-- This file:
--   http://anggtwu.net/LUA/DeleteComments3.lua.html
--   http://anggtwu.net/LUA/DeleteComments3.lua
--          (find-angg "LUA/DeleteComments3.lua")
-- Author: Eduardo Ochs <eduardoochs@gmail.com>
--
-- (defun e () (interactive) (find-angg "LUA/DeleteComments3.lua"))

-- Supersedes: (find-angg "LUA/DeleteComments1.lua")
--             (find-angg "LUA/DeleteComments2.lua")
--
-- Note that this does not convert double newlines into "\par"s!
-- See: (find-es "luatex" "3-questions-about-tex-print")
--      https://tug.org/pipermail/luatex/2024-September/008002.html


-- (find-angg "LUA/ELpeg1.lua" "globals")
lpeg              = lpeg or require "lpeg" 
local B,C,P,R,S,V = lpeg.B,lpeg.C,lpeg.P,lpeg.R,lpeg.S,lpeg.V
local Cb,Cc,Cf,Cg = lpeg.Cb,lpeg.Cc,lpeg.Cf,lpeg.Cg
local Cp,Cs,Ct    = lpeg.Cp,lpeg.Cs,lpeg.Ct
local Carg,Cmt    = lpeg.Carg,lpeg.Cmt

require "Gram4"   -- (find-angg "LUA/Gram4.lua")
local gr,V        = Gram4.new()

V.PR1         = P"%" * (1-S"\n")^0   -- a percent and everything at its right
V.NS1         = "\n" * (S" \t")^0    -- a newline and the spaces following it
V.PR2         = V.PR1 * V.NS2^-1     -- recurse starting from PR1
V.NS2         = V.NS1 * V.PR2^-1     -- recurse starting from NS1
V.comment     = V.PR2
V.commentspc  = V.comment / " "      -- comment, replaced by a single space
V.commentdel  = V.comment / ""       -- comment, deleted
V.bperc       = P"\\%"                                 -- backslack percent
V.bname       = P"\\"*R("AZ","az")^1                   -- backslash name
V.bnamespc    = P"\\"*R("AZ","az")^1 * V.commentspc^-1 -- backslash name space
V.unit        = V.bperc + V.bnamespc + V.commentdel + P(1)
V.delcomments = (V.unit^0):Cs()

deletecomments_pat = gr:compile("delcomments")
deletecomments     = function (bigstr)
    return deletecomments_pat:match(bigstr)
  end

--[[
* (eepitch-lua51)
* (eepitch-kill)
* (eepitch-lua51)
dofile "DeleteComments3.lua"
= deletecomments(      "%foo\n %plic\n  ploc")
= deletecomments("blergh%foo\n %plic\n  ploc")
= deletecomments("b\\rgh%foo\n %plic\n  ploc")

--]]





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