+
+      def OptionList.strip_output(text)
+        text =~ /^\s+/
+        leading_spaces = $&
+        text.gsub!(/^#{leading_spaces}/, '')
+        $stdout.puts text
+      end
+      
+      
+      # Show an error and exit
+      
+      def OptionList.error(msg)
+        $stderr.puts
+        $stderr.puts msg
+        $stderr.puts "\nFor help on options, try 'ri --help'\n\n"
+        exit 1
+      end
+      
+      # Show usage and exit
+      
+      def OptionList.usage
+        
+        puts
+        puts(RI::VERSION_STRING)
+        puts
+        
+        name = File.basename($0)
+        OptionList.strip_output(<<-EOT)
+          Usage:
+
+            #{name} [options]  [names...]
+
+          Display information on Ruby classes, modules, and methods.
+          Give the names of classes or methods to see their documentation.
+          Partial names may be given: if the names match more than
+          one entity, a list will be shown, otherwise details on
+          that entity will be displayed.
+
+          Nested classes and modules can be specified using the normal
+          Name::Name notation, and instance methods can be distinguished
+          from class methods using "." (or "#") instead of "::".
+
+          For example:
+
+              ri  File
+              ri  File.new
+              ri  F.n
+              ri  zip
+
+          Note that shell quoting may be required for method names
+          containing puncuation:
+
+              ri 'Array.[]'
+              ri compact\!
+
+          Options:
+
+      EOT
+                                
+        OPTION_LIST.each do |long, short, arg, desc|
+          opt = sprintf("%20s", "#{long}, #{short}")
+          oparg = sprintf("%-7s", arg)
+          print "#{opt} #{oparg}"
+          desc = desc.split("\n")
+          if arg.nil? || arg.length < 7  
+            puts desc.shift
+          else
+            puts
+          end
+          desc.each do |line|
+            puts(" "*28 + line)
+          end
+          puts
+        end
+
+        exit 0
+      end
+  end
+
+    # Parse command line options.
+
+    def parse
+
+      @use_stdout = !STDOUT.tty?
+      @width = 72
+      
+      begin
+        
+        go = GetoptLong.new(*OptionList.options)
+        go.quiet = true
+        
+        go.each do |opt, arg|
+          case opt
+          when "--help"      then OptionList.usage
+          when "--no-pager"  then @use_stdout = true
+          when "--width"
+            begin
+              @width = Integer(arg)
+            rescue 
+              $stderr.puts "Invalid width: '#{arg}'"
+              exit 1
+            end
+          end
+        end
+        
+      rescue GetoptLong::InvalidOption, GetoptLong::MissingArgument => error
+        OptionList.error(error.message)
+        
+      end
+    end
+  end
+end
+