proof of concept removing C parts of Json::Generator::State from Ruby json gem

.diff

diff --git a/java/src/json/ext/GeneratorState.java b/java/src/json/ext/GeneratorState.java
index 909f1a5..e3000b8 100644
--- a/java/src/json/ext/GeneratorState.java
+++ b/java/src/json/ext/GeneratorState.java
@@ -158,41 +158,6 @@ public class GeneratorState extends RubyObject {
         return (GeneratorState)info.getSafeStatePrototype(context).dup();
     }
 
-    /**
-     * <code>State#initialize(opts = {})</code>
-     *
-     * Instantiates a new <code>State</code> object, configured by <code>opts</code>.
-     *
-     * <code>opts</code> can have the following keys:
-     *
-     * <dl>
-     * <dt><code>:indent</code>
-     * <dd>a {@link RubyString String} used to indent levels (default: <code>""</code>)
-     * <dt><code>:space</code>
-     * <dd>a String that is put after a <code>':'</code> or <code>','</code>
-     * delimiter (default: <code>""</code>)
-     * <dt><code>:space_before</code>
-     * <dd>a String that is put before a <code>":"</code> pair delimiter
-     * (default: <code>""</code>)
-     * <dt><code>:object_nl</code>
-     * <dd>a String that is put at the end of a JSON object (default: <code>""</code>)
-     * <dt><code>:array_nl</code>
-     * <dd>a String that is put at the end of a JSON array (default: <code>""</code>)
-     * <dt><code>:allow_nan</code>
-     * <dd><code>true</code> if <code>NaN</code>, <code>Infinity</code>, and
-     * <code>-Infinity</code> should be generated, otherwise an exception is
-     * thrown if these values are encountered.
-     * This options defaults to <code>false</code>.
-     * <dt><code>:script_safe</code>
-     * <dd>set to <code>true</code> if U+2028, U+2029 and forward slashes should be escaped
-     * in the json output to make it safe to include in a JavaScript tag (default: <code>false</code>)
-     */
-    @JRubyMethod(optional=1, visibility=Visibility.PRIVATE)
-    public IRubyObject initialize(ThreadContext context, IRubyObject[] args) {
-        configure(context, args.length > 0 ? args[0] : null);
-        return this;
-    }
-
     @JRubyMethod
     public IRubyObject initialize_copy(ThreadContext context, IRubyObject vOrig) {
         Ruby runtime = context.getRuntime();
@@ -239,29 +204,6 @@ public class GeneratorState extends RubyObject {
         return false;
     }
 
-    @JRubyMethod(name="[]", required=1)
-    public IRubyObject op_aref(ThreadContext context, IRubyObject vName) {
-        String name = vName.asJavaString();
-        if (getMetaClass().isMethodBound(name, true)) {
-            return send(context, vName, Block.NULL_BLOCK);
-        } else {
-            IRubyObject value = getInstanceVariables().getInstanceVariable("@" + name);
-            return value == null ? context.nil : value;
-        }
-    }
-
-    @JRubyMethod(name="[]=", required=2)
-    public IRubyObject op_aset(ThreadContext context, IRubyObject vName, IRubyObject value) {
-        String name = vName.asJavaString();
-        String nameWriter = name + "=";
-        if (getMetaClass().isMethodBound(nameWriter, true)) {
-            return send(context, context.getRuntime().newString(nameWriter), value, Block.NULL_BLOCK);
-        } else {
-            getInstanceVariables().setInstanceVariable("@" + name, value);
-        }
-        return context.getRuntime().getNil();
-    }
-
     public ByteList getIndent() {
         return indent;
     }
@@ -458,78 +400,6 @@ public class GeneratorState extends RubyObject {
         return str.getByteList().dup();
     }
 
-    /**
-     * <code>State#configure(opts)</code>
-     *
-     * <p>Configures this State instance with the {@link RubyHash Hash}
-     * <code>opts</code>, and returns itself.
-     * @param vOpts The options hash
-     * @return The receiver
-     */
-  @JRubyMethod(alias = "merge")
-    public IRubyObject configure(ThreadContext context, IRubyObject vOpts) {
-        OptionsReader opts = new OptionsReader(context, vOpts);
-
-        ByteList indent = opts.getString("indent");
-        if (indent != null) this.indent = indent;
-
-        ByteList space = opts.getString("space");
-        if (space != null) this.space = space;
-
-        ByteList spaceBefore = opts.getString("space_before");
-        if (spaceBefore != null) this.spaceBefore = spaceBefore;
-
-        ByteList arrayNl = opts.getString("array_nl");
-        if (arrayNl != null) this.arrayNl = arrayNl;
-
-        ByteList objectNl = opts.getString("object_nl");
-        if (objectNl != null) this.objectNl = objectNl;
-
-        maxNesting = opts.getInt("max_nesting", DEFAULT_MAX_NESTING);
-        allowNaN   = opts.getBool("allow_nan",  DEFAULT_ALLOW_NAN);
-        asciiOnly  = opts.getBool("ascii_only", DEFAULT_ASCII_ONLY);
-        scriptSafe = opts.getBool("script_safe", DEFAULT_SCRIPT_SAFE);
-        if (!scriptSafe) {
-            scriptSafe = opts.getBool("escape_slash", DEFAULT_SCRIPT_SAFE);
-        }
-        strict = opts.getBool("strict", DEFAULT_STRICT);
-        bufferInitialLength = opts.getInt("buffer_initial_length", DEFAULT_BUFFER_INITIAL_LENGTH);
-
-        depth = opts.getInt("depth", 0);
-
-        return this;
-    }
-
-    /**
-     * <code>State#to_h()</code>
-     *
-     * <p>Returns the configuration instance variables as a hash, that can be
-     * passed to the configure method.
-     * @return the hash
-     */
-    @JRubyMethod(alias = "to_hash")
-    public RubyHash to_h(ThreadContext context) {
-        Ruby runtime = context.getRuntime();
-        RubyHash result = RubyHash.newHash(runtime);
-
-        result.op_aset(context, runtime.newSymbol("indent"), indent_get(context));
-        result.op_aset(context, runtime.newSymbol("space"), space_get(context));
-        result.op_aset(context, runtime.newSymbol("space_before"), space_before_get(context));
-        result.op_aset(context, runtime.newSymbol("object_nl"), object_nl_get(context));
-        result.op_aset(context, runtime.newSymbol("array_nl"), array_nl_get(context));
-        result.op_aset(context, runtime.newSymbol("allow_nan"), allow_nan_p(context));
-        result.op_aset(context, runtime.newSymbol("ascii_only"), ascii_only_p(context));
-        result.op_aset(context, runtime.newSymbol("max_nesting"), max_nesting_get(context));
-        result.op_aset(context, runtime.newSymbol("script_safe"), script_safe_get(context));
-        result.op_aset(context, runtime.newSymbol("strict"), strict_get(context));
-        result.op_aset(context, runtime.newSymbol("depth"), depth_get(context));
-        result.op_aset(context, runtime.newSymbol("buffer_initial_length"), buffer_initial_length_get(context));
-        for (String name: getInstanceVariableNameList()) {
-            result.op_aset(context, runtime.newSymbol(name.substring(1)), getInstanceVariables().getInstanceVariable(name));
-        }
-        return result;
-    }
-
     public int increaseDepth() {
         depth++;
         checkMaxNesting();
diff --git a/lib/json/pure/generator.rb b/lib/json/pure/generator.rb
index 75b0a40..4a8edca 100644
--- a/lib/json/pure/generator.rb
+++ b/lib/json/pure/generator.rb
@@ -114,7 +114,8 @@ module JSON
             SAFE_STATE_PROTOTYPE.dup
           end
         end
-
+        # call-seq: new(opts = {})
+        #
         # Instantiates a new State object, configured by _opts_.
         #
         # _opts_ can have the following keys:
@@ -124,26 +125,17 @@ module JSON
         # * *space_before*: a string that is put before a : pair delimiter (default: ''),
         # * *object_nl*: a string that is put at the end of a JSON object (default: ''),
         # * *array_nl*: a string that is put at the end of a JSON array (default: ''),
-        # * *script_safe*: true if U+2028, U+2029 and forward slash (/) should be escaped
-        #   as to make the JSON object safe to interpolate in a script tag (default: false).
-        # * *check_circular*: is deprecated now, use the :max_nesting option instead,
-        # * *max_nesting*: sets the maximum level of data structure nesting in
-        #   the generated JSON, max_nesting = 0 if no maximum should be checked.
         # * *allow_nan*: true if NaN, Infinity, and -Infinity should be
         #   generated, otherwise an exception is thrown, if these values are
         #   encountered. This options defaults to false.
-        def initialize(opts = {})
-          @indent                = ''
-          @space                 = ''
-          @space_before          = ''
-          @object_nl             = ''
-          @array_nl              = ''
-          @allow_nan             = false
-          @ascii_only            = false
-          @script_safe          = false
-          @strict                = false
-          @buffer_initial_length = 1024
-          configure opts
+        # * *ascii_only*: true if only ASCII characters should be generated. This
+        #   option defaults to false.
+        # * *buffer_initial_length*: sets the initial length of the generator's
+        #   internal buffer.
+        def initialize(opts = nil)
+          if opts && !opts.empty?
+            configure(opts)
+          end
         end
 
         # This string is used to indent levels in the JSON text.
@@ -226,64 +218,84 @@ module JSON
           @strict
         end
 
+        # call-seq: configure(opts)
+        #
         # Configure this State instance with the Hash _opts_, and return
         # itself.
         def configure(opts)
-          if opts.respond_to?(:to_hash)
-            opts = opts.to_hash
-          elsif opts.respond_to?(:to_h)
-            opts = opts.to_h
-          else
-            raise TypeError, "can't convert #{opts.class} into Hash"
-          end
-          opts.each do |key, value|
-            instance_variable_set "@#{key}", value
+          unless opts.is_a?(Hash)
+            if opts.respond_to?(:to_hash)
+              opts = opts.to_hash
+            elsif opts.respond_to?(:to_h)
+              opts = opts.to_h
+            else
+              raise TypeError, "can't convert #{opts.class} into Hash"
+            end
           end
 
-          # NOTE: If adding new instance variables here, check whether #generate should check them for #generate_json
-          @indent                = opts[:indent] if opts.key?(:indent)
-          @space                 = opts[:space] if opts.key?(:space)
-          @space_before          = opts[:space_before] if opts.key?(:space_before)
-          @object_nl             = opts[:object_nl] if opts.key?(:object_nl)
-          @array_nl              = opts[:array_nl] if opts.key?(:array_nl)
-          @allow_nan             = !!opts[:allow_nan] if opts.key?(:allow_nan)
-          @ascii_only            = opts[:ascii_only] if opts.key?(:ascii_only)
-          @depth                 = opts[:depth] || 0
-          @buffer_initial_length ||= opts[:buffer_initial_length]
-
-          @script_safe = if opts.key?(:script_safe)
-            !!opts[:script_safe]
-          elsif opts.key?(:escape_slash)
-            !!opts[:escape_slash]
-          else
-            false
+          opts.each do |key, value|
+            case key
+            when :indent
+              self.indent = value
+            when :space
+              self.space = value
+            when :space_before
+              self.space_before = value
+            when :array_nl
+              self.array_nl = value
+            when :object_nl
+              self.object_nl = value
+            when :max_nesting
+              self.max_nesting = value || 0
+            when :depth
+              self.depth = value
+            when :buffer_initial_length
+              self.buffer_initial_length = value
+            when :allow_nan
+              self.allow_nan = value
+            when :ascii_only
+              self.ascii_only = value
+            when :script_safe, :escape_slash
+              self.script_safe = value
+            when :strict
+              self.strict = value
+            end
           end
 
-          @strict                = !!opts[:strict] if opts.key?(:strict)
-
-          if !opts.key?(:max_nesting) # defaults to 100
-            @max_nesting = 100
-          elsif opts[:max_nesting]
-            @max_nesting = opts[:max_nesting]
-          else
-            @max_nesting = 0
-          end
           self
         end
-        alias merge configure
 
+        alias_method :merge, :configure
+
+        # call-seq: to_h
+        #
         # Returns the configuration instance variables as a hash, that can be
         # passed to the configure method.
         def to_h
-          result = {}
+          result = {
+            indent: indent,
+            space: space,
+            space_before: space_before,
+            object_nl: object_nl,
+            array_nl: array_nl,
+            allow_nan: allow_nan?,
+            ascii_only: ascii_only?,
+            max_nesting: max_nesting,
+            script_safe: script_safe?,
+            strict: strict?,
+            depth: depth,
+            buffer_initial_length: buffer_initial_length,
+          }
+
           instance_variables.each do |iv|
             iv = iv.to_s[1..-1]
             result[iv.to_sym] = self[iv]
           end
+
           result
         end
 
-        alias to_hash to_h
+        alias_method :to_hash, :to_h
 
         # Generates a valid JSON document from object +obj+ and
         # returns the result. If no valid JSON document can be
@@ -354,7 +366,9 @@ module JSON
           end
         end
 
-        # Return the value returned by method +name+.
+        # call-seq: [](name)
+        #
+        # Returns the value returned by method +name+.
         def [](name)
           if respond_to?(name)
             __send__(name)
@@ -364,6 +378,9 @@ module JSON
           end
         end
 
+        # call-seq: []=(name, value)
+        #
+        # Sets the attribute name to value.
         def []=(name, value)
           if respond_to?(name_writer = "#{name}=")
             __send__ name_writer, value