Add Augeas lexer (rouge-ruby#1521)

This commit adds a lexer for Augeas.

Co-authored-by: Michael Camilleri <mike@inqk.net>

lib/rouge/demos/augeas

@@ -0,0 +1,16 @@
+(*
+  This is a comment
+*)
+module Foo =
+autoload xfm
+
+let a = b | c . d
+
+let lns = a*
+
+let filter = incl "/path/to/file"
+           . incl "/path/to/other_file"
+           . Util.stdexcl
+
+(* xmf is the transform *)
+let xmf = transform lns filter

lib/rouge/lexers/augeas.rb

@@ -0,0 +1,93 @@
+# -*- coding: utf-8 -*- #
+# frozen_string_literal: true
+
+module Rouge
+  module Lexers
+    class Augeas < RegexLexer
+      title "Augeas"
+      desc "The Augeas programming language (augeas.net)"
+
+      tag 'augeas'
+      aliases 'aug'
+      filenames '*.aug'
+      mimetypes 'text/x-augeas'
+
+      def self.reserved
+        @reserved ||= Set.new %w(
+          _ let del store value counter seq key label autoload incl excl
+          transform test get put in after set clear insa insb print_string
+          print_regexp print_endline print_tree lens_ctype lens_atype
+          lens_ktype lens_vtype lens_format_atype regexp_match
+        )
+      end
+
+      state :basic do
+        rule %r/\s+/m, Text
+        rule %r/\(\*/, Comment::Multiline, :comment
+      end
+
+      state :comment do
+        rule %r/\*\)/, Comment::Multiline, :pop!
+        rule %r/\(\*/, Comment::Multiline, :comment
+        rule %r/[^*)]+/, Comment::Multiline
+        rule %r/[*)]/, Comment::Multiline
+      end
+
+      state :root do
+        mixin :basic
+
+        rule %r/(:)(\w\w*)/ do
+          groups Punctuation, Keyword::Type
+        end
+
+        rule %r/\w[\w']*/ do |m|
+          name = m[0]
+          if name == "module"
+            token Keyword::Reserved
+            push :module
+          elsif self.class.reserved.include? name
+            token Keyword::Reserved
+          elsif name =~ /\A[A-Z]/
+            token Keyword::Namespace
+          else
+            token Name
+          end
+        end
+
+        rule %r/"/, Str, :string
+        rule %r/\//, Str, :regexp
+
+        rule %r([-*+.=?\|]+), Operator
+        rule %r/[\[\](){}:;]/, Punctuation
+      end
+
+      state :module do
+        rule %r/\s+/, Text
+        rule %r/[A-Z][a-zA-Z0-9_.]*/, Name::Namespace, :pop!
+      end
+
+      state :regexp do
+        rule %r/\//, Str::Regex, :pop!
+        rule %r/[^\\\/]+/, Str::Regex
+        rule %r/\\[\\\/]/, Str::Regex
+        rule %r/\\/, Str::Regex
+      end
+
+      state :string do
+        rule %r/"/, Str, :pop!
+        rule %r/\\/, Str::Escape, :escape
+        rule %r/[^\\"]+/, Str
+      end
+
+      state :escape do
+        rule %r/[abfnrtv"'&\\]/, Str::Escape, :pop!
+        rule %r/\^[\]\[A-Z@\^_]/, Str::Escape, :pop!
+        rule %r/o[0-7]+/i, Str::Escape, :pop!
+        rule %r/x[\da-f]+/i, Str::Escape, :pop!
+        rule %r/\d+/, Str::Escape, :pop!
+        rule %r/\s+/, Str::Escape, :pop!
+        rule %r/./, Str, :pop!
+      end
+    end
+  end
+end

spec/lexers/augeas_spec.rb

@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*- #
+# frozen_string_literal: true
+
+describe Rouge::Lexers::Augeas do
+  let(:subject) { Rouge::Lexers::Augeas.new }
+
+  describe 'guessing' do
+    include Support::Guessing
+
+    it 'guesses by filename' do
+      assert_guess :filename => 'foo.aug'
+    end
+
+    it 'guess by mimetype' do
+      assert_guess :mimetype => 'text/x-augeas'
+    end
+  end
+end
+

spec/visual/samples/augeas

@@ -0,0 +1,32 @@
+(*
+Multiline
+Comment
+*)
+
+module Example =
+  autoload xfm
+
+let eol      = Util.eol
+let sep_spc  = Sep.space
+let sep_cont = Sep.cl_or_space
+
+let sep_cont_opt_build (sep:string) =
+   del (Rx.cl_or_opt_space . sep . Rx.cl_or_opt_space) (" " . sep . " ")
+
+let negate_or_value (key:lens) (value:lens) =
+  [ del_negate . (negate_node . key | key . value) ]
+
+let del_negate = del /(!!)*/ ""
+
+let sto_to_com_cmnd = del_negate . negate_node? . (
+      let alias = Rx.word - /(NO)?(PASSWD|EXEC|SETENV)/
+     in let non_alias = /[\/a-z]([^,:#()\n\\]|\\\\[=:,\\])*[^,=:#() \t\n\\]|[^,=:#() \t\n\\]/
+   in store (alias | non_alias))
+
+let filter = (incl "/etc/sudoers")
+    . (incl "/usr/local/etc/sudoers")
+    . (incl "/etc/sudoers.d/*")
+    . (incl "/usr/local/etc/sudoers.d/*")
+    . (incl "/opt/csw/etc/sudoers")
+    . (incl "/etc/opt/csw/sudoers")
+    . Util.stdexcl