Add Elm (elm-lang.org) support (#1174)

* Add Elm (elm-lang.org) support

* Simplify patterns and fix a few things inherited from haskell

* Add example and minified file

* Clean up comment pattern, drop redundant groups, tabs for indents

components.js

@@ -197,6 +197,10 @@ var components = {
 			"title": "Elixir",
 			"owner": "Golmote"
 		},
+		"elm": {
+			"title": "Elm",
+			"owner": "zwilias"
+		},
 		"erlang": {
 			"title": "Erlang",
 			"owner": "Golmote"

components/prism-elm.js

@@ -0,0 +1,44 @@
+Prism.languages.elm = {
+	comment: /--.*|{-[\s\S]*?-}/,
+	char: {
+		pattern: /'(?:[^\\'\r\n]|\\(?:[abfnrtv\\']|\d+|x[0-9a-fA-F]+))'/,
+		greedy: true
+	},
+	string: [
+		{
+			// Multiline strings are wrapped in triple ". Quotes may appear unescaped.
+			pattern: /"""[\s\S]*?"""/,
+			greedy: true
+		},
+		{
+			pattern: /"(?:[^\\"\r\n]|\\(?:[abfnrtv\\"]|\d+|x[0-9a-fA-F]+))*"/,
+			greedy: true
+		}
+	],
+	import_statement: {
+		// The imported or hidden names are not included in this import
+		// statement. This is because we want to highlight those exactly like
+		// we do for the names in the program.
+		pattern: /^\s*import\s+[A-Z]\w*(?:\.[A-Z]\w*)*(?:\s+as\s+([A-Z]\w*)(?:\.[A-Z]\w*)*)?(?:\s+exposing\s+)?/m,
+		inside: {
+			keyword: /\b(?:import|as|exposing)\b/
+		}
+	},
+	keyword: /\b(?:alias|as|case|else|exposing|if|in|infixl|infixr|let|module|of|then|type)\b/,
+	// These are builtin variables only. Constructors are highlighted later as a constant.
+	builtin: /\b(?:abs|acos|always|asin|atan|atan2|ceiling|clamp|compare|cos|curry|degrees|e|flip|floor|fromPolar|identity|isInfinite|isNaN|logBase|max|min|negate|never|not|pi|radians|rem|round|sin|sqrt|tan|toFloat|toPolar|toString|truncate|turns|uncurry|xor)\b/,
+	// decimal integers and floating point numbers | hexadecimal integers
+	number: /\b(?:\d+(?:\.\d+)?(?:e[+-]?\d+)?|0x[0-9a-f]+)\b/i,
+	// Most of this is needed because of the meaning of a single '.'.
+	// If it stands alone freely, it is the function composition.
+	// It may also be a separator between a module name and an identifier => no
+	// operator. If it comes together with other special characters it is an
+	// operator too.
+	// Valid operator characters in 0.18: +-/*=.$<>:&|^?%#@~!
+	// Ref: https://groups.google.com/forum/#!msg/elm-dev/0AHSnDdkSkQ/E0SVU70JEQAJ
+	operator: /\s\.\s|[+\-/*=.$<>:&|^?%#@~!]{2,}|[+\-/*=$<>:&|^?%#@~!]/,
+	// In Elm, nearly everything is a variable, do not highlight these.
+	hvariable: /\b(?:[A-Z]\w*\.)*[a-z]\w*\b/,
+	constant: /\b(?:[A-Z]\w*\.)*[A-Z]\w*\b/,
+	punctuation: /[{}[\]|(),.:]/
+};

examples/prism-elm.html

@@ -0,0 +1,94 @@
+<h1>Elm</h1>
+<p>To user this language, use the class "language-elm".</p>
+
+<h2>Comments</h2>
+<pre><code>-- Single line comment
+{- Multi-line
+comment -}</code></pre>
+
+<h2>Strings and characters</h2>
+<pre><code>'a'
+'\n'
+'\x03'
+"foo \" bar"
+"""
+"multiline strings" are also
+supported!
+"""</code></pre>
+
+<h2>Full example</h2>
+<pre><code>module Main exposing (..)
+
+import Html exposing (Html)
+import Svg exposing (..)
+import Svg.Attributes exposing (..)
+import Time exposing (Time, second)
+
+
+main =
+    Html.program
+        { init = init
+        , view = view
+        , update = update
+        , subscriptions = subscriptions
+        }
+
+
+
+-- MODEL
+
+
+type alias Model =
+    Time
+
+
+init : ( Model, Cmd Msg )
+init =
+    ( 0, Cmd.none )
+
+
+
+-- UPDATE
+
+
+type Msg
+    = Tick Time
+
+
+update : Msg -> Model -> ( Model, Cmd Msg )
+update msg model =
+    case msg of
+        Tick newTime ->
+            ( newTime, Cmd.none )
+
+
+
+-- SUBSCRIPTIONS
+
+
+subscriptions : Model -> Sub Msg
+subscriptions model =
+    Time.every second (\time -> Tick time)
+
+
+
+-- VIEW
+
+
+view : Model -> Html Msg
+view model =
+    let
+        angle =
+            turns (Time.inMinutes model)
+
+        handX =
+            toString (50 + 40 * cos angle)
+
+        handY =
+            toString (50 + 40 * sin angle)
+    in
+    svg [ viewBox "0 0 100 100", width "300px" ]
+        [ circle [ cx "50", cy "50", r "45", fill "#0B79CE" ] []
+        , line [ x1 "50", y1 "50", x2 handX, y2 handY, stroke "#023963" ] []
+        ]
+</code></pre>

tests/languages/elm/builtin_feature.test

@@ -0,0 +1,25 @@
+abs acos always asin atan atan2
+ceiling clamp compare cos curry
+degrees e flip floor fromPolar
+identity isInfinite isNaN
+logBase max min negate never
+not pi radians rem round sin
+sqrt tan toFloat toPolar toString
+truncate turns uncurry xor
+
+----------------------------------------------------
+
+[
+	["builtin", "abs"], ["builtin", "acos"], ["builtin", "always"], ["builtin", "asin"], ["builtin", "atan"], ["builtin", "atan2"],
+	["builtin", "ceiling"], ["builtin", "clamp"], ["builtin", "compare"], ["builtin", "cos"], ["builtin", "curry"],
+	["builtin", "degrees"], ["builtin", "e"], ["builtin", "flip"], ["builtin", "floor"], ["builtin", "fromPolar"],
+	["builtin", "identity"], ["builtin", "isInfinite"], ["builtin", "isNaN"],
+	["builtin", "logBase"], ["builtin", "max"], ["builtin", "min"], ["builtin", "negate"], ["builtin", "never"],
+	["builtin", "not"], ["builtin", "pi"], ["builtin", "radians"], ["builtin", "rem"], ["builtin", "round"], ["builtin", "sin"],
+	["builtin", "sqrt"], ["builtin", "tan"], ["builtin", "toFloat"], ["builtin", "toPolar"], ["builtin", "toString"],
+	["builtin", "truncate"], ["builtin", "turns"], ["builtin", "uncurry"], ["builtin", "xor"]
+]
+
+----------------------------------------------------
+
+Checks for all builtin.

tests/languages/elm/char_feature.test

@@ -0,0 +1,19 @@
+'a'
+'\''
+'\n'
+'\23'
+'\xFE'
+
+----------------------------------------------------
+
+[
+	["char", "'a'"],
+	["char", "'\\''"],
+	["char", "'\\n'"],
+	["char", "'\\23'"],
+	["char", "'\\xFE'"]
+]
+
+----------------------------------------------------
+
+Checks for chars.

tests/languages/elm/comment_feature.test

@@ -0,0 +1,14 @@
+-- foo
+{- foo
+bar -}
+
+----------------------------------------------------
+
+[
+	["comment", "-- foo"],
+	["comment", "{- foo\r\nbar -}"]
+]
+
+----------------------------------------------------
+
+Checks for single-line and multi-line comments.

tests/languages/elm/constant_feature.test

@@ -0,0 +1,15 @@
+Foo
+Foo.Bar
+Baz.Foobar_42
+
+----------------------------------------------------
+
+[
+	["constant", "Foo"],
+	["constant", "Foo.Bar"],
+	["constant", "Baz.Foobar_42"]
+]
+
+----------------------------------------------------
+
+Checks for constants.

tests/languages/elm/hvariable_feature.test

@@ -0,0 +1,15 @@
+foo
+Foo.bar
+Baz.foobar_42
+
+----------------------------------------------------
+
+[
+	["hvariable", "foo"],
+	["hvariable", "Foo.bar"],
+	["hvariable", "Baz.foobar_42"]
+]
+
+----------------------------------------------------
+
+Checks for hvariables.

tests/languages/elm/import_statement_feature.test

@@ -0,0 +1,48 @@
+import Foo
+import Foo_42.Bar as Foobar
+import Foo.Bar as Foo.Baz
+import List exposing (map)
+import Json.Decode as Json exposing (Decoder)
+
+----------------------------------------------------
+
+[
+	["import_statement", [
+		["keyword", "import"],
+		" Foo"
+	]],
+	["import_statement", [
+		["keyword", "import"],
+		" Foo_42.Bar ",
+		["keyword", "as"],
+		" Foobar"
+	]],
+	["import_statement", [
+		["keyword", "import"],
+		" Foo.Bar ",
+		["keyword", "as"],
+		" Foo.Baz"
+	]],
+	["import_statement", [
+		["keyword", "import"],
+		" List ",
+		["keyword", "exposing"]
+	]],
+	["punctuation", "("],
+	["hvariable", "map"],
+	["punctuation", ")"],
+	["import_statement", [
+		["keyword", "import"],
+		" Json.Decode ",
+		["keyword", "as"],
+		" Json ",
+		["keyword", "exposing"]
+	]],
+	["punctuation", "("],
+	["constant", "Decoder"],
+	["punctuation", ")"]
+]
+
+----------------------------------------------------
+
+Checks for import statement.

tests/languages/elm/keyword_feature.test

@@ -0,0 +1,19 @@
+alias as case else
+exposing if in
+infixl infixr let
+module of then
+type
+
+----------------------------------------------------
+
+[
+	["keyword", "alias"], ["keyword", "as"], ["keyword", "case"], ["keyword", "else"],
+	["keyword", "exposing"], ["keyword", "if"], ["keyword", "in"],
+	["keyword", "infixl"], ["keyword", "infixr"], ["keyword", "let"],
+	["keyword", "module"], ["keyword", "of"], ["keyword", "then"],
+	["keyword", "type"]
+]
+
+----------------------------------------------------
+
+Checks for all keywords.

tests/languages/elm/number_feature.test

@@ -0,0 +1,21 @@
+42
+3.14159
+2E3
+1.2e-4
+0.9e+1
+0xBadFace
+
+----------------------------------------------------
+
+[
+	["number", "42"],
+	["number", "3.14159"],
+	["number", "2E3"],
+	["number", "1.2e-4"],
+	["number", "0.9e+1"],
+	["number", "0xBadFace"]
+]
+
+----------------------------------------------------
+
+Checks for decimal and hexadecimal numbers.

tests/languages/elm/operator_feature.test

@@ -0,0 +1,33 @@
+..
+reverse . sort
++ - * /
+^ ^^ **
+&& ||
+< <= == /=
+>= > |
+++ : !!
+<- ->
+= :: =>
+>> >>= >@>
+~ ! @
+
+----------------------------------------------------
+
+[
+	["operator", ".."],
+	["hvariable", "reverse"], ["operator", " . "], ["hvariable", "sort"],
+	["operator", "+"], ["operator", "-"], ["operator", "*"], ["operator", "/"],
+	["operator", "^"], ["operator", "^^"], ["operator", "**"],
+	["operator", "&&"], ["operator", "||"],
+	["operator", "<"], ["operator", "<="], ["operator", "=="], ["operator", "/="],
+	["operator", ">="], ["operator", ">"], ["operator", "|"],
+	["operator", "++"], ["operator", ":"], ["operator", "!!"],
+	["operator", "<-"], ["operator", "->"],
+	["operator", "="], ["operator", "::"], ["operator", "=>"],
+	["operator", ">>"], ["operator", ">>="], ["operator", ">@>"],
+	["operator", "~"], ["operator", "!"], ["operator", "@"]
+]
+
+----------------------------------------------------
+
+Checks for operators.

tests/languages/elm/string_feature.test

@@ -0,0 +1,21 @@
+""
+"regular string"
+"fo\"o"
+"""foo
+   bar"""
+"""foo -- comment
+   bar"""
+
+----------------------------------------------------
+
+[
+	["string", "\"\""],
+	["string", "\"regular string\""],
+	["string", "\"fo\\\"o\""],
+	["string", "\"\"\"foo\r\n   bar\"\"\""],
+	["string", "\"\"\"foo -- comment\r\n   bar\"\"\""]
+]
+
+----------------------------------------------------
+
+Checks for strings.