Fix checking for equality of blank nodes, variables, and functions co…

…ntaining either in parser.

Fixes #46.

lib/sparql/grammar/parser11.rb

@@ -1610,7 +1610,7 @@ class Parser
       if data[:_Compare_Numeric]
         add_prod_datum(:Expression, SPARQL::Algebra::Expression.for(data[:_Compare_Numeric].insert(1, *data[:Expression])))
       elsif data[:in]
-        expr = (data[:Expression] + data[:in]).reject {|v| v.equal?(RDF.nil)}
+        expr = (data[:Expression] + data[:in]).reject {|v| v.eql?(RDF.nil)}
         add_prod_datum(:Expression, SPARQL::Algebra::Expression.for(expr.unshift(:in)))
       elsif data[:notin]
         expr = (data[:Expression] + data[:notin]).reject {|v| v.equal?(RDF.nil)}
@@ -2452,7 +2452,7 @@ def merge_modifiers(data)
 
           # Replace aggregates in expr as above
           expr.replace_aggregate! do |function|
-            if avf = aggregates.detect {|(_, f)| f == function}
+            if avf = aggregates.detect {|(_, f)| f.equal?(function)}
               avf.first
             else
               # Allocate a temporary variable for this function, and retain the mapping for outside the group

spec/grammar/misc_spec.rb

@@ -124,6 +124,22 @@
            (bgp (triple ??0 <http://example/c> <http://example/d>))
         )}
       },
+      "issue 46" => {
+        query: %(
+          PREFIX ex: <http://example.org/>
+
+          SELECT ?ev (MIN(?a) as ?a_min) (MIN(?b) as ?b_min)
+          WHERE {?ev ex:a ?a ; ex:b ?b . }
+          GROUP BY ?ev
+        ),
+        sse: %{(project (?ev ?a_min ?b_min)
+                (extend ((?a_min ??.0) (?b_min ??.1))
+                 (group (?ev) ((??.0 (min ?a)) (??.1 (min ?b)))
+                  (bgp
+                   (triple ?ev <http://example.org/a> ?a)
+                   (triple ?ev <http://example.org/b> ?b)))))
+        }
+      }
     }.each do |test, options|
       it "parses #{test}" do
         expect(options[:query]).to generate(options[:sse], logger: logger)