From 25a86fc06fd5d7e07251ca9bd758cc42c4234d70 Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Wed, 27 Oct 2021 12:06:29 -0700
Subject: Markdown writer: Be sure to quote special values in YAML metadata.
E.g. "Y", "yes", which are now (with yaml library) considered
boolean values, as well as "null".
This fixes a bug with roundtripping markdown -> markdown:
```
---
foo: "true"
...
```
---
src/Text/Pandoc/Writers/Markdown.hs | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
(limited to 'src')
diff --git a/src/Text/Pandoc/Writers/Markdown.hs b/src/Text/Pandoc/Writers/Markdown.hs
index f03dc375d..4f6a8bfb1 100644
--- a/src/Text/Pandoc/Writers/Markdown.hs
+++ b/src/Text/Pandoc/Writers/Markdown.hs
@@ -140,10 +140,20 @@ valToYaml (SimpleVal x)
| otherwise =
if hasNewlines x
then hang 0 ("|" <> cr) x
- else if isNothing $ foldM needsDoubleQuotes True x
- then "\"" <> fmap escapeInDoubleQuotes x <> "\""
- else x
+ else case x of
+ Text _ t | isSpecialString t ->
+ "\"" <> fmap escapeInDoubleQuotes x <> "\""
+ _ | isNothing (foldM needsDoubleQuotes True x) ->
+ "\"" <> fmap escapeInDoubleQuotes x <> "\""
+ | otherwise -> x
where
+ isSpecialString t = Set.member t specialStrings
+ specialStrings = Set.fromList
+ ["y", "Y", "yes", "Yes", "YES", "n", "N",
+ "no", "No", "NO", "true", "True", "TRUE",
+ "false", "False", "FALSE", "on", "On", "ON",
+ "off", "Off", "OFF", "null", "Null",
+ "NULL", "~", "*"]
needsDoubleQuotes isFirst t
= if T.any isBadAnywhere t ||
(isFirst && T.any isYamlPunct (T.take 1 t))
--
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