Merge pull request #996 from arp242/rc

Revert "Permit more control characters in comments (#924)"

Author: pradyunsg

CHANGELOG.md

@@ -4,7 +4,6 @@
 
 - Clarify that comments never affect the tables produced by parsers.
 - Clarify Unicode and UTF-8 references.
-- 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

@@ -37,10 +37,11 @@ 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

@@ -57,9 +57,8 @@ key = "value"  # This is a comment at the end of a line
 another = "# This is not a comment"
 ```
 
-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.
+Control characters other than tab (U+0000 to U+0008, U+000A to U+001F, U+007F)
+are not permitted in comments.
 
 Comments should be used to communicate between the human readers of a file.
 Parsers must not modify keys or values, based on the presence (or contents) of a