typo.lua

--https://pandoc.org/lua-filters.html

-- Links ----------------------------------------------------------------------
function Link(el)
  if FORMAT:match"html" then
    el.target = el.target:gsub("%.md$",".html")
  end
  return el
end

-- Kbd ------------------------------------------------------------------------
local kbd = '<span class="nowrap">%s</span>'
function Subscript(el)
  if FORMAT:match"html" then
    if #el.c==1 then
      return pandoc.RawInline("html",kbd:format(el.c[1].text:gsub("[^+]+","<kbd>%0</kbd>")))
    end
  else
    --return pandoc...
  end
  return el
end

-- Typographics ---------------------------------------------------------------
local typo = {
  ["=>"]="⟹",
  ["->"]="⟶",
  [">="]="≥",
  ["<="]="≤",
  ["~="]="≠",
  ["=="]="≡",
  ["%.%.%."]="…",
  ["-,"]="—,",
  ["-/"]="—/",
}

function Str(el)
  local text = el.text
  for k,v in pairs(typo) do
    text = text:gsub(k,typo)
  end
  if text=="-" then text = "—" end
  el.text = text
  return el
end

--⇒
--➡
--≤
--≥
--≠
--→
--"⟶"	U27F6 # LONG RIGHTWARDS ARROW
--"⟹"	U27F9 # LONG RIGHTWARDS DOUBLE ARROW


-- code blocks with numbered lines --------------------------------------------
local N = 4
function CodeBlock(el)
  if #el.classes==1 and select(2,el.text:gsub("\n","\n"))>=N then
    table.insert(el.classes,"numberLines")
  end
  return el
end

-- pagetitle from header ------------------------------------------------------
local title
function Header(el) 
  if not title and el.level==1 then
    title = pandoc.utils.stringify(el)
  end
end 

function Meta(meta)
  meta.pagetitle = title
  return meta
end