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

3 files changed, 211 insertions, 12 deletions

diff --git a/MANIFEST b/MANIFEST
index 32294deb09..153b205c33 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -262,6 +262,7 @@ lib/rdoc/parsers/parserfactory.rb
 lib/rdoc/ri/ri_cache.rb
 lib/rdoc/ri/ri_descriptions.rb
 lib/rdoc/ri/ri_formatter.rb
+lib/rdoc/ri/ri_options.rb
 lib/rdoc/ri/ri_paths.rb
 lib/rdoc/ri/ri_reader.rb
 lib/rdoc/ri/ri_util.rb
diff --git a/bin/ri b/bin/ri
index c9c3abc4ad..4103f3a7a8 100755
--- a/bin/ri
+++ b/bin/ri
@@ -16,6 +16,7 @@ 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'
 
 ######################################################################
 
@@ -33,19 +34,50 @@ end
 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 "\nIs ri correctly installed?"
+      $stderr.puts "\nWas rdoc run to create documentation?"
       exit 1                   
     end
     @ri_reader = RI::RiReader.new(RI::RiCache.new(paths))
-    @formatter = RI::RiFormatter.new(72, "     ")
+    @formatter = RI::RiFormatter.new(@options.width, "     ")
   end    
   
+  
+  ######################################################################
+
+  def setup_pager
+    require 'tempfile'
+
+    @save_stdout = STDOUT.clone
+    STDOUT.reopen(Tempfile.new("ri_"))
+  end
+
+  ######################################################################
+
+  def page_output
+    path = STDOUT.path
+    STDOUT.reopen(@save_stdout)
+    @save_stdout = nil
+    paged = false
+    for pager in [ ENV['pager'], "less", "more <" ].compact.uniq
+      if system("#{pager} #{path}")
+        paged = true
+        break
+      end
+    end
+    if !paged
+      @options.use_stdout = true
+      puts File.read(path)
+    end
+  end
+
   ######################################################################
   
   def display_params(method)
@@ -175,18 +207,26 @@ def display_info_for(arg)
     end
   end
 
-  if desc.method_name.nil?
-    report_class_stuff(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}")
+  setup_pager unless @options.use_stdout
+  
+  begin
+    if desc.method_name.nil?
+      report_class_stuff(namespaces)
     else
-      report_method_stuff(desc.method_name, methods)
+      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 unless @options.use_stdout
+  ensure
+    STDOUT.reopen(@save_stdout) if @save_stdout
   end
     
 end
diff --git a/lib/rdoc/ri/ri_options.rb b/lib/rdoc/ri/ri_options.rb
new file mode 100644
index 0000000000..3ec6d4657c
--- /dev/null
+++ b/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
+