From d8309be06a202b1bd6a9a2dd8eacc6e9b10e459b Mon Sep 17 00:00:00 2001
From: Hiroshi Shirosaki <h.shirosaki@gmail.com>
Date: Tue, 19 Jan 2016 18:18:04 +0900
Subject: [PATCH 1/1] Concealing links

Add conceal to syntax link to help readability.
Fix #244
---
 README.md           | 12 ++++++++++++
 syntax/markdown.vim | 13 ++++++++++---
 test/syntax.vader   | 14 ++++++++++++++
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 6020381..ec200b6 100644
--- a/README.md
+++ b/README.md
@@ -113,6 +113,18 @@ It never increases its default size (half screen), it only shrinks.
 let g:vim_markdown_toc_autofit = 1
 ```
 
+### Syntax Concealing
+
+Concealing is set for some syntax.
+
+For example, conceal `[link text](link url)` as just `link text`.
+
+To enable/disable conceal use Vim's standard conceal configuration.
+
+```vim
+set conceallevel = 2
+```
+
 ### Syntax extensions
 
 The following options control which syntax extensions will be turned on. They are off by default.
diff --git a/syntax/markdown.vim b/syntax/markdown.vim
index b812698..46eb5a9 100644
--- a/syntax/markdown.vim
+++ b/syntax/markdown.vim
@@ -34,6 +34,13 @@ syn spell toplevel
 syn case ignore
 syn sync linebreaks=1
 
+let s:conceal = ''
+let s:concealends = ''
+if has('conceal')
+  let s:conceal = ' conceal'
+  let s:concealends = ' concealends'
+endif
+
 "additions to HTML groups
 syn region htmlItalic start="\\\@<!\*\ze[^\\\*\t ]" end="[^\\\*\t ]\zs\*" keepend oneline
 syn region htmlItalic start="\\\@<!_\ze[^\\_\t ]" end="[^\\_\t ]\zs_" keepend oneline
@@ -44,9 +51,9 @@ syn region htmlBoldItalic start="___\ze\S" end="\S\zs___" keepend oneline
 
 " [link](URL) | [link][id] | [link][] | ![image](URL)
 syn region mkdFootnotes matchgroup=mkdDelimiter start="\[^"    end="\]"
-syn region mkdID matchgroup=mkdDelimiter        start="\["    end="\]" contained oneline
-syn region mkdURL matchgroup=mkdDelimiter       start="("     end=")"  contained oneline
-syn region mkdLink matchgroup=mkdDelimiter      start="\\\@<!!\?\[" end="\]\ze\s*[[(]" contains=@mkdNonListItem,@Spell nextgroup=mkdURL,mkdID skipwhite oneline
+execute 'syn region mkdID matchgroup=mkdDelimiter    start="\["    end="\]" contained oneline' . s:conceal
+execute 'syn region mkdURL matchgroup=mkdDelimiter   start="("     end=")"  contained oneline' . s:conceal
+execute 'syn region mkdLink matchgroup=mkdDelimiter  start="\\\@<!!\?\[" end="\]\ze\s*[[(]" contains=@mkdNonListItem,@Spell nextgroup=mkdURL,mkdID skipwhite oneline' . s:concealends
 
 " Autolink without angle brackets.
 " mkd  inline links:           protocol   optional  user:pass@       sub/domain                 .com, .co.uk, etc      optional port   path/querystring/hash fragment
diff --git a/test/syntax.vader b/test/syntax.vader
index 6f0a694..bdc599f 100644
--- a/test/syntax.vader
+++ b/test/syntax.vader
@@ -98,6 +98,20 @@ Execute (multiple links on a line):
   AssertNotEqual SyntaxOf('c'), 'mkdLink'
   AssertNotEqual SyntaxOf('c'), 'mkdURL'
 
+Given markdown;
+[a](b)
+
+Execute (conceal link):
+  setlocal conceallevel=2
+  AssertEqual synconcealed(1, 1)[0], 1
+  AssertEqual synconcealed(1, 2)[0], 0
+  AssertEqual synconcealed(1, 3)[0], 1
+  AssertEqual synconcealed(1, 4)[0], 1
+  AssertEqual synconcealed(1, 4)[0], 1
+  AssertEqual synconcealed(1, 5)[0], 1
+  AssertEqual synconcealed(1, 6)[0], 1
+  setlocal conceallevel=0
+
 # Autolinks
 
 Given markdown;
-- 
2.39.5