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local m = require'lpeglabel'
local re = require'relabel'
local terror = {
ErrId = "expecting an identifier",
ErrComma = "expecting ','"
}
local subject, errors
local function recorderror(pos, lab)
local line, col = re.calcline(subject, pos)
table.insert(errors, { line = line, col = col, msg = terror[lab] })
end
local function record (lab)
return (m.Cp() * m.Cc(lab)) / recorderror
end
local function sync (p)
return (-p * m.P(1))^0
end
local id = m.R'az'^1
local g = m.P{
"S",
S = m.V"Id" * m.V"List",
List = -m.P(1) + m.V"Comma" * m.V"Id" * m.V"List",
Id = m.V"Sp" * id + m.T'ErrId',
Comma = m.V"Sp" * "," + m.T'ErrComma',
Sp = m.S" \n\t"^0,
ErrId = record('ErrId') * sync(m.P","),
ErrComma = record('ErrComma') * sync(id),
}
function mymatch (g, s)
errors = {}
subject = s
local r, e, sfail = g:match(s)
if #errors > 0 then
local out = {}
for i, err in ipairs(errors) do
local msg = "Error at line " .. err.line .. " (col " .. err.col .. "): " .. err.msg
table.insert(out, msg)
end
return nil, table.concat(out, "\n") .. "\n"
end
return r
end
print(mymatch(g, "one,two"))
print(mymatch(g, "one two three"))
print(mymatch(g, "1,\n two, \n3,"))
print(mymatch(g, "one\n two123, \nthree,"))
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