-- -- Copyright 2007-2023, Lua.org & PUC-Rio (see 'lpeg.html' for license) -- written by Roberto Ierusalimschy -- -- imported functions and modules local tonumber, type, print, error = tonumber, type, print, error local setmetatable = setmetatable local m = require"lpeg" -- 'm' will be used to parse expressions, and 'mm' will be used to -- create expressions; that is, 're' runs on 'm', creating patterns -- on 'mm' local mm = m -- patterns' metatable local mt = getmetatable(mm.P(0)) local version = _VERSION -- No more global accesses after this point _ENV = nil -- does no harm in Lua 5.1 local any = m.P(1) -- Pre-defined names local Predef = { nl = m.P"\n" } local mem local fmem local gmem local function updatelocale () mm.locale(Predef) Predef.a = Predef.alpha Predef.c = Predef.cntrl Predef.d = Predef.digit Predef.g = Predef.graph Predef.l = Predef.lower Predef.p = Predef.punct Predef.s = Predef.space Predef.u = Predef.upper Predef.w = Predef.alnum Predef.x = Predef.xdigit Predef.A = any - Predef.a Predef.C = any - Predef.c Predef.D = any - Predef.d Predef.G = any - Predef.g Predef.L = any - Predef.l Predef.P = any - Predef.p Predef.S = any - Predef.s Predef.U = any - Predef.u Predef.W = any - Predef.w Predef.X = any - Predef.x mem = {} -- restart memoization fmem = {} gmem = {} local mt = {__mode = "v"} setmetatable(mem, mt) setmetatable(fmem, mt) setmetatable(gmem, mt) end updatelocale() local I = m.P(function (s,i) print(i, s:sub(1, i-1)); return i end) local function patt_error (s, i) local msg = (#s < i + 20) and s:sub(i) or s:sub(i,i+20) .. "..." msg = ("pattern error near '%s'"):format(msg) error(msg, 2) end local function mult (p, n) local np = mm.P(true) while n >= 1 do if n%2 >= 1 then np = np * p end p = p * p n = n/2 end return np end local function equalcap (s, i, c) if type(c) ~= "string" then return nil end local e = #c + i if s:sub(i, e - 1) == c then return e else return nil end end local S = (Predef.space + "--" * (any - Predef.nl)^0)^0 local name = m.R("AZ", "az", "__") * m.R("AZ", "az", "__", "09")^0 local arrow = S * "<-" local seq_follow = m.P"/" + ")" + "}" + ":}" + "~}" + "|}" + (name * arrow) + -1 name = m.C(name) -- a defined name only have meaning in a given environment local Def = name * m.Carg(1) local function getdef (id, defs) local c = defs and defs[id] if not c then error("undefined name: " .. id) end return c end -- match a name and return a group of its corresponding definition -- and 'f' (to be folded in 'Suffix') local function defwithfunc (f) return m.Cg(Def / getdef * m.Cc(f)) end local num = m.C(m.R"09"^1) * S / tonumber local String = "'" * m.C((any - "'")^0) * "'" + '"' * m.C((any - '"')^0) * '"' local defined = "%" * Def / function (c,Defs) local cat = Defs and Defs[c] or Predef[c] if not cat then error ("name '" .. c .. "' undefined") end return cat end local Range = m.Cs(any * (m.P"-"/"") * (any - "]")) / mm.R local item = (defined + Range + m.C(any)) / m.P local Class = "[" * (m.C(m.P"^"^-1)) -- optional complement symbol * (item * ((item % mt.__add) - "]")^0) / function (c, p) return c == "^" and any - p or p end * "]" local function adddef (t, k, exp) if t[k] then error("'"..k.."' already defined as a rule") else t[k] = exp end return t end local function firstdef (n, r) return adddef({n}, n, r) end local function NT (n, b) if not b then error("rule '"..n.."' used outside a grammar") else return mm.V(n) end end local exp = m.P{ "Exp", Exp = S * ( m.V"Grammar" + m.V"Seq" * ("/" * S * m.V"Seq" % mt.__add)^0 ); Seq = (m.Cc(m.P"") * (m.V"Prefix" % mt.__mul)^0) * (#seq_follow + patt_error); Prefix = "&" * S * m.V"Prefix" / mt.__len + "!" * S * m.V"Prefix" / mt.__unm + m.V"Suffix"; Suffix = m.V"Primary" * S * ( ( m.P"+" * m.Cc(1, mt.__pow) + m.P"*" * m.Cc(0, mt.__pow) + m.P"?" * m.Cc(-1, mt.__pow) + "^" * ( m.Cg(num * m.Cc(mult)) + m.Cg(m.C(m.S"+-" * m.R"09"^1) * m.Cc(mt.__pow)) ) + "->" * S * ( m.Cg((String + num) * m.Cc(mt.__div)) + m.P"{}" * m.Cc(nil, m.Ct) + defwithfunc(mt.__div) ) + "=>" * S * defwithfunc(mm.Cmt) + ">>" * S * defwithfunc(mt.__mod) + "~>" * S * defwithfunc(mm.Cf) ) % function (a,b,f) return f(a,b) end * S )^0; Primary = "(" * m.V"Exp" * ")" + String / mm.P + Class + defined + "{:" * (name * ":" + m.Cc(nil)) * m.V"Exp" * ":}" / function (n, p) return mm.Cg(p, n) end + "=" * name / function (n) return mm.Cmt(mm.Cb(n), equalcap) end + m.P"{}" / mm.Cp + "{~" * m.V"Exp" * "~}" / mm.Cs + "{|" * m.V"Exp" * "|}" / mm.Ct + "{" * m.V"Exp" * "}" / mm.C + m.P"." * m.Cc(any) + (name * -arrow + "<" * name * ">") * m.Cb("G") / NT; Definition = name * arrow * m.V"Exp"; Grammar = m.Cg(m.Cc(true), "G") * ((m.V"Definition" / firstdef) * (m.V"Definition" % adddef)^0) / mm.P } local pattern = S * m.Cg(m.Cc(false), "G") * exp / mm.P * (-any + patt_error) local function compile (p, defs) if mm.type(p) == "pattern" then return p end -- already compiled local cp = pattern:match(p, 1, defs) if not cp then error("incorrect pattern", 3) end return cp end local function match (s, p, i) local cp = mem[p] if not cp then cp = compile(p) mem[p] = cp end return cp:match(s, i or 1) end local function find (s, p, i) local cp = fmem[p] if not cp then cp = compile(p) / 0 cp = mm.P{ mm.Cp() * cp * mm.Cp() + 1 * mm.V(1) } fmem[p] = cp end local i, e = cp:match(s, i or 1) if i then return i, e - 1 else return i end end local function gsub (s, p, rep) local g = gmem[p] or {} -- ensure gmem[p] is not collected while here gmem[p] = g local cp = g[rep] if not cp then cp = compile(p) cp = mm.Cs((cp / rep + 1)^0) g[rep] = cp end return cp:match(s) end -- exported names local re = { compile = compile, match = match, find = find, gsub = gsub, updatelocale = updatelocale, } if version == "Lua 5.1" then _G.re = re end return re