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"
}

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

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 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"))
-- print(lpegmatch(scripted,"10^-a"))