-- This file:
--   http://angg.twu.net/LUA/Lpeg4.lua.html
--   http://angg.twu.net/LUA/Lpeg4.lua
--           (find-angg "LUA/Lpeg4.lua")
-- Author: Eduardo Ochs <eduardoochs@gmail.com>
--
-- (defun e3 () (interactive) (find-angg "LUA/Lpeg3.lua"))
-- (defun e  () (interactive) (find-angg "LUA/Lpeg4.lua"))

lpeg = require("lpeg")

-- (find-es "lpeg" "pegdebug")
Path.prepend("path", "~/usrc/PegDebug/src/?.lua")
pegdebug = require("pegdebug")

-- (find-es "lpeg" "globals")
B,C,P,R,S,V = lpeg.B,lpeg.C,lpeg.P,lpeg.R,lpeg.S,lpeg.V
Cb,Cc,Cf,Cg = lpeg.Cb,lpeg.Cc,lpeg.Cf,lpeg.Cg
Cp,Cs,Ct    = lpeg.Cp,lpeg.Cs,lpeg.Ct
Carg,Cmt    = lpeg.Carg,lpeg.Cmt

-- (find-angg "LUA/LpegRex1.lua" "rectfromast")
rectfromast = function (o)
    if type(o) == "number" then return Rect.from(o) end
    if type(o) == "string" then return Rect.from(o) end
    if type(o) == "table" then
      local out = rectfromast(o[#o]):syn1()
      for i=#o-2,1,-2 do
        local lowerleft = rectfromast(o[i])
        local left = lowerleft:syn1(o[i+1])
        local left_ = left:pad0(1, left:width()+2, "_")
        out = left_ .. out
      end
      return out
    end
    PP("rectfromast can't handle this", o)
  end

-- Abstract Syntax Trees
Ast = Class {
  type = "Ast",
  from = function (...) return Ast({...}) end,
  fromsimp = function (...)
      local L = {...}                  -- if ... has a single argument
      if #L == 1 then return L[1] end  -- then return a simplified result.
      return Ast.from(...)
    end,
  __tostring = function (o) return rectfromast(o):tostring() end,
  __index = {
  },
}

-- (find-es "lpeg" "lpeg-quickref")
pskip  = P(" ")^0
pnum   = (R("09")^1):C() * pskip
plit   = function (str) return P(str)     * pskip end
ptok   = function (str) return P(str):C() * pskip end

palphanum = R("AZ","az")

Token = Class {
  type     = "Token",
  opstr1 = function (str)
      if str:match("^[A-Za-z]+$")
      then return (P(str)*-alphanum):C() * pskip
      else return P(str):C() * pskip
      end
    end,
  opfromlist = function (A, i, j)
      local op = Token.opstr1(A[i])
      for k=i+1,j do op = op + Token.opstr1(A[k]) end
      return op
    end,
  assocwith = function (bigstr)
      local A = split(bigstr)
      local v1 = V(A[1])
      local v2 = V(A[2]) * pskip
      local op = Token.opfromlist(A, 3, #A)
      return (v2 * (op * v2)^0) / Ast.fromsimp
    end,
  __index = {
  },
}


pexpr = P({
  "add",
   add    = Token.assocwith("add mul   + -"),
   mul    = Token.assocwith("mul norp  * /"),
   norp   = pnum + plit("(") * V("add") * plit(")"),
})

--[[
* (eepitch-lua51)
* (eepitch-kill)
* (eepitch-lua51)
dofile "Lpeg4.lua"
= pexpr:match( "1*2 + 3 + 4*5*6 + 7")
= pexpr:match("(1*2 + 3 + 4*5*6 + 7)")
= pexpr:match("(1*2 + 3 + 4*5*6 + 7) * 8")
PPP(pexpr:match( "1*2 + 3 + 4*5*6 + 7"))

--]]



-- Local Variables:
-- coding:  utf-8-unix
-- End: