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John MacFarlane
ee2f0021f9
New module Text.Pandoc.Readers.Custom, exporting readCustom [API change]. Users can now do `-f myreader.lua` and pandoc will treat the script myreader.lua as a custom reader, which parses an input string to a pandoc AST, using the pandoc module defined for Lua filters. A sample custom reader can be found in data/reader.lua. Closes #7669.
45 lines
1.7 KiB
Lua
45 lines
1.7 KiB
Lua
-- A sample custom reader for a very simple markup language.
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-- This parses a document into paragraphs separated by blank lines.
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-- This is _{italic} and this is *{boldface}
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-- This is an escaped special character: \_, \*, \{, \}
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-- == text makes a level-2 heading
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-- That's it!
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-- For better performance we put these functions in local variables:
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local P, S, R, Cf, Cc, Ct, V, Cs, Cg, Cb, B =
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lpeg.P, lpeg.S, lpeg.R, lpeg.Cf, lpeg.Cc, lpeg.Ct, lpeg.V,
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lpeg.Cs, lpeg.Cg, lpeg.Cb, lpeg.B
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local whitespacechar = S(" \t\r\n")
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local specialchar = S("_*{}\\")
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local escapedchar = P"\\" * specialchar
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/ function (x) return string.sub(x,2) end
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local wordchar = (P(1) - (whitespacechar + specialchar)) + escapedchar
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local spacechar = S(" \t")
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local newline = P"\r"^-1 * P"\n"
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local blanklines = newline * spacechar^0 * newline^1
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local endline = newline - blanklines
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-- Grammar
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G = P{ "Pandoc",
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Pandoc = blanklines^-1 * Ct(V"Block"^0) / pandoc.Pandoc;
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Block = V"Header" + V"Para";
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Para = Ct(V"Inline"^1) * blanklines^-1 / pandoc.Para;
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Header = Ct(Cg(P("=")^1 / function(x) return #x end, "length")
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* spacechar^1
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* Cg(Ct(V"Inline"^0), "contents")
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* blanklines^-1) /
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function(res) return pandoc.Header(res.length, res.contents) end;
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Inline = V"Emph" + V"Str" + V"Space" + V"SoftBreak" + V"Special" ;
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Str = wordchar^1 / pandoc.Str;
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Space = spacechar^1 / pandoc.Space;
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SoftBreak = endline / pandoc.SoftBreak;
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Emph = Ct(P"_{" * Cg(Ct((V"Inline" - P"}")^1), "contents") * P"}") /
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function(res) return pandoc.Emph(res.contents) end;
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Special = specialchar / pandoc.Str;
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}
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function Reader(input)
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return lpeg.match(G, input)
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end
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