--
-- $Header: /Users/dap/lua/RCS/ScratchIO.lua,v 1.1 2007/02/11 08:40:26 dap Exp $
--
-- Author (a) 2007, Damon Anton Permezel.  All bugs revered.
--
-- scratch.lua - source this in some VoodooPad scripts
--
-- Usage:
--[[

package.path = package.path .. ';/Users/dap/lua/?.lua'
p=require("ScratchIO"):new {}

p:out('Hello world @ %s', os.date('%Y-%m %A %T'))

--]]
--

module(..., package.seeall)

--
-- The assumption here is that we will use a VoodooPad buffer named
-- '*sscratch*' for the output of the scripts we will be typing in a
-- buffer.
--

ScratchIO=require'PageIO':subclass {
   key = '*scratch*',
   nlines = 48,
   ncol = 80,
   attr = {
      background = 'yellow',
      font = { name = 'Monaco', size = 12 },
   },
   extant = nil,
}

function ScratchIO:init()
   if ScratchIO.extant then
      error('at most one instance')
   else
      ScratchIO.extant = self
   end

   self:seek(0)
   self:deleteToEOP()
   self:insert(((' '):rep(self.ncol) .. '\n'):rep(self.nlines), self.attr)
   self:seek(0)
end

function ScratchIO:out(fmt, ...)
   if fmt and type(fmt) == 'string' then
      self:replace(fmt:format(unpack(arg)) .. '\n', self.attr)
   else
      self:replace(('*** non string format %s'):format(tostring(fmt)))
   end

   self:display()
end

return ScratchIO