From 5ada504d5667a6f17ee2631dd471b073b332dd33 Mon Sep 17 00:00:00 2001
From: Melody Horn <melody@boringcactus.com>
Date: Mon, 26 Oct 2020 23:22:29 -0600
Subject: build spec in gemtext too

---
 etc/gemtext.lua | 297 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 297 insertions(+)
 create mode 100644 etc/gemtext.lua

(limited to 'etc/gemtext.lua')

diff --git a/etc/gemtext.lua b/etc/gemtext.lua
new file mode 100644
index 0000000..5fdff59
--- /dev/null
+++ b/etc/gemtext.lua
@@ -0,0 +1,297 @@
+-- Invoke with: pandoc -t gemtext.lua
+
+-- Tables to store links and footnotes, so they can be included correctly.
+local links = {}
+local notes = {}
+
+-- Blocksep is used to separate block elements.
+function Blocksep()
+    return "\n"
+end
+
+-- This function is called once for the whole document. Parameters:
+-- body is a string, metadata is a table, variables is a table.
+-- This gives you a fragment.  You could use the metadata table to
+-- fill variables in a custom lua template.  Or, pass `--template=...`
+-- to pandoc, and pandoc will do the template processing as usual.
+function Doc(body, metadata, variables)
+    local buffer = {}
+    local function add(s)
+        table.insert(buffer, s)
+    end
+    add(body)
+    if #notes > 0 then
+        add('')
+        for _,note in pairs(notes) do
+            add(note)
+        end
+    end
+    return table.concat(buffer, '\n')
+end
+
+-- The functions that follow render corresponding pandoc elements.
+-- s is always a string, attr is always a table of attributes, and
+-- items is always an array of strings (the items in a list).
+-- Comments indicate the types of other variables.
+
+function Str(s)
+    return s
+end
+
+function Space()
+    return " "
+end
+
+function SoftBreak()
+    return " "
+end
+
+function LineBreak()
+    return "\n"
+end
+
+function Emph(s)
+    return "_" .. s .. "_"
+end
+
+function Strong(s)
+    return "**" .. s .. "**"
+end
+
+function Subscript(s)
+    return "_" .. s
+end
+
+function Superscript(s)
+    return "^" .. s
+end
+
+function SmallCaps(s)
+    return s
+end
+
+function Strikeout(s)
+    return '~~' .. s .. '~~'
+end
+
+function Link(s, tgt, tit, attr)
+    if tgt:match("%.html$") and not tgt:match("^https?://") then
+        tgt = tgt:gsub("%.html$", ".gmi")
+    end
+    table.insert(links, "=> " .. tgt .. " " .. s)
+    return s
+end
+
+function Image(s, src, tit, attr)
+    table.insert(links, "=> " .. src .. " [IMG] " .. s)
+    return s
+end
+
+function Code(s, attr)
+    return "`" .. s .. "`"
+end
+
+function InlineMath(s)
+    return "\\(" .. s .. "\\)"
+end
+
+function DisplayMath(s)
+    return "\\[" .. s .. "\\]"
+end
+
+function SingleQuoted(s)
+    return "‘" .. s .. "’"
+end
+
+function DoubleQuoted(s)
+    return "“" .. s .. "”"
+end
+
+function Note(s)
+    local num = #notes + 1
+    local num_fn = string.gsub(num, '0', '⁰')
+        :gsub('1', '¹')
+        :gsub('2', '²')
+        :gsub('3', '³')
+        :gsub('4', '⁴')
+        :gsub('5', '⁵')
+        :gsub('6', '⁶')
+        :gsub('7', '⁷')
+        :gsub('8', '⁸')
+        :gsub('9', '⁹')
+    -- add a list item with the note to the note table.
+    table.insert(notes, num_fn .. ' ' .. s)
+    -- return the footnote reference, linked to the note.
+    return num_fn
+end
+
+function Span(s, attr)
+    return s
+end
+
+function RawInline(format, str)
+    if format == "gemtext" then
+        return str
+    else
+        return ''
+    end
+end
+
+function Cite(s, cs)
+    local ids = {}
+    for _,cit in ipairs(cs) do
+        table.insert(ids, cit.citationId)
+    end
+    return s .. ids:concat(",")
+end
+
+function Plain(s)
+    return s
+end
+
+function Para(s)
+    local finished = s .. "\n"
+    if #links > 0 then
+        local link_text = links[1]:match('=> [^ ]+ (.+)')
+        if link_text == s and #links == 1 then
+            finished = links[1] .. "\n"
+        else
+            finished = finished .. table.concat(links, "\n") .. "\n"
+        end
+    end
+    links = {}
+    return finished
+end
+
+-- lev is an integer, the header level.
+function Header(lev, s, attr)
+    return string.rep("#", lev) .. " " .. s .. "\n"
+end
+
+function BlockQuote(s)
+    return "> " .. s:gsub("\n", "\n> "):gsub("\n> $", "\n")
+end
+
+function HorizontalRule()
+    return "-----\n"
+end
+
+function LineBlock(ls)
+    return table.concat(ls, '\n') .. "\n"
+end
+
+function CodeBlock(s, attr)
+    return "```\n" .. s .. "\n```\n"
+end
+
+function BulletList(items)
+    local buffer = {}
+    for _, item in pairs(items) do
+        local finished = false
+        if #links > 0 then
+            local link_text = links[1]:match('=> [^ ]+ (.+)')
+            if link_text == item then
+                table.insert(buffer, links[1])
+                table.remove(links, 1)
+                finished = true
+            end
+        end
+        if not finished then
+            table.insert(buffer, "* " .. item)
+            for _,link in pairs(links) do
+                table.insert(buffer, link)
+            end
+            links = {}
+        end
+    end
+    return table.concat(buffer, "\n") .. "\n"
+end
+
+function OrderedList(items)
+  local buffer = {}
+  for i, item in pairs(items) do
+    table.insert(buffer, i .. ". " .. item)
+  end
+  return table.concat(buffer, "\n") .. "\n"
+end
+
+function DefinitionList(items)
+  local buffer = {}
+  for _,item in pairs(items) do
+    local k, v = next(item)
+    table.insert(buffer, k .. ":\n" .. table.concat(v, "\n"))
+  end
+  return table.concat(buffer, "\n") .. "\n"
+end
+
+function CaptionedImage(src, tit, caption, attr)
+   return '=> ' .. src .. ' [IMG] ' .. caption .. '\n'
+end
+
+-- Caption is a string, aligns is an array of strings,
+-- widths is an array of floats, headers is an array of
+-- strings, rows is an array of arrays of strings.
+function Table(caption, aligns, widths, headers, rows)
+    local buffer = {}
+    local function add(s)
+        table.insert(buffer, s)
+    end
+    add("<table>")
+    if caption ~= "" then
+        add("<caption>" .. caption .. "</caption>")
+    end
+    if widths and widths[1] ~= 0 then
+        for _, w in pairs(widths) do
+            add('<col width="' .. string.format("%.0f%%", w * 100) .. '" />')
+        end
+    end
+    local header_row = {}
+    local empty_header = true
+    for i, h in pairs(headers) do
+        table.insert(header_row,'<th>' .. h .. '</th>')
+        empty_header = empty_header and h == ""
+    end
+    if empty_header then
+        head = ""
+    else
+        add('<tr class="header">')
+        for _,h in pairs(header_row) do
+            add(h)
+        end
+        add('</tr>')
+    end
+    local class = "even"
+    for _, row in pairs(rows) do
+        class = (class == "even" and "odd") or "even"
+        add('<tr class="' .. class .. '">')
+        for i,c in pairs(row) do
+            add('<td>' .. c .. '</td>')
+        end
+        add('</tr>')
+    end
+    add('</table>')
+    return table.concat(buffer,'\n') .. "\n"
+end
+
+function RawBlock(format, str)
+    if format == "gemtext" then
+        return str
+    else
+        return ''
+    end
+end
+
+function Div(s, attr)
+    return s
+end
+
+-- The following code will produce runtime warnings when you haven't defined
+-- all of the functions you need for the custom writer, so it's useful
+-- to include when you're working on a writer.
+local meta = {}
+meta.__index =
+    function(_, key)
+        io.stderr:write(string.format("WARNING: Undefined function '%s'\n",key))
+        return function() return "" end
+    end
+setmetatable(_G, meta)
-- 
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