Tweaks to preloaded contexts.

README.md

@@ -242,11 +242,15 @@ Then, when performing something like expansion:
 
 
 ## Preloading contexts
-In many cases, for small documents, processing time can be dominated by loading and parsing remote contexts. In particular, a small schema.org example may need to download a large context and turn it into an internal representation, before the actual document can be expanded for processing. Using `JSON::LD::Context.add_preloaded`, an implementation can perform this loading up-front, and make it available to the processor.
+In many cases, for small documents, processing time can be dominated by loading and parsing remote contexts. In particular, a small schema.org example may need to download a large context and turn it into an internal representation, before the actual document can be expanded for processing. Using {JSON::LD::Context.add_preloaded}, an implementation can perform this loading up-front, and make it available to the processor.
 
     ctx = JSON::LD::Context.new().parse('http://schema.org/')
     JSON::LD::Context.add_preloaded('http://schema.org/', ctx)
 
+On lookup, URIs with an `https` prefix are normalized to `http`.
+
+A context may be serialized to Ruby to speed this process using `Context#to_rb`. When loaded, this generated file will add entries to the {JSON::LD::Context::PRELOADED}.
+
 ## RDF Reader and Writer
 {JSON::LD} also acts as a normal RDF reader and writer, using the standard RDF.rb reader/writer interfaces:
 

example-files/nicholas-arduino-bench.rb

@@ -1,6 +1,7 @@
 #!/usr/bin/env ruby
 require "bundler/setup"
 require 'json/ld'
+#require File.expand_path('../schema-context', __FILE__)
 require 'benchmark/ips'
 
 source = JSON.parse %({

example-files/schema-context.rb

@@ -1,6 +1,9 @@
+# -*- encoding: utf-8 -*-
+# frozen_string_literal: true
+# This file generated automatically from http://schema.org
 require 'json/ld'
 class JSON::LD::Context
-  PRELOADED["http://schema.org/"] = JSON::LD::Context.new(vocab: "http://schema.org/", term_definitions: {
+  add_preloaded("http://schema.org/", new(vocab: "http://schema.org/", term_definitions: {
     "type" => TermDefinition.new("type", id: "@type", simple: true),
     "id" => TermDefinition.new("id", id: "@id", simple: true),
     "schema" => TermDefinition.new("schema", id: "http://schema.org/", simple: true),
@@ -2112,5 +2115,5 @@ class JSON::LD::Context
     "worstRating" => TermDefinition.new("worstRating", id: "http://schema.org/worstRating"),
     "yearlyRevenue" => TermDefinition.new("yearlyRevenue", id: "http://schema.org/yearlyRevenue"),
     "yearsInOperation" => TermDefinition.new("yearsInOperation", id: "http://schema.org/yearsInOperation")
-  })
+}))
 end

lib/json/ld/context.rb

@@ -13,8 +13,12 @@ class Context
     PRELOADED = {}
 
     class << self
+      ##
+      # Add preloaded context
+      # @param [String, RDF::URI] url
+      # @param [Context] context
       def add_preloaded(url, context)
-        PRELOADED[url.to_sym] = context
+        PRELOADED[url.to_s.freeze] = context
       end
     end
 
@@ -268,14 +272,14 @@ def vocab=(value)
       @vocab = case value
       when /_:/
         value
-      when String
-        v = as_resource(value)
-        raise JsonLdError::InvalidVocabMapping, "@value must be an absolute IRI: #{value.inspect}" if v.uri? && v.relative? && @options[:validate]
+      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
       when nil
         nil
       else
-        raise JsonLdError::InvalidVocabMapping, "@value must be a string: #{value.inspect}"
+        raise JsonLdError::InvalidVocabMapping, "@vocab must be an absolute IRI: #{value.inspect}"
       end
     end
 
@@ -336,10 +340,10 @@ def parse(local_context, remote_contexts = [])
             context_no_base.base = nil
             context_no_base.context_base = context.to_s
 
-            if PRELOADED[context_canon.to_s.to_sym]
+            if PRELOADED[context_canon.to_s]
               # If we have a cached context, merge it into the current context (result) and use as the new context
               log_debug("parse") {"=> cached_context: #{context_canon.to_s.inspect}"}
-              context = context_no_base.merge!(PRELOADED[context_canon.to_s.to_sym])
+              context = context_no_base.merge!(PRELOADED[context_canon.to_s])
             else
 
               # Load context document, if it is a string
@@ -1196,11 +1200,14 @@ def to_rb
       term_defs = term_definitions.map do |term, td|
         "    " + term.inspect + " => " + td.to_rb
       end
-      defn << "term_definitions: {\n#{term_defs.join(",\n")  }\n}" unless term_defs.empty?
-      %(require 'json/ld'
+      defn << "term_definitions: {\n#{term_defs.join(",\n")  }\n  }" unless term_defs.empty?
+      %(# -*- encoding: utf-8 -*-
+      # frozen_string_literal: true
+      # This file generated automatically from #{context_base}
+      require 'json/ld'
       class JSON::LD::Context
       ).gsub(/^      /, '') +
-      "  PRELOADED[#{RDF::URI(context_base).canonicalize.to_s.inspect}] = Context.new(" + defn.join(", ")  + ")\nend\n"
+      "  add_preloaded(#{RDF::URI(context_base).canonicalize.to_s.inspect}, Context.new(" + defn.join(", ")  + "))\nend\n"
     end
 
     def inspect