Cloned and renamed the OCaml files

Cloned and renamed the OCaml files for a start of the FSharp lexer

lib/rouge/demos/fsharp

@@ -0,0 +1,12 @@
+(* Binary tree with leaves car­rying an integer. *)
+type tree = Leaf of int | Node of tree * tree
+
+let rec exists_leaf test tree =
+  match tree with
+  | Leaf v -> test v
+  | Node (left, right) ->
+      exists_leaf test left
+      || exists_leaf test right
+
+let has_even_leaf tree =
+  exists_leaf (fun n -> n mod 2 = 0) tree

lib/rouge/lexers/fsharp.rb

@@ -0,0 +1,111 @@
+# -*- coding: utf-8 -*- #
+
+module Rouge
+  module Lexers
+    class FSharp < RegexLexer
+      title "FSharp"
+      desc 'F# (fsharp.net)'
+      tag 'fsharp'
+      filenames '*.fs', '*.fsx'
+      mimetypes 'application/fsharp-script', 'text/x-fsharp', 'text/x-fsi'
+
+      def self.keywords
+        @keywords ||= Set.new %w(
+          as assert begin class constraint do done downto else end
+          exception external false for fun function functor if in include
+          inherit initializer lazy let match method module mutable new
+          object of open private raise rec sig struct then to true try
+          type value val virtual when while with
+        )
+      end
+
+      def self.keyopts
+        @keyopts ||= Set.new %w(
+          != # & && ( ) * \+ , - -. -> . .. : :: := :> ; ;; < <- =
+          > >] >} ? ?? [ [< [> [| ] _ ` { {< | |] } ~
+        )
+      end
+
+      def self.word_operators
+        @word_operators ||= Set.new %w(and asr land lor lsl lxor mod or)
+      end
+
+      def self.primitives
+        @primitives ||= Set.new %w(unit int float bool string char list array)
+      end
+
+      operator = %r([\[\];,{}_()!$%&*+./:<=>?@^|~#-]+)
+      id = /[a-z][\w']*/i
+      upper_id = /[A-Z][\w']*/
+
+      state :root do
+        rule /\s+/m, Text
+        rule /false|true|[(][)]|\[\]/, Name::Builtin::Pseudo
+        rule /#{upper_id}(?=\s*[.])/, Name::Namespace, :dotted
+        rule upper_id, Name::Class
+        rule /[(][*](?![)])/, Comment, :comment
+        rule id do |m|
+          match = m[0]
+          if self.class.keywords.include? match
+            token Keyword
+          elsif self.class.word_operators.include? match
+            token Operator::Word
+          elsif self.class.primitives.include? match
+            token Keyword::Type
+          else
+            token Name
+          end
+        end
+
+        rule operator do |m|
+          match = m[0]
+          if self.class.keyopts.include? match
+            token Punctuation
+          else
+            token Operator
+          end
+        end
+
+        rule /-?\d[\d_]*(.[\d_]*)?(e[+-]?\d[\d_]*)/i, Num::Float
+        rule /0x\h[\h_]*/i, Num::Hex
+        rule /0o[0-7][0-7_]*/i, Num::Oct
+        rule /0b[01][01_]*/i, Num::Bin
+        rule /\d[\d_]*/, Num::Integer
+
+        rule /'(?:(\\[\\"'ntbr ])|(\\[0-9]{3})|(\\x\h{2}))'/, Str::Char
+        rule /'[.]'/, Str::Char
+        rule /'/, Keyword
+        rule /"/, Str::Double, :string
+        rule /[~?]#{id}/, Name::Variable
+      end
+
+      state :comment do
+        rule /[^(*)]+/, Comment
+        rule(/[(][*]/) { token Comment; push }
+        rule /[*][)]/, Comment, :pop!
+        rule /[(*)]/, Comment
+      end
+
+      state :string do
+        rule /[^\\"]+/, Str::Double
+        mixin :escape_sequence
+        rule /\\\n/, Str::Double
+        rule /"/, Str::Double, :pop!
+      end
+
+      state :escape_sequence do
+        rule /\\[\\"'ntbr]/, Str::Escape
+        rule /\\\d{3}/, Str::Escape
+        rule /\\x\h{2}/, Str::Escape
+      end
+
+      state :dotted do
+        rule /\s+/m, Text
+        rule /[.]/, Punctuation
+        rule /#{upper_id}(?=\s*[.])/, Name::Namespace
+        rule upper_id, Name::Class, :pop!
+        rule id, Name, :pop!
+      end
+    end
+  end
+end

spec/lexers/fsharp_spec.rb

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+# -*- coding: utf-8 -*- #
+
+describe Rouge::Lexers::FSharp do
+  let(:subject) { Rouge::Lexers::FSharp.new }
+
+  describe 'guessing' do
+    include Support::Guessing
+
+    it 'guesses by filename' do
+      assert_guess :filename => 'foo.fs'
+      assert_guess :filename => 'foo.fsx'
+    end
+
+    it 'guesses by mimetype' do
+      assert_guess :mimetype => 'application/fsharp-script'
+	  assert_guess :mimetype => 'text/x-fsharp'
+	  assert_guess :mimetype => 'text/x-fsi'
+    end
+  end
+end
+