-- This file:
--   http://anggtwu.net/LUA/DeleteComments1.lua.html
--   http://anggtwu.net/LUA/DeleteComments1.lua
--          (find-angg "LUA/DeleteComments1.lua")
-- Author: Eduardo Ochs <eduardoochs@gmail.com>
--
-- (defun e () (interactive) (find-angg "LUA/DeleteComments1.lua"))
-- Based on: (find-dn6 "output.lua" "Deletecomments-class")

-- «.DeleteComments»	(to "DeleteComments")




--  ____       _      _        ____                                     _       
-- |  _ \  ___| | ___| |_ ___ / ___|___  _ __ ___  _ __ ___   ___ _ __ | |_ ___ 
-- | | | |/ _ \ |/ _ \ __/ _ \ |   / _ \| '_ ` _ \| '_ ` _ \ / _ \ '_ \| __/ __|
-- | |_| |  __/ |  __/ ||  __/ |__| (_) | | | | | | | | | | |  __/ | | | |_\__ \
-- |____/ \___|_|\___|\__\___|\____\___/|_| |_| |_|_| |_| |_|\___|_| |_|\__|___/
--                                                                              
-- «DeleteComments»  (to ".DeleteComments")
-- This class implements a way to delete comments that TRIES to
-- simulate what TeX does. The TeXBook explains in its pages 46-47
-- that the "eyes" and "mouth" of TeX enter the "State S" (for
-- "skipping blanks") after a "%"; we simulate that by splitting
-- bigstr in a certain way, and then after each "%" we delete the
-- "%..." part of that line plus the whitespaces and newlines in
-- (hopefully) the right places.
--
-- This version doesn't treat backslashes followed by "%"s in the
-- right way. This is still to be done.
--
-- See: (find-es "tex" "comments")
--      (find-es "tex" "comments" "Skipping blanks")
--
DeleteComments = Class {
  type  = "DeleteComments",
  split = function (bigstr)
      local A = {}
      for _,li in ipairs(splitlines(bigstr)) do
        local a,b = li:match("^([^%%]*)(.*)")
        table.insert(A, {a, b, "\n"})
      end
      return DeleteComments(A)
    end,
  from = function (bigstr)
      return DeleteComments.split(bigstr):delcomments():concat()
    end,
  __tostring = function (dc) return mytabletostring(dc) end,
  __index = {
      hascomment = function (dc, k) return dc[k][2] ~= "" end,
      endswithcmd = function (dc, k)
          return dc[k][1]:reverse():match("^[A-Za-z]+\\")
        end,
      addspaceaftercmd = function (dc, k)
          dc[k][1] = dc[k][1].." "
        end,
      valid = function (dc, k) return 1 <= k and k <= #dc end,
      ltrim = function (dc, k)
          dc[k][1] = dc[k][1]:match("^[ \t]*(.*)")
        end,
      delcomment = function (dc, k)
          if dc:endswithcmd(k) then dc:addspaceaftercmd(k) end
          dc[k][2] = ""		-- delete the "%..."
          dc[k][3] = ""		-- delete the newline
          if dc:valid(k+1) then dc:ltrim(k+1) end
        end,
      delcomments = function (dc)
          for k=1,#dc do if dc:hascomment(k) then dc:delcomment(k) end end
	  return dc
        end,
      concat = function (dc)
          local bigstr = ""
          for k=1,#dc-1 do bigstr = bigstr..dc[k][1]..dc[k][2]..dc[k][3] end
          if #dc > 0 then bigstr = bigstr..dc[#dc][1]..dc[#dc][2] end
          return bigstr
        end,
  },
}

-- «DeleteComments-tests»  (to ".DeleteComments-tests")
-- (find-es "dednat" "deletecomments-2021")
--[==[
* (eepitch-lua51)
* (eepitch-kill)
* (eepitch-lua51)
dofile "DeleteComments1.lua"

bigstr = [[
foo%12
  bar\plic%34
  qoo%56
  blep
  bletch
  %
  woo
]]

dc = DeleteComments.split(bigstr)
= dc
= dc:delcomments()
= dc:concat()

--]==]





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