Permit more control characters in comments

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## unreleased
 
+- Relax comment parsing; most control characters are again permitted.
 - Allow newline after key/values in inline tables.
 - Allow trailing comma in inline tables.
 - Clarify where and how dotted keys define tables.

toml.abnf

@@ -37,11 +37,10 @@ newline =/ %x0D.0A  ; CRLF
 
 ;; Comment
 
+comment = comment-start-symbol *allowed-comment-char
 comment-start-symbol = %x23 ; #
+allowed-comment-char = %x01-09 / %x0E-7F / non-ascii
 non-ascii = %x80-D7FF / %xE000-10FFFF
-non-eol = %x09 / %x20-7E / non-ascii
-
-comment = comment-start-symbol *non-eol
 
 ;; Key-Value pairs
 

toml.md

@@ -44,17 +44,16 @@ should be easy to parse into data structures in a wide variety of languages.
 ## Comment
 
 A hash symbol marks the rest of the line as a comment, except when inside a
-string.
+string. Comments may contain any Unicode code points except the following
+control codes that could cause problems during editing or processing: U+0000,
+and U+000A to U+000D.
 
 ```toml
 # This is a full-line comment
 key = "value"  # This is a comment at the end of a line
 another = "# This is not a comment"
 ```
 
-Control characters other than tab (U+0000 to U+0008, U+000A to U+001F, U+007F)
-are not permitted in comments.
-
 ## Key/Value Pair
 
 The primary building block of a TOML document is the key/value pair.