runtime(cangjie): Fixes and improvements for syntax script

Housekeeping:
- Add GitHub repository link
- Update Last Change date

Style:
- Add Vim modeline for consistent formatting
- Unify indentation style (spaces to tabs)
- Wrap long cluster definitions for readability

New Features:
- Add highlighting for escape sequences
- Add error highlighting for invalid rune literals
- Add syntax-based folding support

Fixes:
- Fix rune matching to allow only a single character/escape
- Fix highlighting for double-quoted rune literals
- Fix highlighting for floats with exponents and type suffixes

Co-authored-by: dkearns <dougkearns@gmail.com>
Signed-off-by: Wu Junkai <wujunkai20041123@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/cangjie.vim

@@ -1,7 +1,8 @@
 " Vim syntax file
 " Language: Cangjie
 " Maintainer: Wu Junkai <wu.junkai@qq.com>
-" Last Change: 2025 Aug 17
+" URL: https://github.com/WuJunkai2004/cangjie.vim
+" Last Change: 2025 Oct 12
 "
 " The Cangjie programming language is a new-generation programming
 " language oriented to full-scenario intelligence. It features
@@ -47,7 +48,12 @@ syn keyword cangjieIdentlike	false init main this true
 syn keyword cangjieVariable	const let var
 syn keyword cangjieOption	Option Some None
 syn keyword cangjieDeclaration	func struct class enum import package nextgroup=cangjieTypeName skipwhite
-syn cluster cangjieKeywordCluster	contains=cangjieDeclaration,cangjieStatement,cangjieIdentlike,cangjieVariable,cangjieOption
+syn cluster cangjieKeywordCluster contains=
+	\ cangjieDeclaration,
+	\ cangjieStatement,
+	\ cangjieIdentlike,
+	\ cangjieVariable,
+	\ cangjieOption
 
 " 3. macro (e.g., @override)
 syn match cangjieMacro /@\h\w*/
@@ -66,30 +72,54 @@ syn keyword cangjieCommonType	Bool Byte Rune String
 syn keyword cangjieFloatType	Float16 Float32 Float64
 syn keyword cangjieIntType	Int8 Int16 Int32 Int64 IntNative
 syn keyword cangjieUIntType	UInt8 UInt16 UInt32 UInt64 UIntNative
-syn cluster cangjieTypeCluster contains=cangjieSpType,cangjieArrayType,cangjieHashType,cangjieCommonType,cangjieFloatType,cangjieIntType,cangjieUIntType
+syn cluster cangjieTypeCluster contains=
+	\ cangjieSpType,
+	\ cangjieArrayType,
+	\ cangjieHashType,
+	\ cangjieCommonType,
+	\ cangjieFloatType,
+	\ cangjieIntType,
+	\ cangjieUIntType
 
 " 7. character and strings
-syn cluster cangjieInterpolatedPart contains=@cangjieKeywordCluster,cangjieSpIdentifier,@cangjieTypeCluster,@cangjieNumberCluster,cangjieOperator
+syn cluster cangjieInterpolatedPart contains=
-syn region  cangjieInterpolation contained keepend start=/\${/ end=/}/ contains=@cangjieInterpolatedPart matchgroup=cangjieInterpolationDelimiter
+	\ @cangjieKeywordCluster,
-syn region cangjieRune   start=/r'/ skip=/\\\\\|\\'/ end=/'/ oneline
+	\ cangjieSpIdentifier,
-syn region cangjieRune   start=/b'/ skip=/\\\\\|\\'/ end=/'/ oneline
+	\ @cangjieTypeCluster,
-syn region cangjieString start=/"/ skip=/\\\\\|\\"/ end=/"/ oneline contains=cangjieInterpolation
+	\ @cangjieNumberCluster,
-syn region cangjieString start=/'/ skip=/\\\\\|\\'/ end=/'/ oneline contains=cangjieInterpolation
+	\ cangjieOperator
-syn region cangjieString start=/"""/ skip=/\\\\\|\\"/ end=/"""/ contains=cangjieInterpolation keepend
+syn region  cangjieInterpolation contained keepend start=/\${/ end=/}/ contains=@cangjieInterpolatedPart
-syn region cangjieString start=/'''/ skip=/\\\\\|\\'/ end=/'''/ contains=cangjieInterpolation keepend
+syn match cangjieEscape /\v\\u\{[0-9a-fA-F]{1,8}\}|\\./ contained
+syn match cangjieRuneError /\v[rb]'([^'\\]|\\.)*'/
+syn match cangjieRuneError /\v[rb]"([^"\\]|\\.)*"/
+syn match cangjieRune /\vr'(\\u\{[0-9a-fA-F]{1,8}\}|\\.|[^'\\])'/ contains=cangjieEscape
+syn match cangjieRune /\vr"(\\u\{[0-9a-fA-F]{1,8}\}|\\.|[^"\\])"/ contains=cangjieEscape
+syn match cangjieRune /\vb'(\\u\{[0-9a-fA-F]{1,8}\}|\\.|[^'\\])'/ contains=cangjieEscape
+syn region cangjieString start=/"/ skip=/\\\\\|\\"/ end=/"/ oneline contains=cangjieInterpolation,cangjieEscape
+syn region cangjieString start=/'/ skip=/\\\\\|\\'/ end=/'/ oneline contains=cangjieInterpolation,cangjieEscape
+syn region cangjieString start=/"""/ skip=/\\\\\|\\"/ end=/"""/ contains=cangjieInterpolation,cangjieEscape keepend
+syn region cangjieString start=/'''/ skip=/\\\\\|\\'/ end=/'''/ contains=cangjieInterpolation,cangjieEscape keepend
 syn region cangjieRawString start='\z(#*\)#"'  end='"#\z1'
 syn region cangjieRawString start='\z(#*\)#\'' end='\'#\z1'
 
 " 8. number
+syn match cangjieHexFloatNumber	/\v\c<0x([0-9a-f_]+\.?|[0-9a-f_]*\.[0-9a-f_]+)[p][-+]?\d[0-9_]*>/
 syn match cangjieFloatNumber	/\v\c<\d[0-9_]*\.\d[0-9_]*([ep][-+]?\d[0-9_]*)?(f(16|32|64))?>/
 syn match cangjieFloatNumber	/\v\c<\d[0-9_]*\.([ep][-+]?\d[0-9_]*)?(f(16|32|64))?>/
 syn match cangjieFloatNumber	/\v\c\.\d[0-9_]*([ep][-+]?\d[0-9_]*)?(f(16|32|64))?>/
-syn match cangjieScienceNumber	/\v\c<\d[0-9_]*[e][-+]?\d[0-9_]*>/
+syn match cangjieScienceNumber	/\v\c<\d[0-9_]*[e][-+]?\d[0-9_]*(f(16|32|64))?>/
 syn match cangjieHexNumber	/\v\c<0x[0-9a-f_]+([iu](8|16|32|64))?>/
 syn match cangjieOctalNumber	/\v\c<0o[0-7_]+([iu](8|16|32|64))?>/
 syn match cangjieBinaryNumber	/\v\c<0b[01_]+([iu](8|16|32|64))?>/
 syn match cangjieDecimalNumber	/\v\c<\d[0-9_]*([iu](8|16|32|64))?>/
-syn cluster cangjieNumberCluster contains=cangjieFloatNumber,cangjieScienceNumber,cangjieHexNumber,cangjieOctalNumber,cangjieBinaryNumber,cangjieDecimalNumber
+syn cluster cangjieNumberCluster contains=
+	\ cangjieHexFloatNumber,
+	\ cangjieFloatNumber,
+	\ cangjieScienceNumber,
+	\ cangjieHexNumber,
+	\ cangjieOctalNumber,
+	\ cangjieBinaryNumber,
+	\ cangjieDecimalNumber
 
 " 9. operators
 syn match cangjieOperator /[-+%<>!&|^*=]=\?/
@@ -101,6 +131,11 @@ syn match cangjieOperator /[:]/
 syn match cangjieOperator /\.\./
 syn match cangjieVarArgs  /\.\.\./
 
+" 10. folding
+syn region cangjieFoldBraces transparent fold start='{' end='}' contains=ALLBUT,cangjieComment
+syn region cangjieFoldParens transparent fold start='(' end=')' contains=ALLBUT,cangjieComment
+syn region cangjieFoldBrackets transparent fold start='\[' end='\]' contains=ALLBUT,cangjieComment
+
 " finally, link the syntax groups to the highlight groups
 if s:enabled('comment')
 	hi def link cangjieTodo			Todo
@@ -120,6 +155,7 @@ if s:enabled('macro')
 	hi def link cangjieMacro		PreProc
 endif
 if s:enabled('number')
+	hi def link cangjieHexFloatNumber	Number
 	hi def link cangjieFloatNumber		Float
 	hi def link cangjieScienceNumber	Float
 	hi def link cangjieHexNumber		Number
@@ -133,8 +169,10 @@ if s:enabled('operator')
 endif
 if s:enabled('string')
 	hi def link cangjieRune			Character
+	hi def link cangjieRuneError		Error
 	hi def link cangjieString		String
 	hi def link cangjieRawString		String
+	hi def link cangjieEscape		SpecialChar
 endif
 if s:enabled('type')
 	hi def link cangjieTypeName		Type
@@ -151,3 +189,5 @@ let b:current_syntax = "cangjie"
 
 let &cpo = s:save_cpo
 unlet s:save_cpo
+
+" vim: ts=8 sw=8 noet