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| author | Bryce Kwon <bryce@brycekwon.com> | |
|---|---|---|
| committer | Bryce Kwon <bryce@brycekwon.com> | |
| commit | ||
| parent | ||
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| download | ||
Render more of the markdown seen in readmes
A line of equals signs or dashes under a paragraph now makes a heading
of it, as on GitHub, instead of running into its text, and any other
rule ends the paragraph. Four spaces or a tab start a code block, and an
escaped pipe stays in its table cell. A link opening with two slashes
or backslashes in any mix leads to another site, so it renders as text
like the plain scheme relative one already did.
| -rw-r--r-- | custom/extensions/about-render.lua | 124 | |
| -rw-r--r-- | tests/extensions/test-about-render.lua | 26 |
2 files changed, 131 insertions, 19 deletions
diff --git a/custom/extensions/about-render.lua b/custom/extensions/about-render.lua index d7753a3..040768c 100644 --- a/custom/extensions/about-render.lua +++ b/custom/extensions/about-render.lua @@ -81,11 +81,36 @@ local function split_lines(text) end end +-- A pipe escaped with a backslash belongs to its cell, even inside a code +-- span, so as on GitHub the backslash goes and the pipe stays. An even run of +-- backslashes escapes only itself, so the pipe after it still divides. local function split_cells(row) - row = trim(row):gsub("^|", ""):gsub("|$", "") - local cells = {} - for cell in (row .. "|"):gmatch("(.-)|") do - cells[#cells + 1] = trim(cell) + row = trim(row) + local cells, parts, start = {}, {}, 1 + if row:sub(1, 1) == "|" then + start = 2 + end + while true do + local bar = row:find("|", start, true) + if not bar then + break + end + local slashes = 0 + while row:sub(bar - slashes - 1, bar - slashes - 1) == "\\" do + slashes = slashes + 1 + end + if slashes % 2 == 1 then + parts[#parts + 1] = row:sub(start, bar - 2) .. "|" + else + parts[#parts + 1] = row:sub(start, bar - 1) + cells[#cells + 1] = trim(table.concat(parts)) + parts = {} + end + start = bar + 1 + end + if start <= #row or #parts > 0 then + parts[#parts + 1] = row:sub(start) + cells[#cells + 1] = trim(table.concat(parts)) end return cells end @@ -96,10 +121,11 @@ end -- so it is safe on Lua 5.1, where an embedded zero byte ends a pattern. local function safe_url(url) url = url:gsub("[%c%s]", "") - -- A leading "//" or "/\" is scheme-relative, which a browser - -- resolves to another origin, so it is not the local target the - -- parser meant to allow. - if url:sub(1, 2) == "//" or url:sub(1, 2) == "/\\" then + -- A leading "//" is scheme-relative, which a browser resolves to + -- another origin, and it reads a backslash there as a slash, so no + -- pair of the two is the local target the parser meant to allow. + local head = url:sub(1, 2):gsub("\\", "/") + if head == "//" then return nil end local scheme = url:match("^(%a[%w%+%.%-]*):") @@ -316,11 +342,10 @@ end -- Markdown is a deliberate subset rather than CommonMark, leaving out --- reference links, raw HTML passthrough, nested lists and setext headings, --- and inline markup does not span the end of a line. Man rendering covers the --- common macros and drops the rest. Both parse into a node tree before --- anything is emitted, so a failed parse falls back to plain text without --- leaving half a page behind. +-- reference links, raw HTML passthrough and nested lists, and inline markup +-- does not span the end of a line. Man rendering covers the common macros and +-- drops the rest. Both parse into a node tree before anything is emitted, so a +-- failed parse falls back to plain text without leaving half a page behind. local render_markdown, render_man @@ -428,6 +453,11 @@ if has_lpeg then local lang_char = R("az", "AZ", "09") + S("_.+#-") local heading_line = C(P("#") * P("#") ^ -5) * space ^ 1 * C(P(1) ^ 0) + -- A run of equals signs or dashes under a paragraph turns it into a + -- heading, as on GitHub, rather than reading as more of its text. + local setext_line = space ^ 0 * (C(P("=") ^ 1) + C(P("-") ^ 1)) + * space ^ 0 * eol + local code_indent = P(" ") + P("\t") local function thematic(mark) return space ^ 0 * P(mark) * (space ^ 0 * P(mark)) ^ 2 * space ^ 0 * eol end @@ -454,6 +484,28 @@ if has_lpeg then local function ordered(mark) return mark:match("%d") ~= nil end + local function follows_list(blocks) + local last = blocks[#blocks] + return last ~= nil and last.kind == "list" + end + + -- An indented block runs on through blank lines, and up to four spaces + -- or one tab come off each of its lines. + local function continues_code(line) + return code_indent:match(line) or not line:find("%S") + end + + local function unindent(line) + return line:match("^\t(.*)$") or line:match("^ ? ? ? ?(.*)$") + end + + local function setext_level(line) + local run = setext_line:match(line) + if run then + return run:sub(1, 1) == "=" and 1 or 2 + end + end + local function table_starts(lines, i) return i < #lines and lines[i]:find("|", 1, true) ~= nil and table_delimiter:match(lines[i + 1]) ~= nil @@ -589,17 +641,51 @@ if has_lpeg then ordered = is_ordered, items = items, } + -- Four spaces or a tab start a code block, except straight + -- after a list, where an indented paragraph more likely + -- carries an item on. + elseif code_indent:match(line) and not follows_list(blocks) then + local code = {} + while i <= n and continues_code(lines[i]) do + code[#code + 1] = unindent(lines[i]) + i = i + 1 + end + while code[#code]:match("^%s*$") do + code[#code] = nil + end + blocks[#blocks + 1] = { + kind = "code", + text = table.concat(code, "\n") .. "\n", + } else - local paragraph = { line } + local paragraph, level = { line }, nil i = i + 1 - while i <= n and not ends_paragraph(lines, i) do + while i <= n do + level = setext_level(lines[i]) + if level or ends_paragraph(lines, i) + or break_line:match(lines[i]) then + break + end paragraph[#paragraph + 1] = lines[i] i = i + 1 end - blocks[#blocks + 1] = { - kind = "para", - lines = paragraph_lines(paragraph), - } + if level then + local words = {} + for k, text in ipairs(paragraph) do + words[k] = trim(text) + end + blocks[#blocks + 1] = { + kind = "heading", + level = level, + kids = parse_inline(table.concat(words, " ")), + } + i = i + 1 + else + blocks[#blocks + 1] = { + kind = "para", + lines = paragraph_lines(paragraph), + } + end end end return blocks diff --git a/tests/extensions/test-about-render.lua b/tests/extensions/test-about-render.lua index a493720..0571796 100644 --- a/tests/extensions/test-about-render.lua +++ b/tests/extensions/test-about-render.lua @@ -257,6 +257,26 @@ render("README.md", string.rep("# a\n", 50000)) render("README.md", "| a | b |\n|---|---|\n| x" .. string.rep(" ", 40000) .. "y | z |") h.check("a long run of spaces is trimmed quickly", os.clock() - started < 10) +out = render("README.md", "Title\n=====\n\nBody") +h.contains("equals signs under a line make a heading", out, "<h1 id='title'>Title</h1><p>Body</p>") + +out = render("README.md", "Two\nlines\n---\nafter") +h.contains("dashes under a paragraph make a heading of it all", out, + "<h2 id='two-lines'>Two lines</h2><p>after</p>") + +out = render("README.md", "text\n***\nmore") +h.contains("a rule ends the paragraph above it", out, "<p>text</p><hr><p>more</p>") + +out = render("README.md", "Para\n\n code line\n\tnext <line>\n\nafter") +h.contains("an indented block renders as code", out, + "<p>Para</p><pre><code>code line\nnext <line>\n</code></pre><p>after</p>") + +out = render("README.md", "- item\n\n more about it") +h.excludes("an indented paragraph after a list stays prose", out, "<pre>") + +out = render("README.md", "[a](\\\\evil.example/x) [b](\\/evil.example/x)") +h.excludes("a scheme relative link spelt with backslashes renders no anchor", out, "<a ") + out = render("README.md", "| a | b |\n| --- | --- |\n| 1 | 2 |") h.contains("a pipe table renders its head", out, "<thead><tr><th>a</th><th>b</th></tr></thead>") h.contains("a pipe table renders its body", out, "<tbody><tr><td>1</td><td>2</td></tr></tbody>") @@ -267,6 +287,12 @@ h.contains("a table cuts a paragraph short", out, "<p>Pick one:</p><table><thead out = render("README.md", "a | b in prose") h.excludes("a pipe without a delimiter row stays prose", out, "<table") +out = render("README.md", "| a | b |\n|---|---|\n| x \\| y | `p \\| q` |") +h.contains("an escaped pipe stays in its cell", out, "<td>x | y</td><td><code>p | q</code></td>") + +out = render("README.md", "| a | b |\n|---|---|\n| x \\\\| y |") +h.contains("an escaped backslash still lets the pipe divide", out, "<td>x \\</td><td>y</td>") + out = render("README.md", "- first\n- second") h.contains("dashes render an unordered list", out, "<ul><li>first</li><li>second</li></ul>") |