2 files changed, 43 insertions, 13 deletions
diff --git a/custom/extensions/about-render.lua b/custom/extensions/about-render.lua
index 9d5f72d..af18d1b 100644
--- a/custom/extensions/about-render.lua
+++ b/custom/extensions/about-render.lua
@@ -166,6 +166,8 @@ emit_inline = function(list)
 		local kind = node.kind
 		if kind == "text" then
 			html_txt(node.text)
+		elseif kind == "break" then
+			html("<br>")
 		elseif kind == "code" then
 			html("<code>"); html_txt(node.text); html("</code>")
 		elseif kind == "strong" then
@@ -255,7 +257,7 @@ emit_blocks = function(blocks)
 			html("<p>")
 			for i, line in ipairs(block.lines) do
 				if i > 1 then
-					html("<br>")
+					html("\n")
 				end
 				emit_inline(line)
 			end
@@ -274,7 +276,7 @@ end
 
 -- Markdown is a deliberate subset rather than CommonMark, leaving out
 -- reference links, raw HTML passthrough, nested lists and setext headings,
--- and emphasis does not span a hard line break. Man rendering covers the
+-- 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.
@@ -375,6 +377,28 @@ if has_lpeg then
 
 	local function ordered(mark) return mark:match("%d") ~= nil end
 
+	-- A paragraph's lines run together the way GitHub shows them, unless one
+	-- ends in two spaces or a backslash, which breaks the line there. The
+	-- last line of a paragraph has nothing to break before.
+	local function paragraph_lines(raw)
+		local lines = {}
+		for i, line in ipairs(raw) do
+			local hard = false
+			if i < #raw then
+				if line:sub(-1) == "\\" then
+					line, hard = line:sub(1, -2), true
+				else
+					hard = line:sub(-2) == "  "
+				end
+			end
+			lines[i] = parse_inline(trim(line))
+			if hard then
+				lines[i][#lines[i] + 1] = { kind = "break" }
+			end
+		end
+		return lines
+	end
+
 	local parse_blocks
 
 	parse_blocks = function(lines, depth)
@@ -426,13 +450,9 @@ if has_lpeg then
 						blocks = parse_blocks(inner, depth + 1),
 					}
 				else
-					local paragraph = {}
-					for _, quoted in ipairs(inner) do
-						paragraph[#paragraph + 1] = parse_inline(quoted)
-					end
 					blocks[#blocks + 1] = {
 						kind = "para",
-						lines = paragraph,
+						lines = paragraph_lines(inner),
 					}
 				end
 			elseif i + 1 <= n and line:find("|", 1, true) and table_delimiter:match(lines[i + 1]) then
@@ -472,13 +492,16 @@ if has_lpeg then
 					items = items,
 				}
 			else
-				local paragraph = { parse_inline(line) }
+				local paragraph = { line }
 				i = i + 1
 				while i <= n and not lines[i]:match("^%s*$") and not block_start:match(lines[i]) do
-					paragraph[#paragraph + 1] = parse_inline(lines[i])
+					paragraph[#paragraph + 1] = lines[i]
 					i = i + 1
 				end
-				blocks[#blocks + 1] = { kind = "para", lines = paragraph }
+				blocks[#blocks + 1] = {
+					kind = "para",
+					lines = paragraph_lines(paragraph),
+				}
 			end
 		end
 		return blocks
diff --git a/tests/extensions/test-about-render.lua b/tests/extensions/test-about-render.lua
index 801cc45..b7d12c7 100644
--- a/tests/extensions/test-about-render.lua
+++ b/tests/extensions/test-about-render.lua
@@ -88,10 +88,17 @@ out = render("readme.markdown", "# Long")
 h.contains("the long markdown extension dispatches too", out, "<h1>Long</h1>")
 
 out = render("README.md", "line one\nline two")
-h.contains("a paragraph keeps its line break", out, "<p>line one<br>line two</p>")
+h.contains("the lines of a paragraph run together", out, "<p>line one\nline two</p>")
 
 out = render("README.md", "first para\r\nsecond line")
-h.contains("crlf line endings are normalised", out, "<p>first para<br>second line</p>")
+h.contains("crlf line endings are normalised", out, "<p>first para\nsecond line</p>")
+
+out = render("README.md", "one  \ntwo\\\nthree")
+h.contains("two trailing spaces break the line", out, "<p>one<br>\ntwo")
+h.contains("a trailing backslash breaks the line", out, "two<br>\nthree</p>")
+
+out = render("README.md", "spaces  \n\nslash\\")
+h.contains("the last line takes no break", out, "<p>spaces</p><p>slash\\</p>")
 
 out = render("README.md", "a **bold** and *leaning* word")
 h.contains("double stars embolden", out, "<strong>bold</strong>")
@@ -239,7 +246,7 @@ out = render("page.3", ".SS Details")
 h.contains("a subsection renders one level down", out, "<h3>Details</h3>")
 
 out = render("page.1", ".B bold words\nplain after")
-h.contains("the bold macro renders strong", out, "<p><strong>bold words</strong><br>plain after</p>")
+h.contains("the bold macro renders strong", out, "<p><strong>bold words</strong>\nplain after</p>")
 
 out = render("page.1", "a \\fBbold\\fR c")
 h.contains("font escapes carry across a run", out, "<p>a <strong>bold</strong> c</p>")