Class: Tb::Pager

Inherits:
Object
  • Object
show all
Defined in:
lib/tb/pager.rb

Constant Summary collapse

DEFAULT_LINES = 
24
DEFAULT_COLUMNS = 
80

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Pager

Returns a new instance of Pager.



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# File 'lib/tb/pager.rb', line 16

def initialize
  if $stdout.tty?
    @io = nil
    @buf = ''
  else
    @io = $stdout
    @buf = nil
  end
end

Class Method Details

.open ⇒ Object 



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# File 'lib/tb/pager.rb', line 7

def self.open
  pager = self.new
  begin
    yield pager
  ensure
    pager.close
  end
end

Instance Method Details

#<<(obj) ⇒ Object 



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# File 'lib/tb/pager.rb', line 26

def <<(obj)
  write obj.to_s
  self
end

#close ⇒ Object 



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# File 'lib/tb/pager.rb', line 123

def close
  if !@io
    $stdout.print @buf
  else
    # don't need to ouput @buf because @buf is nil.
    @io.close if @io != $stdout
  end
  nil
end

#expand_tab(str, tabstop = 8) ⇒ Object 



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# File 'lib/tb/pager.rb', line 69

def expand_tab(str, tabstop=8)
  col = 0
  str.gsub(/(\t+)|[^\t]+/) {
    if $1
      ' ' * (($1.length * tabstop) - (col + 1) % tabstop)
    else
      $&
    end
  }
end

#flush ⇒ Object 



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# File 'lib/tb/pager.rb', line 118

def flush
  @io.flush if @io
  self
end

#print(*args) ⇒ Object 



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# File 'lib/tb/pager.rb', line 31

def print(*args)
  s = ''
  args.map {|a| s << a.to_s }
  write s
  nil
end

#printf(format, *args) ⇒ Object 



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# File 'lib/tb/pager.rb', line 38

def printf(format, *args)
  write sprintf(format, *args)
  nil
end

#putc(ch) ⇒ Object 



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# File 'lib/tb/pager.rb', line 43

def putc(ch)
  if Integer === ch
    write [ch].pack("C")
  else
    write ch.to_s
  end
  ch
end

#puts(*objs) ⇒ Object 



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# File 'lib/tb/pager.rb', line 52

def puts(*objs)
  if objs.empty?
    write "\n"
  else
    objs.each {|o|
      o = o.to_s
      write o
      write "\n" if /\n\z/ !~ o
    }
  end
  nil
end

#single_screen?(str) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tb/pager.rb', line 91

def single_screen?(str)
  lines, columns = winsize
  n = 0
  str.each_line {|line|
    line = expand_tab(line).chomp
    cols = line.length # xxx: 1 column/character assumed.
    cols = 1 if cols == 0
    m = (cols + columns - 1) / columns # termcap am capability is assumed.
    n += m
  }
  n <= lines-1
end

#winsize ⇒ Object 



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# File 'lib/tb/pager.rb', line 83

def winsize
  if $stdout.respond_to? :winsize
    lines, columns = $stdout.winsize
    return [lines, columns] if lines != 0 && columns != 0
  end
  [DEFAULT_LINES, DEFAULT_COLUMNS]
end

#write(str) ⇒ Object 



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# File 'lib/tb/pager.rb', line 104

def write(str)
  str = str.to_s
  if !@io
    @buf << str
    if !single_screen?(@buf)
      @io = IO.popen(ENV['PAGER'] || 'more', 'w')
      @io << @buf
      @buf = nil
    end
  else
    @io << str
  end
end

#write_nonblock(str) ⇒ Object 



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# File 'lib/tb/pager.rb', line 65

def write_nonblock(str)
  write str.to_s
end