get rid of syntactically significant unicode equals signs (#400)

Fixes: #399

CHANGELOG.md

@@ -59,10 +59,6 @@
   whitespace matching the whitespace prefix of the closing line. Multiline
   strings and raw strings now must have a newline immediately following their
   opening `"`, and a final newline plus whitespace preceding the closing `"`.
-* SMALL EQUALS SIGN (`U+FE66`), FULLWIDTH EQUALS SIGN (`U+FF1D`), and HEAVY
-  EQUALS SIGN (`U+1F7F0`) are now treated the same as `=` and can be used for
-  properties (e.g. `お名前＝☜(ﾟヮﾟ☜)`). They are also no longer valid in bare
-  identifiers.
 * `.1`, `+.1` etc are no longer valid identifiers, to prevent confusion and
   conflicts with numbers.
 * Multi-line strings' literal Newline sequences are now normalized to single

README.md

@@ -158,11 +158,10 @@ node3 #"C:\Users\zkat\raw\string"#
 
 You don't have to quote strings unless any the following apply:
   * The string contains whitespace.
-  * The string contains any of `[]{}()\/#";`.
-  * The string is one of `true`, `false`, or `null`.
+  * The string contains any of `[]{}()\/#";=`.
+  * The string is one of `true`, `false`, `null`, `inf`, `-inf`, or `nan`.
   * The strings starts with a digit, or `+`/`-`/`.`/`-.`,`+.` and a digit.
-  * The string contains an equals sign (including unicode equals signs `﹦`,
-    `＝`, and `🟰`).
+    (aka "looks like a number")
 
 In essence, if it can get confused for other KDL or KQL syntax, it needs
 quotes.
@@ -296,8 +295,8 @@ smile 😁
 // Identifiers are very flexible. The following is a legal bare identifier:
 <@foo123~!$%^&*.:'|?+>
 
-// And you can also use unicode, even for the equals sign!
-ノード　お名前＝☜(ﾟヮﾟ☜)
+// And you can also use unicode!
+ノード　お名前=ฅ^•ﻌ•^ฅ
 
 // kdl specifically allows properties and values to be
 // interspersed with each other, much like CLI commands.
@@ -335,9 +334,9 @@ SDLang, but that had some design choices I disagreed with.
 
 #### Ok, then, why not SDLang?
 
-SDLang is designed for use cases that are not interesting to me, but are very
-relevant to the D-lang community. KDL is very similar in many ways, but is
-different in the following ways:
+SDLang is an excellent base, but I wanted some details ironed out, and some
+things removed that only really made sense for SDLang's current use-cases, including
+some restrictions about data representation. KDL is very similar in many ways, except:
 
 * The grammar and expected semantics are [well-defined and specified](SPEC.md).
 * There is only one "number" type. KDL does not prescribe representations.

SPEC.md

@@ -112,8 +112,8 @@ my-node 1 2 \  // comments are ok after \
 ### Property
 
 A Property is a key/value pair attached to a [Node](#node). A Property is
-composed of a [String](#string), followed immediately by an [equals
-sign](#equals-sign), and then a [Value](#value).
+composed of a [String](#string), followed immediately by an equals sign (`=`, `U+003D`),
+and then a [Value](#value).
 
 Properties should be interpreted left-to-right, with rightmost properties with
 identical names overriding earlier properties. That is:
@@ -131,17 +131,6 @@ still be spec-compliant.
 Properties _MAY_ be prefixed with `/-` to "comment out" the entire token and
 make it act as plain whitespace, even if it spreads across multiple lines.
 
-#### Equals Sign
-
-Any of the following characters may be used as equals signs in properties:
-
-| Name | Character | Code Point |
-|----|-----|----|
-| EQUALS SIGN | `=` | `U+003D` |
-| SMALL EQUALS SIGN | `﹦` | `U+FE66` |
-| FULLWIDTH EQUALS SIGN | `＝` | `U+FF1D` |
-| HEAVY EQUALS SIGN | `🟰` | `U+1F7F0` |
-
 ### Argument
 
 An Argument is a bare [Value](#value) attached to a [Node](#node), with no
@@ -334,8 +323,7 @@ negative number.
 
 The following characters cannot be used anywhere in a [Identifier String](#identifier-string):
 
-* Any of `(){}[]/\"#;`
-* Any [Equals Sign](#equals-sign)
+* Any of `(){}[]/\"#;=`
 * Any [Whitespace](#whitespace) or [Newline](#newline).
 * Any [disallowed literal code points](#disallowed-literal-code-points) in KDL
   documents.
@@ -780,19 +768,17 @@ node-prop-or-arg := prop | value
 node-children := '{' nodes final-node? '}'
 node-terminator := single-line-comment | newline | ';' | eof
 
-prop := string optional-node-space equals-sign optional-node-space value
+prop := string optional-node-space '=' optional-node-space value
 value := type? optional-node-space (string | number | keyword)
 type := '(' optional-node-space string optional-node-space ')'
 
-equals-sign := See Table ([Equals Sign](#equals-sign))
-
 string := identifier-string | quoted-string | raw-string
 
 identifier-string := unambiguous-ident | signed-ident | dotted-ident
 unambiguous-ident := ((identifier-char - digit - sign - '.') identifier-char*) - 'true' - 'false' - 'null' - 'inf' - '-inf' - 'nan'
 signed-ident := sign ((identifier-char - digit - '.') identifier-char*)?
 dotted-ident := sign? '.' ((identifier-char - digit) identifier-char*)?
-identifier-char := unicode - unicode-space - newline - [\\/(){};\[\]"#] - disallowed-literal-code-points - equals-sign
+identifier-char := unicode - unicode-space - newline - [\\/(){};\[\]"#=] - disallowed-literal-code-points
 
 quoted-string := '"' (single-line-string-body | newline multi-line-string-body newline unicode-space*) '"'
 single-line-string-body := (string-character - newline)*

tests/test_cases/expected_kdl/unicode_equals_signs.kdl

@@ -1 +0,0 @@
-node p1=val1 p2=val2 p3=val3

tests/test_cases/expected_kdl/unicode_silly.kdl

@@ -0,0 +1 @@
+ノード　お名前=ฅ^•ﻌ•^ฅ

tests/test_cases/input/unicode_equals_signs.kdl

@@ -1,4 +0,0 @@
-node \
-    p1﹦val1 \ // U+FE66
-    p2＝val2 \ // U+FF1D
-    p3🟰val3 // U+1F7F0

tests/test_cases/input/unicode_silly.kd

@@ -0,0 +1 @@
+ノード　お名前=ฅ^•ﻌ•^ฅ