Replace old sample custom reader with a full-featured reader for creole.
This is better as an example. And it is faster than pandoc's regular creole parser, which shows that high-performance readers can be developed this way.
This commit is contained in:
John MacFarlane
parent
213913f025
commit
881b45209e
4 changed files with 200 additions and 88 deletions
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@ -6594,7 +6594,7 @@ of the functions that are available for creating pandoc
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AST elements. For parsing, the [lpeg] parsing library
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is available by default. To see a sample custom reader:
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pandoc --print-default-data-file reader.lua
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pandoc --print-default-data-file creole.lua
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If you want your custom reader to have access to reader options
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(e.g. the tab stop setting), you give your Reader function a
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197
data/creole.lua
Normal file
197
data/creole.lua
Normal file
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@ -0,0 +1,197 @@
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-- A sample custom reader for Creole 1.0 (common wiki markup)
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-- http://www.wikicreole.org/wiki/CheatSheet
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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, C, Cmt =
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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, lpeg.C, lpeg.Cmt
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local whitespacechar = S(" \t\r\n")
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local specialchar = S("/*~[]\\{}|")
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local wordchar = (1 - (whitespacechar + specialchar))
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local spacechar = S(" \t")
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local newline = P"\r"^-1 * P"\n"
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local blankline = spacechar^0 * newline
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local endline = newline * #-blankline
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local endequals = spacechar^0 * P"="^0 * spacechar^0 * newline
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local cellsep = spacechar^0 * P"|"
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local function trim(s)
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return (s:gsub("^%s*(.-)%s*$", "%1"))
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end
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local function ListItem(lev, ch)
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local start
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if ch == nil then
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start = S"*#"
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else
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start = P(ch)
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end
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local subitem = function(c)
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if lev < 6 then
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return ListItem(lev + 1, c)
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else
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return (1 - 1) -- fails
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end
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end
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local parser = spacechar^0
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* start^lev
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* #(- start)
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* spacechar^0
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* Ct((V"Inline" - (newline * spacechar^0 * S"*#"))^0)
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* newline
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* (Ct(subitem("*")^1) / pandoc.BulletList
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+
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Ct(subitem("#")^1) / pandoc.OrderedList
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+
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Cc(nil))
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/ function (ils, sublist)
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return { pandoc.Plain(ils), sublist }
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end
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return parser
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end
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local re = require're'
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x = re.compile[[
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listname <- {| {:tag: '' -> 'list':} (name s)* |}
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name <- {| {:tag: '' -> 'id':} {[a-z][a-z]*} |}
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s <- ' '*
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]]
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-- Grammar
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G = P{ "Doc",
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Doc = Ct(V"Block"^0)
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/ pandoc.Pandoc ;
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Block = blankline^0
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* ( V"Header"
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+ V"HorizontalRule"
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+ V"CodeBlock"
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+ V"List"
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+ V"Table"
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+ V"Para") ;
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Para = Ct(V"Inline"^1)
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* newline
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/ pandoc.Para ;
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HorizontalRule = spacechar^0
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* P"----"
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* spacechar^0
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* newline
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/ pandoc.HorizontalRule;
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Header = (P("=")^1 / string.len)
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* spacechar^1
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* Ct((V"Inline" - endequals)^1)
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* endequals
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/ pandoc.Header;
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CodeBlock = P"{{{"
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* blankline
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* C((1 - (newline * P"}}}"))^0)
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* newline
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* P"}}}"
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/ pandoc.CodeBlock;
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Placeholder = P"<<<"
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* C(P(1) - P">>>")^0
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* P">>>"
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/ function() return pandoc.Div({}) end;
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List = V"BulletList"
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+ V"OrderedList" ;
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BulletList = Ct(ListItem(1,'*')^1)
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/ pandoc.BulletList ;
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OrderedList = Ct(ListItem(1,'#')^1)
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/ pandoc.OrderedList ;
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Table = (V"TableHeader" + Cc{})
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* Ct(V"TableRow"^1)
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/ function(headrow, bodyrows)
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local numcolumns = #(bodyrows[1])
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local aligns = {}
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local widths = {}
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for i = 1,numcolumns do
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aligns[i] = pandoc.AlignDefault
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widths[i] = 0
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end
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return pandoc.utils.from_simple_table(
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pandoc.SimpleTable({}, aligns, widths, headrow, bodyrows))
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end ;
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TableHeader = Ct(V"HeaderCell"^1)
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* cellsep^-1
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* spacechar^0
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* newline ;
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TableRow = Ct(V"BodyCell"^1)
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* cellsep^-1
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* spacechar^0
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* newline ;
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HeaderCell = cellsep
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* P"="
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* spacechar^0
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* Ct((V"Inline" - (newline + cellsep))^0)
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/ function(ils) return { pandoc.Plain(ils) } end ;
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BodyCell = cellsep
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* spacechar^0
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* Ct((V"Inline" - (newline + cellsep))^0)
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/ function(ils) return { pandoc.Plain(ils) } end ;
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Inline = V"Emph"
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+ V"Strong"
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+ V"LineBreak"
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+ V"Link"
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+ V"URL"
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+ V"Image"
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+ V"Str"
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+ V"Space"
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+ V"SoftBreak"
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+ V"Escaped"
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+ V"Placeholder"
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+ V"Code"
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+ V"Special" ;
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Str = wordchar^1
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/ pandoc.Str;
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Escaped = P"~"
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* C(P(1))
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/ pandoc.Str ;
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Special = specialchar
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/ pandoc.Str;
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Space = spacechar^1
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/ pandoc.Space ;
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SoftBreak = endline
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* # -(V"HorizontalRule" + V"CodeBlock")
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/ pandoc.SoftBreak ;
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LineBreak = P"\\\\"
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/ pandoc.LineBreak ;
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Code = P"{{{"
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* C((1 - P"}}}")^0)
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* P"}}}"
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/ trim / pandoc.Code ;
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Link = P"[["
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* C((1 - (P"]]" + P"|"))^0)
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* (P"|" * Ct((V"Inline" - P"]]")^1))^-1 * P"]]"
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/ function(url, desc)
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local txt = desc or {pandoc.Str(url)}
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return pandoc.Link(txt, url)
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end ;
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Image = P"{{"
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* #-P"{"
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* C((1 - (S"}"))^0)
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* (P"|" * Ct((V"Inline" - P"}}")^1))^-1
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* P"}}"
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/ function(url, desc)
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local txt = desc or ""
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return pandoc.Image(txt, url)
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end ;
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URL = P"http"
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* P"s"^-1
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* P":"
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* (1 - (whitespacechar + (S",.?!:;\"'" * #whitespacechar)))^1
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/ function(url)
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return pandoc.Link(pandoc.Str(url), url)
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end ;
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Emph = P"//"
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* Ct((V"Inline" - P"//")^1)
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* P"//"
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/ pandoc.Emph ;
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Strong = P"**"
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* Ct((V"Inline" -P"**")^1)
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* P"**"
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/ pandoc.Strong ;
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}
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function Reader(input, reader_options)
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return lpeg.match(G, input)
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end
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@ -1,87 +0,0 @@
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-- 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* and this is `code`
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-- and `code``with backtick` (doubled `` = ` inside backticks).
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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, C, Cmt =
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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, lpeg.C, lpeg.Cmt
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--- if item is a table, concatenate it to acc;
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-- otherwise insert it at the end.
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local function add_item(acc, item)
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if acc == nil then
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acc = {}
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end
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if type(item) == "table" then
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for i = 1,#item do
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add_item(acc, item[i])
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end
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else
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acc[#acc + 1] = item
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end
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return acc
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end
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local function Many1(parser)
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return Cf(Cc(nil) * parser^1 , add_item)
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end
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local function Many(parser)
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return (Many1(parser) + Cc{})
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end
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local whitespacechar = S(" \t\r\n")
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local specialchar = S("/*\\`")
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local wordchar = (1 - (whitespacechar + specialchar))
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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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local function BetweenDelims(c, parser, constructor)
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local starter = P(c) * #(- whitespacechar)
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local ender = B(1 - whitespacechar) * P(c)
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return starter * Many(parser - ender) * C(ender^-1) /
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function(contents, ender)
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if ender == "" then -- fallback
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return { pandoc.Str(c) , contents }
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else
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return constructor(contents)
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end
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end
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end
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-- Grammar
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G = P{ "Pandoc",
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Pandoc = Many(V"Block") / pandoc.Pandoc;
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Block = blanklines^0 * (V"Header" + V"Para") ;
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Para = Many1(V"Inline") * blanklines^-1 / pandoc.Para;
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Header = (P("=")^1 / string.len)
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* spacechar^1
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* Many(V"Inline" - (spacechar^0 * P("=")^0 * blanklines))
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* spacechar^0
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* P("=")^0
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* blanklines^-1 /
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function(lev, contents) return pandoc.Header(lev, contents) end;
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Inline = V"Emph" + V"Strong" + V"Str" + V"Space" + V"SoftBreak" +
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V"Code" + V"Escaped" + V"Special";
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Str = wordchar^1 / pandoc.Str;
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Escaped = "\\" * C(specialchar) / function(s) return pandoc.Str(s) end;
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Space = spacechar^1 / pandoc.Space;
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SoftBreak = endline / pandoc.SoftBreak;
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Emph = BetweenDelims("/", V"Inline", pandoc.Emph);
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Strong = BetweenDelims("*", V"Inline", pandoc.Strong);
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Code = P"`" * Ct(( (P"``" / "`") + (C(1) - S"`"))^1) * P"`"
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/ table.concat / pandoc.Code;
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Special = S"`\\" / pandoc.Str;
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}
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function Reader(input, opts)
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return lpeg.match(G, input)
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end
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@ -174,6 +174,8 @@ data-files:
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data/abbreviations
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-- sample lua custom writer
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data/sample.lua
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-- sample lua custom reader
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data/creole.lua
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-- lua init script
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data/init.lua
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-- pandoc lua module
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