Proposed changes for mandatory escapes for N-Triples/Quads canonicali…

…zation.

lib/rdf/ntriples/writer.rb

@@ -125,16 +125,19 @@ def self.escape_unicode(u, encoding)
     # @see    http://www.w3.org/TR/n-triples/
     def self.escape_ascii(u, encoding)
       case (u = u.ord)
-        when (0x00..0x07) then escape_utf16(u)
-        when (0x0A)       then "\\n"
-        when (0x0D)       then "\\r"
-        when (0x0E..0x1F) then escape_utf16(u)
-        when (0x22)       then "\\\""
-        when (0x5C)       then "\\\\"
-        when (0x7F)       then escape_utf16(u)
-        when (0x00..0x7F) then u.chr
-        else
-          raise ArgumentError.new("expected an ASCII character in (0x00..0x7F), but got 0x#{u.to_s(16)}")
+      when (0x08)       then "\\b"
+      when (0x09)       then "\\t"
+      when (0x0A)       then "\\n"
+      when (0x0C)       then "\\f"
+      when (0x0D)       then "\\r"
+      when (0x22)       then "\\\""
+      when (0x27)       then "\\'"
+      when (0x5C)       then "\\\\"
+      when (0x00..0x1F) then escape_utf16(u)
+      when (0x7F)       then escape_utf16(u)
+      when (0x00..0x7F) then u.chr
+      else
+        raise ArgumentError.new("expected an ASCII character in (0x00..0x7F), but got 0x#{u.to_s(16)}")
       end
     end
 

spec/ntriples_spec.rb

@@ -848,17 +848,17 @@
       # @see http://www.w3.org/TR/rdf-testcases/#ntrip_strings
       it "should correctly escape ASCII characters (#x0-#x7F)" do
         (0x00..0x07).each { |u| expect(writer.escape(u.chr, encoding)).to eq "\\u#{u.to_s(16).upcase.rjust(4, '0')}" }
-        expect(writer.escape(0x08.chr, encoding)).to eq "\b"
-        expect(writer.escape(0x09.chr, encoding)).to eq "\t"
+        expect(writer.escape(0x08.chr, encoding)).to eq "\\b"
+        expect(writer.escape(0x09.chr, encoding)).to eq "\\t"
         expect(writer.escape(0x0A.chr, encoding)).to eq "\\n"
-        expect(writer.escape(0x0B.chr, encoding)).to eq "\v"
-        expect(writer.escape(0x0C.chr, encoding)).to eq "\f"
+        expect(writer.escape(0x0B.chr, encoding)).to eq "\\u000B"
+        expect(writer.escape(0x0C.chr, encoding)).to eq "\\f"
         expect(writer.escape(0x0D.chr, encoding)).to eq "\\r"
         (0x0E..0x1F).each { |u| expect(writer.escape(u.chr, encoding)).to eq "\\u#{u.to_s(16).upcase.rjust(4, '0')}" }
         (0x20..0x21).each { |u| expect(writer.escape(u.chr, encoding)).to eq u.chr }
         expect(writer.escape(0x22.chr, encoding)).to eq "\\\""
         (0x23..0x26).each { |u| expect(writer.escape(u.chr, encoding)).to eq u.chr }
-        expect(writer.escape(0x27.chr, encoding)).to eq "'"
+        expect(writer.escape(0x27.chr, encoding)).to eq "\\'"
         (0x28..0x5B).each { |u| expect(writer.escape(u.chr, encoding)).to eq u.chr }
         expect(writer.escape(0x5C.chr, encoding)).to eq "\\\\"
         (0x5D..0x7E).each { |u| expect(writer.escape(u.chr, encoding)).to eq u.chr }
@@ -910,17 +910,17 @@
       # @see http://www.w3.org/TR/rdf-testcases/#ntrip_strings
       it "should correctly escape ASCII characters (#x0-#x7F)" do
         (0x00..0x07).each { |u| expect(writer.escape(u.chr, encoding)).to eq "\\u#{u.to_s(16).upcase.rjust(4, '0')}" }
-        expect(writer.escape(0x08.chr, encoding)).to eq "\b"
-        expect(writer.escape(0x09.chr, encoding)).to eq "\t"
+        expect(writer.escape(0x08.chr, encoding)).to eq "\\b"
+        expect(writer.escape(0x09.chr, encoding)).to eq "\\t"
         expect(writer.escape(0x0A.chr, encoding)).to eq "\\n"
-        expect(writer.escape(0x0B.chr, encoding)).to eq "\v"
-        expect(writer.escape(0x0C.chr, encoding)).to eq "\f"
+        expect(writer.escape(0x0B.chr, encoding)).to eq "\\u000B"
+        expect(writer.escape(0x0C.chr, encoding)).to eq "\\f"
         expect(writer.escape(0x0D.chr, encoding)).to eq "\\r"
         (0x0E..0x1F).each { |u| expect(writer.escape(u.chr, encoding)).to eq "\\u#{u.to_s(16).upcase.rjust(4, '0')}" }
         (0x20..0x21).each { |u| expect(writer.escape(u.chr, encoding)).to eq u.chr }
         expect(writer.escape(0x22.chr, encoding)).to eq "\\\""
         (0x23..0x26).each { |u| expect(writer.escape(u.chr, encoding)).to eq u.chr }
-        expect(writer.escape(0x27.chr, encoding)).to eq "'"
+        expect(writer.escape(0x27.chr, encoding)).to eq "\\'"
         (0x28..0x5B).each { |u| expect(writer.escape(u.chr, encoding)).to eq u.chr }
         expect(writer.escape(0x5C.chr, encoding)).to eq "\\\\"
         (0x5D..0x7E).each { |u| expect(writer.escape(u.chr, encoding)).to eq u.chr }