-- This file:
--   http://angg.twu.net/LUA/Arith2.lua.html
--   http://angg.twu.net/LUA/Arith2.lua
--           (find-angg "LUA/Arith2.lua")
-- Author: Eduardo Ochs <eduardoochs@gmail.com>
--
-- (defun a () (interactive) (find-angg "LUA/Arith2.lua"))
-- (defun o () (interactive) (find-angg "LUA/Arith1.lua"))
--
-- «.top-down-parser»	(to "top-down-parser")


Tokens = Class {
  fromcs = function (str) return Tokens(split(str, "(.)")) end,
  fromws = function (str) return Tokens(split(str)) end,
  type    = "Tokens",
  __tostring = function (tks) return tks:tostring() end,
  __index = {
    torect1 = function (tks, i)
        return Rect.from(tks[i].."\n"..i)
      end,
    torect = function (tks, i, j)
        i, j = i or 1, j or #tks
        local out = tks:torect1(i)
        for k=i+1,j do out = out.." "..tks:torect1(k) end
        return out
      end,
    torectp = function (tks) return tks:torect() .. "  pos=" .. tks.pos end,
    tostring1 = function (tks, i, j, sep)
        return table.concat(tks, sep or tks.sep or "", i or 1, j or #tks)
      end,
    tostring = function (tks, i, j)
        return tks:torect(i or 1, j or #tks):tostring()
      end,
    tostringp = function (tks) return tks:torectp():tostring() end,
    sub = function (tks, i, j) return TokenSeq.from(tks, i, j) end,
  },
}

TokenSeq = Class {
  type = "TokenSeq",
  from = function (tks, i, j) return TokenSeq {tks=tks, i=i, j=j} end,
  __tostring = function (ts) return ts:tostring1() end,
  __concat   = function (tsl, tsr) return tsl:glue(tsr) end,
  __index = {
    tostring1 = function (ts) return ts.tks:tostring1(ts.i, ts.j) end,
    tostring  = function (ts) return ts.tks:tostring (ts.i, ts.j) end,
    glue = function (tsl, tsr) return TokenSeq.from(tsl.tks, tsl.i, tsr.j) end,
  },
}

-- (find-dn6 "stacks.lua" "Stack")
--
Stack = Class {
  type    = "Stack",
  new     = function () return Stack {} end,
  --
  __tostring = function (s) return mapconcat(tostring, s, " ") end,
  __index = {
    push  = function (s, o) table.insert(s, o); return s end,
    pushs = function (s, ...) for _,o in ipairs({...}) do s:push(o) end; return s end,
    --
    check     = function (s) assert(#s>0, s.msg or "Empty stack"); return s end,
    drop      = function (s) s:check(); s[#s]=nil; return s end,
    dropn     = function (s, n) for i=1,n  do s:drop() end; return s end,
    dropuntil = function (s, n) while #s>n do s:drop() end; return s end,
    clear     = function (s)    return s:dropn(#s) end,
    --
    pop  = function (s) return                            s[#s], s:dropn(1) end,
    pop2 = function (s) return                   s[#s-1], s[#s], s:dropn(2) end,
    pop3 = function (s) return          s[#s-2], s[#s-1], s[#s], s:dropn(3) end,
    pop4 = function (s) return s[#s-3], s[#s-2], s[#s-1], s[#s], s:dropn(4) end,
    --
    pick = function (s, offset) return s[#s-offset] end,
    pock = function (s, offset, o)     s[#s-offset] = o; return s end,
  },
}

--[[
* (eepitch-lua51)
* (eepitch-kill)
* (eepitch-lua51)
dofile "Arith2.lua"
tks = Tokens.fromcs "(1+2)*3^(4+5)"
tks.pos = 1
= tks
= tks:sub(3,5)
= tks:sub(3,5):tostring1()
= tks:sub(3,5):tostring()
s = Stack.new()
s:pushs(22, 44)
= s
s = Stack.new()
s:pushs(tks:sub(3,6), tks:sub(7,9))
= s

--]]




Vocab = Class {
  type = "Vocab",
  fmt  = "%12s %s",
  new  = function () return Vocab {_ = SetL.new()} end,
  __tostring = function (v) return v:tostring() end,
  __index = {
    add1 = function (v, key, src)
        v._:add(key, Code.vc(" o => " .. src))
      end,
  },
}


--[[
* (eepitch-lua51)
* (eepitch-kill)
* (eepitch-lua51)
dofile "Arith2.lua"

v = Vocab.new()
v:add1("foo", "bar")
v:add1("plic", "ploc")
v:add1("a", "b")

= v._:ksc()
= v._:get("foo")
= v._:get("foo").src
= v._:get("foo").code



--]]



-- «top-down-parser»  (to ".top-down-parser")

parse_n = function (pos)
    if tks[pos]:match("[0-9]") then
      return "ok", pos+1, sub(pos, pos)
    end
  end

parse_plus = function (pos)
    if tks[pos] == "+" then
      return "ok", pos+1, sub(pos, pos)
    end
  end

parse_openp = function (pos)
    if tks[pos] == "(" then
      return "ok", pos+1, sub(pos, pos)
    end
  end

parse_closep = function (pos)
    if tks[pos] == ")" then
      return "ok", pos+1, sub(pos, pos)
    end
  end

--

parse_plusnorp = function (pos)
    local ok1,pos1,o1 = parse_plus(pos)
    if not ok1 then return end
    local ok2,pos2,o2 = parse_norp(pos1)
    if not ok2 then return end
    return ok2, pos2, sub(pos,pos2-1)
  end

parse_plusnorps = function (pos)
    local pos1 = pos
    while true do
      local ok2,pos2,o2 = parse_plusnorp(pos1)
      if ok2 then
        pos1 = pos2
      else
        return "ok",pos1,sub(pos,pos1-1)
      end
    end
  end

parse_norps = function (pos)
    local ok1,pos1,o1 = parse_norp(pos)
    if not ok1 then return end
    local ok2,pos2,o2 = parse_plusnorps(pos1)
    return ok2, pos2, sub(pos,pos2-1)
  end

parse_norp = function (pos)
    local ok1,pos1,o1 = parse_n(pos)
    if ok1 then return ok1,pos1,o1 end
    local ok1,pos1,o1 = parse_p(pos)
    if ok1 then return ok1,pos1,o1 end
  end

parse_p = function (pos)
    local ok1,pos1,o1 = parse_openp(pos)
    if not ok1 then return end
    local ok2,pos2,o2 = parse_norps(pos1)
    if not ok2 then return end
    local ok3,pos3,o3 = parse_closep(pos2)
    if ok3 then return "ok", pos3, sub(pos, pos3-1) end
  end




--[[
* (eepitch-lua51)
* (eepitch-kill)
* (eepitch-lua51)
dofile "Arith2.lua"

= id(2,3,4)
= 1 and id(2,3,4)

tks = Tokens.fromcs "(1+2+3)+4+(5+6)"
tks.pos = 1
= tks
sub = function (i, j) return tks:sub(i, j) end
= parse_openp(1)
= parse_n(2)
= parse_plus(3)
= parse_n(4)
= parse_closep(5)
= parse_p(1)    -- =(
= parse_plusnorp(3)
= parse_plusnorps(3)
= parse_norp(2)
= parse_norp(4)
= parse_norps(2)
= parse_norp(1)
= parse_norps(1)

--]]







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