if exists('g:polyglot_disabled') && index(g:polyglot_disabled, 'elm') != -1
  finish
endif

" syntax highlighting for Elm (http://elm-lang.org/)

if exists('b:current_syntax')
  finish
endif

" Keywords
syn keyword elmConditional else if of then
syn keyword elmAlias alias
syn keyword elmTypedef contained type port
syn keyword elmImport exposing as import module where

" Operators
syn match elmOperator contained "\([-!#$%`&\*\+./<=>\?@\\^|~:]\|\<_\>\)"

" Types
syn match elmType "\<[A-Z][0-9A-Za-z_'-]*"
syn keyword elmNumberType number

" Delimiters
syn match elmDelimiter  "[,;]"
syn match elmBraces  "[()[\]{}]"

" Functions
syn match elmTupleFunction "\((,\+)\)"

" Comments
syn keyword elmTodo TODO FIXME XXX contained
syn match elmLineComment "--.*" contains=elmTodo,@spell
syn region elmComment matchgroup=elmComment start="{-|\=" end="-}" contains=elmTodo,elmComment,@spell fold

" Strings
syn match elmStringEscape "\\u[0-9a-fA-F]\{4}" contained
syn match elmStringEscape "\\[nrfvbt\\\"]" contained
syn region elmString start="\"" skip="\\\"" end="\"" contains=elmStringEscape,@spell
syn region elmTripleString start="\"\"\"" skip="\\\"" end="\"\"\"" contains=elmStringEscape,@spell
syn match elmChar "'[^'\\]'\|'\\.'\|'\\u[0-9a-fA-F]\{4}'"

" Numbers
syn match elmInt "-\?\<\d\+\>\|0[xX][0-9a-fA-F]\+\>"
syn match elmFloat "\(\<\d\+\.\d\+\>\)"

" Identifiers
syn match elmTopLevelDecl "^\s*[a-zA-Z][a-zA-z0-9_]*\('\)*\s\+:\(\r\n\|\r\|\n\|\s\)\+" contains=elmOperator

" Folding
syn region elmTopLevelTypedef start="type" end="\n\(\n\n\)\@=" contains=ALL fold
syn region elmTopLevelFunction start="^[a-zA-Z].\+\n[a-zA-Z].\+=" end="^\(\n\+\)\@=" contains=ALL fold
syn region elmCaseBlock matchgroup=elmCaseBlockDefinition start="^\z\(\s\+\)\<case\>" end="^\z1\@!\W\@=" end="\(\n\n\z1\@!\)\@=" end="\n\z1\@!\(\n\n\)\@=" contains=ALL fold
syn region elmCaseItemBlock start="^\z\(\s\+\).\+->$" end="^\z1\@!\W\@=" end="\(\n\n\z1\@!\)\@=" end="\(\n\z1\S\)\@=" contains=ALL fold
syn region elmLetBlock matchgroup=elmLetBlockDefinition start="\<let\>" end="\<in\>" contains=ALL fold

hi def link elmCaseBlockDefinition Conditional
hi def link elmCaseBlockItemDefinition Conditional
hi def link elmLetBlockDefinition TypeDef
hi def link elmTopLevelDecl Function
hi def link elmTupleFunction Normal
hi def link elmTodo Todo
hi def link elmComment Comment
hi def link elmLineComment Comment
hi def link elmString String
hi def link elmTripleString String
hi def link elmChar String
hi def link elmStringEscape Special
hi def link elmInt Number
hi def link elmFloat Float
hi def link elmDelimiter Delimiter
hi def link elmBraces Delimiter
hi def link elmTypedef TypeDef
hi def link elmImport Include
hi def link elmConditional Conditional
hi def link elmAlias Delimiter
hi def link elmOperator Operator
hi def link elmType Identifier
hi def link elmNumberType Identifier

syn sync minlines=500

let b:current_syntax = 'elm'