" Vim syntax file
" Language:		Haskell
" Maintainer:		Haskell Cafe mailinglist <haskell-cafe@haskell.org>
" Last Change:		2017 Dec 16
" Original Author:	John Williams <jrw@pobox.com>
"
" Thanks to Ryan Crumley for suggestions and John Meacham for
" pointing out bugs. Also thanks to Ian Lynagh and Donald Bruce Stewart
" for providing the inspiration for the inclusion of the handling
" of C preprocessor directives, and for pointing out a bug in the
" end-of-line comment handling.
"
" Options-assign a value to these variables to turn the option on:
"
" hs_highlight_delimiters - Highlight delimiter characters--users
"			    with a light-colored background will
"			    probably want to turn this on.
" hs_highlight_boolean - Treat True and False as keywords.
" hs_highlight_types - Treat names of primitive types as keywords.
" hs_highlight_more_types - Treat names of other common types as keywords.
" hs_highlight_debug - Highlight names of debugging functions.
" hs_allow_hash_operator - Don't highlight seemingly incorrect C
"			   preprocessor directives but assume them to be
"			   operators
"
" 2004 Feb 19: Added C preprocessor directive handling, corrected eol comments
"	       cleaned away literate haskell support (should be entirely in
"	       lhaskell.vim)
" 2004 Feb 20: Cleaned up C preprocessor directive handling, fixed single \
"	       in eol comment character class
" 2004 Feb 23: Made the leading comments somewhat clearer where it comes
"	       to attribution of work.
" 2008 Dec 15: Added comments as contained element in import statements

" quit when a syntax file was already loaded
if exists("b:current_syntax")
  finish
endif

" (Qualified) identifiers (no default highlighting)
syn match ConId "\(\<[A-Z][a-zA-Z0-9_']*\.\)\=\<[A-Z][a-zA-Z0-9_']*\>"
syn match VarId "\(\<[A-Z][a-zA-Z0-9_']*\.\)\=\<[a-z][a-zA-Z0-9_']*\>"

" Infix operators--most punctuation characters and any (qualified) identifier
" enclosed in `backquotes`. An operator starting with : is a constructor,
" others are variables (e.g. functions).
syn match hsVarSym "\(\<[A-Z][a-zA-Z0-9_']*\.\)\=[-!#$%&\*\+/<=>\?@\\^|~.][-!#$%&\*\+/<=>\?@\\^|~:.]*"
syn match hsConSym "\(\<[A-Z][a-zA-Z0-9_']*\.\)\=:[-!#$%&\*\+./<=>\?@\\^|~:]*"
syn match hsVarSym "`\(\<[A-Z][a-zA-Z0-9_']*\.\)\=[a-z][a-zA-Z0-9_']*`"
syn match hsConSym "`\(\<[A-Z][a-zA-Z0-9_']*\.\)\=[A-Z][a-zA-Z0-9_']*`"

" Reserved symbols--cannot be overloaded.
syn match hsDelimiter  "(\|)\|\[\|\]\|,\|;\|_\|{\|}"

" Strings and constants
syn match   hsSpecialChar	contained "\\\([0-9]\+\|o[0-7]\+\|x[0-9a-fA-F]\+\|[\"\\'&\\abfnrtv]\|^[A-Z^_\[\\\]]\)"
syn match   hsSpecialChar	contained "\\\(NUL\|SOH\|STX\|ETX\|EOT\|ENQ\|ACK\|BEL\|BS\|HT\|LF\|VT\|FF\|CR\|SO\|SI\|DLE\|DC1\|DC2\|DC3\|DC4\|NAK\|SYN\|ETB\|CAN\|EM\|SUB\|ESC\|FS\|GS\|RS\|US\|SP\|DEL\)"
syn match   hsSpecialCharError	contained "\\&\|'''\+"
syn region  hsString		start=+"+  skip=+\\\\\|\\"+  end=+"+  contains=hsSpecialChar
syn match   hsCharacter		"[^a-zA-Z0-9_']'\([^\\]\|\\[^']\+\|\\'\)'"lc=1 contains=hsSpecialChar,hsSpecialCharError
syn match   hsCharacter		"^'\([^\\]\|\\[^']\+\|\\'\)'" contains=hsSpecialChar,hsSpecialCharError
syn match   hsNumber		"\v<[0-9]%(_*[0-9])*>|<0[xX]_*[0-9a-fA-F]%(_*[0-9a-fA-F])*>|<0[oO]_*%(_*[0-7])*>|<0[bB]_*[01]%(_*[01])*>"
syn match   hsFloat		"\v<[0-9]%(_*[0-9])*\.[0-9]%(_*[0-9])*%(_*[eE][-+]?[0-9]%(_*[0-9])*)?>|<[0-9]%(_*[0-9])*_*[eE][-+]?[0-9]%(_*[0-9])*>|<0[xX]_*[0-9a-fA-F]%(_*[0-9a-fA-F])*\.[0-9a-fA-F]%(_*[0-9a-fA-F])*%(_*[pP][-+]?[0-9]%(_*[0-9])*)?>|<0[xX]_*[0-9a-fA-F]%(_*[0-9a-fA-F])*_*[pP][-+]?[0-9]%(_*[0-9])*>"

" Keyword definitions. These must be patterns instead of keywords
" because otherwise they would match as keywords at the start of a
" "literate" comment (see lhs.vim).
syn match hsModule		"\<module\>"
syn match hsImport		"\<import\>.*"he=s+6 contains=hsImportMod,hsLineComment,hsBlockComment
syn match hsImportMod		contained "\<\(as\|qualified\|hiding\)\>"
syn match hsInfix		"\<\(infix\|infixl\|infixr\)\>"
syn match hsStructure		"\<\(class\|data\|deriving\|instance\|default\|where\)\>"
syn match hsTypedef		"\<\(type\|newtype\)\>"
syn match hsStatement		"\<\(do\|case\|of\|let\|in\)\>"
syn match hsConditional		"\<\(if\|then\|else\)\>"

" Not real keywords, but close.
if exists("hs_highlight_boolean")
  " Boolean constants from the standard prelude.
  syn match hsBoolean "\<\(True\|False\)\>"
endif
if exists("hs_highlight_types")
  " Primitive types from the standard prelude and libraries.
  syn match hsType "\<\(Int\|Integer\|Char\|Bool\|Float\|Double\|IO\|Void\|Addr\|Array\|String\)\>"
endif
if exists("hs_highlight_more_types")
  " Types from the standard prelude libraries.
  syn match hsType "\<\(Maybe\|Either\|Ratio\|Complex\|Ordering\|IOError\|IOResult\|ExitCode\)\>"
  syn match hsMaybe    "\<Nothing\>"
  syn match hsExitCode "\<\(ExitSuccess\)\>"
  syn match hsOrdering "\<\(GT\|LT\|EQ\)\>"
endif
if exists("hs_highlight_debug")
  " Debugging functions from the standard prelude.
  syn match hsDebug "\<\(undefined\|error\|trace\)\>"
endif


" Comments
syn match   hsLineComment      "---*\([^-!#$%&\*\+./<=>\?@\\^|~].*\)\?$"
syn region  hsBlockComment     start="{-"  end="-}" contains=hsBlockComment
syn region  hsPragma	       start="{-#" end="#-}"

" C Preprocessor directives. Shamelessly ripped from c.vim and trimmed
" First, see whether to flag directive-like lines or not
if (!exists("hs_allow_hash_operator"))
    syn match	cError		display "^\s*\(%:\|#\).*$"
endif
" Accept %: for # (C99)
syn region	cPreCondit	start="^\s*\(%:\|#\)\s*\(if\|ifdef\|ifndef\|elif\)\>" skip="\\$" end="$" end="//"me=s-1 contains=cComment,cCppString,cCommentError
syn match	cPreCondit	display "^\s*\(%:\|#\)\s*\(else\|endif\)\>"
syn region	cCppOut		start="^\s*\(%:\|#\)\s*if\s\+0\+\>" end=".\@=\|$" contains=cCppOut2
syn region	cCppOut2	contained start="0" end="^\s*\(%:\|#\)\s*\(endif\>\|else\>\|elif\>\)" contains=cCppSkip
syn region	cCppSkip	contained start="^\s*\(%:\|#\)\s*\(if\>\|ifdef\>\|ifndef\>\)" skip="\\$" end="^\s*\(%:\|#\)\s*endif\>" contains=cCppSkip
syn region	cIncluded	display contained start=+"+ skip=+\\\\\|\\"+ end=+"+
syn match	cIncluded	display contained "<[^>]*>"
syn match	cInclude	display "^\s*\(%:\|#\)\s*include\>\s*["<]" contains=cIncluded
syn cluster	cPreProcGroup	contains=cPreCondit,cIncluded,cInclude,cDefine,cCppOut,cCppOut2,cCppSkip,cCommentStartError
syn region	cDefine		matchgroup=cPreCondit start="^\s*\(%:\|#\)\s*\(define\|undef\)\>" skip="\\$" end="$"
syn region	cPreProc	matchgroup=cPreCondit start="^\s*\(%:\|#\)\s*\(pragma\>\|line\>\|warning\>\|warn\>\|error\>\)" skip="\\$" end="$" keepend

syn region	cComment	matchgroup=cCommentStart start="/\*" end="\*/" contains=cCommentStartError,cSpaceError contained
syntax match	cCommentError	display "\*/" contained
syntax match	cCommentStartError display "/\*"me=e-1 contained
syn region	cCppString	start=+L\="+ skip=+\\\\\|\\"\|\\$+ excludenl end=+"+ end='$' contains=cSpecial contained

" Define the default highlighting.
" Only when an item doesn't have highlighting yet

hi def link hsModule			  hsStructure
hi def link hsImport			  Include
hi def link hsImportMod			  hsImport
hi def link hsInfix			  PreProc
hi def link hsStructure			  Structure
hi def link hsStatement			  Statement
hi def link hsConditional			  Conditional
hi def link hsSpecialChar			  SpecialChar
hi def link hsTypedef			  Typedef
hi def link hsVarSym			  hsOperator
hi def link hsConSym			  hsOperator
hi def link hsOperator			  Operator
if exists("hs_highlight_delimiters")
" Some people find this highlighting distracting.
hi def link hsDelimiter			  Delimiter
endif
hi def link hsSpecialCharError		  Error
hi def link hsString			  String
hi def link hsCharacter			  Character
hi def link hsNumber			  Number
hi def link hsFloat			  Float
hi def link hsConditional			  Conditional
hi def link hsLiterateComment		  hsComment
hi def link hsBlockComment		  hsComment
hi def link hsLineComment			  hsComment
hi def link hsComment			  Comment
hi def link hsPragma			  SpecialComment
hi def link hsBoolean			  Boolean
hi def link hsType			  Type
hi def link hsMaybe			  hsEnumConst
hi def link hsOrdering			  hsEnumConst
hi def link hsEnumConst			  Constant
hi def link hsDebug			  Debug

hi def link cCppString		hsString
hi def link cCommentStart		hsComment
hi def link cCommentError		hsError
hi def link cCommentStartError	hsError
hi def link cInclude		Include
hi def link cPreProc		PreProc
hi def link cDefine		Macro
hi def link cIncluded		hsString
hi def link cError			Error
hi def link cPreCondit		PreCondit
hi def link cComment		Comment
hi def link cCppSkip		cCppOut
hi def link cCppOut2		cCppOut
hi def link cCppOut		Comment


let b:current_syntax = "haskell"

" Options for vi: ts=8 sw=2 sts=2 nowrap noexpandtab ft=vim