From c68336ee61da877ded42fc7f041288d6466e24af Mon Sep 17 00:00:00 2001
From: Michael Camilleri <mike@inqk.net>
Date: Wed, 13 May 2020 02:21:47 +0900
Subject: [PATCH] Support the 'a' keyword in SPARQL lexer (#1493)

The case-sensitive keyword `a` is a valid keyword in SPARQL. At
present, the SPARQL lexer does not recognise it as such. This commit
fixes that error (the rule is similar to the one used in the Turtle lexer).
---
 lib/rouge/lexers/sparql.rb | 9 +++++----
 spec/visual/samples/sparql | 8 ++++++++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/lib/rouge/lexers/sparql.rb b/lib/rouge/lexers/sparql.rb
index 3bbe64b5bb..4a9c2a4831 100644
--- a/lib/rouge/lexers/sparql.rb
+++ b/lib/rouge/lexers/sparql.rb
@@ -35,12 +35,12 @@ def self.keywords
       state :root do
         rule %r(\s+)m, Text::Whitespace
         rule %r(#.*), Comment::Single
-        
+
         rule %r("""), Str::Double, :string_double_literal
         rule %r("), Str::Double, :string_double
         rule %r('''), Str::Single, :string_single_literal
         rule %r('), Str::Single, :string_single
-       
+
         rule %r([$?]\w+), Name::Variable
         rule %r((\w*:)(\w+)?) do |m|
           token Name::Namespace, m[1]
@@ -48,7 +48,8 @@ def self.keywords
         end
         rule %r(<[^>]*>), Name::Namespace
         rule %r(true|false)i, Keyword::Constant
-        
+        rule %r/a\b/, Keyword
+
         rule %r([A-Z]\w+\b)i do |m|
           if self.class.builtins.include? m[0].upcase
             token Name::Builtin
@@ -101,7 +102,7 @@ def self.keywords
         end
         mixin :string_single_common
       end
-      
+
       state :string_single_literal do
         rule %r(''') do
           token Str::Single
diff --git a/spec/visual/samples/sparql b/spec/visual/samples/sparql
index fbd97f69ab..fc75931a9f 100644
--- a/spec/visual/samples/sparql
+++ b/spec/visual/samples/sparql
@@ -52,3 +52,11 @@ false
 '''The librarian said, "Perhaps you would enjoy 'War and Peace'."'''
 """The librarian said, 'Perhaps you would enjoy "War and Peace".'"""
 "\u4444 and \U88888888"
+
+# `a` keyword
+PREFIX : <http://example.org/#>
+SELECT ?item ?itemLabel
+WHERE
+{
+    ?item a :Test .
+}