if not modules then modules = { } end modules ['cldf-bas'] = {
    version   = 1.001,
    comment   = "companion to cldf-ini.mkiv",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

-- used in chem-ini.lua

local lpegmatch, patterns = lpeg.match, lpeg.patterns
local P, R, V, Cc, Cs = lpeg.P, lpeg.R, lpeg.V, lpeg.Cc, lpeg.Cs
local format = string.format

local cpatterns    = patterns.context or { }
patterns.context   = cpatterns

local backslash    = P("\\")
local csname       = backslash * P(1) * (1-backslash)^0
local sign         = P("+") / "\\textplus "
                   + P("-") / "\\textminus "
local leftbrace    = P("{")
local rightbrace   = P("}")
local nested       = P { leftbrace * (V(1) + (1-rightbrace))^0 * rightbrace }
local subscript    = P("_")
local superscript  = P("^")
local utf8char     = patterns.utf8char
local cardinal     = patterns.cardinal

-- local scripts   = P { "start",
--                       start     = V("csname") + V("lowfirst") + V("highfirst"),
--                       csname    = csname,
--                       content   = Cs(V("csname") + nested + sign^-1 * (cardinal + utf8char)),
--                       lowfirst  = subscript   * ( Cc("\\lohi{%s}{%s}") * V("content") * superscript + Cc("\\low{%s}" ) ) * V("content") / format,
--                       highfirst = superscript * ( Cc("\\hilo{%s}{%s}") * V("content") * subscript   + Cc("\\high{%s}") ) * V("content") / format,
--                   }

local scripts      = P { "start",
                         start     = V("csname") + V("lowfirst") + V("highfirst"),
                         csname    = csname,
                         content   = Cs(V("csname") + nested + sign^-1 * (cardinal + utf8char)),
                         lowfirst  = (subscript  /"") * ( Cc("\\lohi{") * V("content") * Cc("}{") * (superscript/"") + Cc("\\low{" ) ) * V("content") * Cc("}"),
                         highfirst = (superscript/"") * ( Cc("\\hilo{") * V("content") * Cc("}{") * (subscript  /"") + Cc("\\high{") ) * V("content") * Cc("}"),
                     }

local scripted     = Cs((csname + scripts + utf8char)^0)

cpatterns.scripts  = scripts
cpatterns.csname   = csname
cpatterns.scripted = scripted
cpatterns.nested   = nested

-- inspect(scripted)
-- print(lpegmatch(scripted,"10^-3_x"))
-- print(lpegmatch(scripted,"10^-a"))