ext/curses/view2.rb: replaced with Hugh Sasse's version.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@26603 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/curses/view2.rb

@@ -2,16 +2,22 @@
 
 require "curses"
 
-if ARGV.size != 1 then
+
-  printf("usage: view file\n");
+# A curses based file viewer
-  exit
+class FileViewer
-end
+
-begin
+  # Create a new fileviewer, and view the file.
-  fp = open(ARGV[0], "r")
+  def initialize(filename)
-rescue
+    @data_lines = []
-  raise "cannot open file: #{ARGV[1]}"
+    @screen = nil
+    @top = nil
+    init_curses
+    load_file(filename)
+    interact
   end
 
+  # Perform the curses setup
+  def init_curses
     # signal(SIGINT, finish)
 
     Curses.init_screen
@@ -19,34 +25,42 @@ Curses.nonl
     Curses.cbreak
     Curses.noecho
 
-$screen = Curses.stdscr
+    @screen = Curses.stdscr
 
-$screen.scrollok(true)
+    @screen.scrollok(true)
     #$screen.keypad(true)
+  end
 
+  # Load the file into memory, and put
+  # the first part on the curses display.
+  def load_file(filename)
+    fp = open(filename, "r") do |fp|
     # slurp the file
-$data_lines = []
     fp.each_line { |l|
-  $data_lines.push(l.chop)
+      @data_lines.push(l.chop)
     }
-fp.close
+    end
-
+    @top = 0
-$top = 0
+    @data_lines[0..@screen.maxy-1].each_with_index{|line, idx|
-$data_lines[0..$screen.maxy-1].each_with_index{|line, idx|
+      @screen.setpos(idx, 0)
-  $screen.setpos(idx, 0)
+      @screen.addstr(line)
-  $screen.addstr(line)
     }
-$screen.setpos(0,0)
+    @screen.setpos(0,0)
-$screen.refresh
+    @screen.refresh
+  rescue
+    raise "cannot open file '#{filename}' for reading"
+  end
 
+
+  # Scroll the display up by one line
   def scroll_up
-  if( $top > 0 )
+    if( @top > 0 )
-    $screen.scrl(-1)
+      @screen.scrl(-1)
-    $top -= 1
+      @top -= 1
-    str = $data_lines[$top]
+      str = @data_lines[@top]
       if( str )
-      $screen.setpos(0, 0)
+        @screen.setpos(0, 0)
-      $screen.addstr(str)
+        @screen.addstr(str)
       end
       return true
     else
@@ -54,14 +68,15 @@ def scroll_up
     end
   end
 
+  # Scroll the display down by one line
   def scroll_down
-  if( $top + $screen.maxy < $data_lines.length )
+    if( @top + @screen.maxy < @data_lines.length )
-    $screen.scrl(1)
+      @screen.scrl(1)
-    $top += 1
+      @top += 1
-    str = $data_lines[$top + $screen.maxy - 1]
+      str = @data_lines[@top + @screen.maxy - 1]
       if( str )
-      $screen.setpos($screen.maxy - 1, 0)
+        @screen.setpos(@screen.maxy - 1, 0)
-      $screen.addstr(str)
+        @screen.addstr(str)
       end
       return true
     else
@@ -69,16 +84,22 @@ def scroll_down
     end
   end
 
+  # Allow the user to interact with the display.
+  # This uses EMACS-like keybindings, and also
+  # vi-like keybindings as well, except that left
+  # and right move to the beginning and end of the
+  # file, respectively.
+  def interact
     while true
       result = true
       c = Curses.getch
       case c
-  when Curses::KEY_DOWN, Curses::KEY_CTRL_N
+      when Curses::KEY_DOWN, Curses::KEY_CTRL_N, ?j
         result = scroll_down
-  when Curses::KEY_UP, Curses::KEY_CTRL_P
+      when Curses::KEY_UP, Curses::KEY_CTRL_P, ?k
         result = scroll_up
       when Curses::KEY_NPAGE, ?\s  # white space
-    for i in 0..($screen.maxy - 2)
+        for i in 0..(@screen.maxy - 2)
           if( ! scroll_down )
             if( i == 0 )
               result = false
@@ -87,7 +108,7 @@ while true
           end
         end
       when Curses::KEY_PPAGE
-    for i in 0..($screen.maxy - 2)
+        for i in 0..(@screen.maxy - 2)
           if( ! scroll_up )
             if( i == 0 )
               result = false
@@ -95,21 +116,34 @@ while true
             break
           end
         end
-  when Curses::KEY_LEFT, Curses::KEY_CTRL_T
+      when Curses::KEY_LEFT, Curses::KEY_CTRL_T, ?h
         while( scroll_up )
         end
-  when Curses::KEY_RIGHT, Curses::KEY_CTRL_B
+      when Curses::KEY_RIGHT, Curses::KEY_CTRL_B, ?l
         while( scroll_down )
         end
       when ?q
         break
       else
-    $screen.setpos(0,0)
+        @screen.setpos(0,0)
-    $screen.addstr("[unknown key `#{Curses.keyname(c)}'=#{c}] ")
+        @screen.addstr("[unknown key `#{Curses.keyname(c)}'=#{c}] ")
       end
       if( !result )
         Curses.beep
       end
-  $screen.setpos(0,0)
+      @screen.setpos(0,0)
     end
     Curses.close_screen
+  end
+end
+
+
+# If we are being run as a main program...
+if __FILE__ == $0
+  if ARGV.size != 1 then
+    printf("usage: #{$0} file\n");
+    exit
+  end
+
+  viewer = FileViewer.new(ARGV[0])
+end