40 lines
886 B
Lua
40 lines
886 B
Lua
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local m = require'lpeglabel'
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local re = require'relabel'
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local terror = {}
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local function newError(s)
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table.insert(terror, s)
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return #terror
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end
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local errUndef = newError("undefined")
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local errId = newError("expecting an identifier")
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local errComma = newError("expecting ','")
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local id = m.R'az'^1
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local g = m.P{
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"S",
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S = m.V"Id" * m.V"List",
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List = -m.P(1) + m.V"Comma" * m.V"Id" * m.V"List",
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Id = m.V"Sp" * id + m.T(errId),
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Comma = m.V"Sp" * "," + m.T(errComma),
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Sp = m.S" \n\t"^0,
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}
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function mymatch (g, s)
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local r, e, sfail = g:match(s)
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if not r then
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local line, col = re.calcline(s, #s - #sfail)
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local msg = "Error at line " .. line .. " (col " .. col .. "): "
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return r, msg .. terror[e] .. " before '" .. sfail .. "'"
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end
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return r
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end
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print(mymatch(g, "one,two"))
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print(mymatch(g, "one two"))
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print(mymatch(g, "one,\n two,\nthree,"))
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