Change to use "@vocab": "" semantics, and vocabulary expansion/compaction just as if the effective document base was specified as @vocab.

Author: gkellogg

lib/json/ld/context.rb

@@ -354,16 +354,16 @@ def version=(value)
     # @param [String] value must be an absolute IRI
     def vocab=(value)
       @vocab = case value
-      when /_:/, '@base'
+      when /_:/
         value
       when String, RDF::URI
-        v = as_resource(value.to_s)
-        raise JsonLdError::InvalidVocabMapping, "@vocab must be an absolute IRI: #{value.inspect}" if v.uri? && v.relative? && @options[:validate]
+        v = as_resource(value.to_s, base)
+        raise JsonLdError::InvalidVocabMapping, "@vocab must be an IRI: #{value.inspect}" if !v.valid? && @options[:validate]
         v
       when nil
         nil
       else
-        raise JsonLdError::InvalidVocabMapping, "@vocab must be an absolute IRI: #{value.inspect}"
+        raise JsonLdError::InvalidVocabMapping, "@vocab must be an IRI: #{value.inspect}"
       end
     end
 
@@ -1034,10 +1034,10 @@ def expand_iri(value, documentRelative: false, vocab: false, local_context: nil,
       end
       #log_debug("") {"=> #{result.inspect}"} unless quiet
 
-      result = if vocab && self.vocab && self.vocab != '@base'
+      result = if vocab && self.vocab
         # If vocab is true, and active context has a vocabulary mapping, return the result of concatenating the vocabulary mapping with value.
         self.vocab + value
-      elsif (documentRelative || self.vocab == '@base') && (base ||= self.base)
+      elsif (documentRelative || self.vocab == '') && (base ||= self.base)
         # Otherwise, if document relative is true, set value to the result of resolving value against the base IRI. Only the basic algorithm in section 5.2 of [RFC3986] is used; neither Syntax-Based Normalization nor Scheme-Based Normalization are performed. Characters additionally allowed in IRI references are treated in the same way that unreserved characters are treated in URI references, per section 6.5 of [RFC3987].
         value = RDF::URI(value)
         value.absolute? ? value : RDF::URI(base).join(value)
@@ -1221,7 +1221,7 @@ def compact_iri(iri, value: nil, vocab: nil, reverse: false, quiet: false, **opt
         return candidates.term_sort.first if !candidates.empty?
       end
 
-      if !vocab || self.vocab == '@base'
+      if !vocab
         # transform iri to a relative IRI using the document's base IRI
         iri = remove_base(iri)
         #log_debug("") {"=> relative iri: #{iri.inspect}"} unless quiet

spec/compact_spec.rb

@@ -2153,11 +2153,11 @@
             "ex:bar": "term"
           })
         },
-        "compacts using base if @vocab: @base" => {
+        "compacts using base if @vocab: relative" => {
           input: %({"http://example.org/foo/bar": "term"}),
-          context: %({"@base": "http://example.org/foo/", "@vocab": "@base"}),
+          context: %({"@base": "http://example.org/foo/", "@vocab": ""}),
           output: %({
-            "@context": {"@base": "http://example.org/foo/", "@vocab": "@base"},
+            "@context": {"@base": "http://example.org/foo/", "@vocab": ""},
             "bar": "term"
           })
         },

spec/context_spec.rb

@@ -859,11 +859,11 @@ def containers
           end
         end
 
-        context "set to @base" do
+        context "set to ''" do
           subject {
             context.parse({
               '@base' => 'http://base/base',
-              '@vocab' => '@base',
+              '@vocab' => '',
               'ex' => 'http://example.org/',
               '' => 'http://empty/',
               '_' => 'http://underscore/'
@@ -876,9 +876,9 @@ def containers
             "prefix:suffix" => ["ex:suffix",           RDF::URI("http://example.org/suffix")],
             "keyword" =>       ["@type",               "@type"],
             "empty" =>         [":suffix",             RDF::URI("http://empty/suffix")],
-            "unmapped" =>      ["foo",                 RDF::URI("http://base/foo")],
-            "relative" =>      ["foo/bar",             RDF::URI("http://base/foo/bar")],
-            "dotseg" =>        ["../foo/bar",          RDF::URI("http://base/foo/bar")],
+            "unmapped" =>      ["foo",                 RDF::URI("http://base/basefoo")],
+            "relative" =>      ["foo/bar",             RDF::URI("http://base/basefoo/bar")],
+            "dotseg" =>        ["../foo/bar",          RDF::URI("http://base/base../foo/bar")],
             "empty term" =>    ["",                    RDF::URI("http://empty/")],
             "another abs IRI"=>["ex://foo",            RDF::URI("ex://foo")],
             "absolute IRI looking like a curie" =>
@@ -971,9 +971,9 @@ def containers
           not_to produce("name", logger)
       end
 
-      context "with @vocab: @base" do
+      context "with @vocab: relative" do
         before(:each) {
-          subject.vocab = "@base"
+          subject.vocab = ""
           subject.base = 'http://base/base'
         }
 

spec/expand_spec.rb

@@ -177,7 +177,7 @@
         {
           "base": {
             input: %({
-              "@context": {"@vocab": "http:///vocab/"},
+              "@context": {"@vocab": "http://vocab/"},
               "http://a/b": "foo"
             }),
             output: %([{
@@ -216,11 +216,11 @@
         end
       end
 
-      context "with @vocab: @base" do
+      context "with @vocab: ''" do
         {
           "base": {
             input: %({
-              "@context": {"@vocab": "@base"},
+              "@context": {"@vocab": ""},
               "http://a/b": "foo"
             }),
             output: %([{
@@ -229,7 +229,7 @@
           },
           "relative": {
             input: %({
-              "@context": {"@vocab": "@base"},
+              "@context": {"@vocab": ""},
               "a/b": "foo"
             }),
             output: %([{
@@ -238,7 +238,7 @@
           },
           "hash": {
             input: %({
-              "@context": {"@vocab": "@base"},
+              "@context": {"@vocab": ""},
               "#a": "foo"
             }),
             output: %([{
@@ -247,18 +247,18 @@
           },
           "dotseg": {
             input: %({
-              "@context": {"@vocab": "@base"},
+              "@context": {"@vocab": ""},
               "../a": "foo"
             }),
             output: %([{
-              "http://example.org/a": [{"@value": "foo"}]
+              "http://example.org/../a": [{"@value": "foo"}]
             }])
           },
           "example": {
             input: %({
               "@context": {
                 "@base": "http://example/document",
-                "@vocab": "@base"
+                "@vocab": ""
               },
               "@id": "http://example.org/places#BrewEats",
               "@type": "#Restaurant",