Backout Unicode bare keys

CHANGELOG.md

@@ -10,7 +10,6 @@
 - Add new `\e` shorthand for the escape character.
 - Add \x00 notation to basic strings.
 - Seconds in Date-Time and Time values are now optional.
-- Allow non-English scripts in unquoted (bare) keys
 - Clarify newline normalization in multi-line literal strings.
 
 ## 1.0.0 / 2021-01-11

toml.abnf

@@ -49,19 +49,7 @@ key = simple-key / dotted-key
 val = string / boolean / array / inline-table / date-time / float / integer
 
 simple-key = quoted-key / unquoted-key
-
-;; Unquoted key
-
-unquoted-key = 1*unquoted-key-char
-unquoted-key-char = ALPHA / DIGIT / %x2D / %x5F         ; a-z A-Z 0-9 - _
-unquoted-key-char =/ %xB2 / %xB3 / %xB9 / %xBC-BE       ; superscript digits, fractions
-unquoted-key-char =/ %xC0-D6 / %xD8-F6 / %xF8-37D       ; non-symbol chars in Latin block
-unquoted-key-char =/ %x37F-1FFF                         ; exclude GREEK QUESTION MARK, which is basically a semi-colon
-unquoted-key-char =/ %x200C-200D / %x203F-2040          ; from General Punctuation Block, include the two tie symbols and ZWNJ, ZWJ
-unquoted-key-char =/ %x2070-218F / %x2460-24FF          ; include super-/subscripts, letterlike/numberlike forms, enclosed alphanumerics
-unquoted-key-char =/ %x2C00-2FEF / %x3001-D7FF          ; skip arrows, math, box drawing etc, skip 2FF0-3000 ideographic up/down markers and spaces
-unquoted-key-char =/ %xF900-FDCF / %xFDF0-FFFD          ; skip D800-DFFF surrogate block, E000-F8FF Private Use area, FDD0-FDEF intended for process-internal use (unicode)
-unquoted-key-char =/ %x10000-EFFFF                      ; all chars outside BMP range, excluding Private Use planes (F0000-10FFFF)
+unquoted-key = 1*( ALPHA / DIGIT / %x2D / %x5F ) ; A-Z / a-z / 0-9 / - / _
 
 ;; Quoted and dotted key
 

toml.md

@@ -103,11 +103,9 @@ first = "Tom" last = "Preston-Werner" # INVALID
 
 A key may be either bare, quoted, or dotted.
 
-**Bare keys** may contain any letter-like or number-like Unicode character from
-any Unicode script, as well as ASCII digits, dashes and underscores.
-Punctuation, spaces, arrows, box drawing and private use characters are not
-allowed. Note that bare keys are allowed to be composed of only ASCII digits,
-e.g. 1234, but are always interpreted as strings.
+**Bare keys** may only contain ASCII letters, ASCII digits, underscores, and
+dashes (`A-Za-z0-9_-`). Note that bare keys are allowed to be composed of only
+ASCII digits, e.g. `1234`, but are always interpreted as strings.
 
 ℹ️ The exact ranges of allowed code points can be found in the
 [ABNF grammar file][abnf].
@@ -117,23 +115,18 @@ key = "value"
 bare_key = "value"
 bare-key = "value"
 1234 = "value"
-Fuß = "value"
-😂 = "value"
-汉语大字典 = "value"
-辭源 = "value"
-பெண்டிரேம் = "value"
 ```
 
 **Quoted keys** follow the exact same rules as either basic strings or literal
-strings and allow you to use any Unicode character in a key name, including
-spaces. Best practice is to use bare keys except when absolutely necessary.
+strings and allow you to use a much broader set of key names. Best practice is
+to use bare keys except when absolutely necessary.
 
 ```toml
 "127.0.0.1" = "value"
 "character encoding" = "value"
+"ʎǝʞ" = "value"
+'key2' = "value"
 'quoted "value"' = "value"
-"╠═╣" = "value"
-"⋰∫∬∭⋱" = "value"
 ```
 
 A bare key must be non-empty, but an empty quoted key is allowed (though
@@ -154,7 +147,6 @@ name = "Orange"
 physical.color = "orange"
 physical.shape = "round"
 site."google.com" = true
-பெண்.டிரேம் = "we are women"
 ```
 
 In JSON land, that would give you the following structure:
@@ -168,9 +160,6 @@ In JSON land, that would give you the following structure:
   },
   "site": {
     "google.com": true
-  },
-  "பெண்": {
-    "டிரேம்": "we are women"
   }
 }
 ```