if not modules then modules = { } end modules ['t-readdata'] = {
    version   = "0.13",
    comment   = "Readdata",
    author    = "Tomáš Hála",
    copyright = "Tomáš Hála, 2020",
    email     = "thala@mendelu.cz",
    license   = "GNU General Public License"
}

------------------------------
ctx = context
------------------------------

local err = function (kod) 
  local msg={ECOL="Error in column name",
  	     INCN="Incorrect area (column numbers)",
   	     MDSN="Missing dataset name",
   	     MFNM="Missing file name",
             MKEY="Missing key data",
             NDTS="No dataset of this name",
             RCND="No row or column defined",}
  ctx("\\errmessage{"..msg[kod]..".}")
  inspect("\\errmessage{"..msg[kod]..".}")
end 

------------------------------

thirddata            = thirddata or {}
thirddata.readdata   = thirddata.readdata or {}
local d              = thirddata.readdata

d.methods,d.sepdefault={},","

------------------------------

function d.readdata (keyvals)  
  local kv = utilities.parsers.settings_to_hash(keyvals)
  local nocurves = not kv.curve and not kv.curves 
  d.method = (kv.method or "plain"):strip()  
  local data = kv.data or d.method:strip()=="dataset" or d.method:strip()=="installdataset" 
  if not data and nocurves then err("MKEY") end
 --
  local list = {"c","r","cx","cy","rx","ry" }
  for i=1,#list do d[list[i]]=nil if kv[list[i]] then
  d[list[i]]=kv[list[i]]:strip() end end
  d.data,d.curves,d.dataset={},{},d.dataset or {}
  d.decimal = kv.decimal or "dot"
  d.sep = kv.sep or d.sepdefault
  d.xlabels=(kv.xlabels or ""):split(d.sep)
  d.ylabels=(kv.ylabels or ""):split(d.sep)
  if kv.curves then d.curves=(kv.curves:strip()):split(",") end
  for i=1,#d.curves do d.curves[i]=d.curves[i]:sub(2,-2) end
  if kv.curve then table.insert(d.curves,1,kv.curve) end 
  if data then d.methods[d.method](kv) end
--inspect(":::")  inspect(d) os.exit()
  return d
end

local function string2array (r,sep,decimal)
  local x = r:split(sep)
  local d={}
  for i=1,#x do 
    d[i]=x[i]:strip()
    local ok=d[i]:find("^[+-]*%d+,%d+e?%d+$")
    if decimal=="comma" and ok==1 
      then local x=d[i]:gsub(',','.') d[i]=tonumber(x) 
      else d[i]=tonumber(d[i]) or d[i]
    end 
  end
  return d
end

local function readfile(fn,sep,decimal) 
  local f,d,i = io.input(fn),{},0
  for line in f:lines() do
    i=i+1
    d[i]=string2array(line,sep,decimal)
  end 
  f:close()
  return d
end

local function columntonumber(r,pos)
  pos=pos or r:len()
  c=tonumber(r:sub(pos+1)) or nil
  r=('@'..r):sub(pos,pos+1)
  -- max 2 letters
  r=tonumber((r:byte(1)-64)*26+(r:byte(2)-64))
  return r,c
end

local function maxdata(i,ds)  
  if i then return #ds[1] else return #ds end
end

------------------------------

d.methods.plain = function (kv) 
  d.data[1]=string2array(kv.data,d.sep,d.decimal)
--inspect(">>>") inspect(d) os.exit()
end

d.methods.joined = function (kv) 
  local x = kv.data:split(d.sep)
--  local d = documentdata.statcharts
  j,k=0,0
  for i=1,#x do 
    k = k + 1 
    if k == 1 then j=j+1 d.data[j]={} end
    d.data[j][k]=tonumber(x[i]:strip()) 
    if k == tonumber(kv.per) then k=0 end
  end
--  return d
end

d.methods.struct = function (kv)
--  local dd = documentdata.statcharts
  local transpose = (kv.r or ""):strip() =="c" or (kv.c or ""):strip()=="r"
  local kd = kv.data:strip() 
  kd = kd:sub(2,-2) 
  local x = kd:split("}"..d.sep.."{")
  for i=1,#x do 
    d.data[i]=x[i]:split(d.sep)
    for j=1,#d.data[i] do d.data[i][j]=tonumber(d.data[i][j]:strip()) end
  end
  if transpose then 
    local xx=d.data d.data={}
    for i=1,#xx[1] do d.data[i]={}
      for j=1,#xx do d.data[i][j]=xx[j][i] end
    end
  end
end

d.methods.installdataset = function (kv)  
  if lfs.isfile(kv.filename) 
    then d.dataset[kv.dsname]=readfile(kv.filename,d.sep,d.decimal) 
    else err("MFNM")
  end
end


d.methods.dataset = function (kv)  
  if not kv.dsname or kv.dsname:strip() == "" then err("MDSN") end
  if not kv.rx and not kv.cx then err("RCND") end
  if kv.filename and lfs.isfile(kv.filename) 
    then d.dataset[kv.dsname]=readfile(kv.filename,d.sep,d.decimal) 
    else if not d.dataset[kv.dsname] then err("NDTS") end
  end

  local axis={}
  axis[1],axis[2]=((d.rx or d.cx):strip()):split(":"),(((d.ry or d.cy) or ""):strip()):split(":")
  local xx,yy=axis[1],axis[2]

  for a=1,#axis do local ax=axis[a]
  for i=1,#ax do 
    local bn=string.find(ax[i],"%d+$") or 0
    local bl=ax[i]:find("^[A-Z]+") or 0
    if       bn ==1          then ax[i]={tonumber(ax[i])}
      elseif bl ==1 and bn<1 then ax[i]={columntonumber(ax[i])}
      elseif bl ==1 and bn>1 then ax[i]={columntonumber(ax[i],bn-1)}
      else   err("ECOL")
    end
  end 
  end

  d.data={{},{}}
  for a=1,#axis do
    local ax=axis[a] 
    ax[2]=ax[2] or {}
    ax[2][1]=ax[2][1] or ax[1][1] 
    ax[1][2]=ax[1][2] or 1
    ax[2][2]=ax[2][2] or maxdata(kv.rx,d.dataset[kv.dsname])
    if ax[1][1]~=ax[2][1] then err("INCN") end

    for i=ax[1][2],ax[2][2] do 
      local xx,yy,kam=ax[1][1],i,i-ax[1][2]+1
      if not kv.rx then xx,yy=i,ax[1][1] end
      d.data[a][kam]=d.dataset[kv.dsname][xx][yy]
    end
  end

end

return d
------------------------------