From c47090d4bba7415e9b628fd92efee6f446d241a5 Mon Sep 17 00:00:00 2001
From: Michael Hatherly <michaelhatherly@gmail.com>
Date: Wed, 16 Mar 2016 12:10:42 +0200
Subject: [PATCH] Use "sidebars" for markdown tables.

Adds `|` columns on each side of markdown tables to avoid trailing
whitespace problems in rendered documents. This is still valid markdown.

This does not change the parsing of markdown tables, which can still
be written without the `|` columns on each side.

(cherry picked from commit 14a4feda57839182244881da0cebebf80126a37a)
ref #15530
---
 base/markdown/GitHub/table.jl | 14 ++++++++------
 test/markdown.jl              | 30 +++++++++++++++++++++++++-----
 2 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/base/markdown/GitHub/table.jl b/base/markdown/GitHub/table.jl
index baedbdf987eaa..2ef25a0d1ef72 100644
--- a/base/markdown/GitHub/table.jl
+++ b/base/markdown/GitHub/table.jl
@@ -97,20 +97,22 @@ function padcells!(rows, align; len = length, min = 0)
 end
 
 _dash(width, align) =
-    align == :l ? ":" * "-"^(width-1) :
-    align == :r ? "-"^(width-1) * ":" :
-    align == :c ? ":" * "-"^(width-2) * ":" :
+    align == :l ? ":" * "-"^width * " " :
+    align == :r ? " " * "-"^width * ":" :
+    align == :c ? ":" * "-"^width * ":" :
     throw(ArgumentError("Invalid alignment $align"))
 
 function plain(io::IO, md::Table)
     cells = mapmap(plaininline, md.rows)
     padcells!(cells, md.align, len = length, min = 3)
     for i = 1:length(cells)
+        print(io, "| ")
         print_joined(io, cells[i], " | ")
-        println(io)
+        println(io, " |")
         if i == 1
-            print_joined(io, [_dash(length(cells[i][j]), md.align[j]) for j = 1:length(cells[1])], " | ")
-            println(io)
+            print(io, "|")
+            print_joined(io, [_dash(length(cells[i][j]), md.align[j]) for j = 1:length(cells[1])], "|")
+            println(io, "|")
         end
     end
 end
diff --git a/test/markdown.jl b/test/markdown.jl
index 2e015f6b722dc..87c3d08902805 100644
--- a/test/markdown.jl
+++ b/test/markdown.jl
@@ -278,12 +278,32 @@ no|table
 no error
 """ == MD([Paragraph(Any["no|table no error"])])
 
-t = """a   |   b
-:-- | --:
-1   |   2
-"""
-@test plain(Markdown.parse(t)) == t
+let t = """a   |   b
+    :-- | --:
+    1   |   2
+    """
+    @test Markdown.parse(t) == MD(Table(Any[Any["a", "b"], Any["1", "2"]], [:l, :r]))
+end
 
+let text =
+    """
+    | a   |   b |
+    |:--- | ---:|
+    | 1   |   2 |
+    """,
+    table = Markdown.parse(text)
+    @test text == Markdown.plain(table)
+end
+let text =
+    """
+    | Markdown | Table |  Test |
+    |:-------- |:-----:| -----:|
+    | foo      | `bar` | *baz* |
+    | `bar`    |  baz  | *foo* |
+    """,
+    table = Markdown.parse(text)
+    @test text == Markdown.plain(table)
+end
 
 # LaTeX extension
 latex_doc = md"""