Const correctness and minor bugfixes all over the code.

dyaml/composer.d

@@ -135,9 +135,7 @@ final class Composer
             //Drop the DOCUMENT-END event.
             parser_.getEvent();
 
-            //Clear anchors.
+            clear(anchors_);
-            Node[Anchor] empty;
-            anchors_ = empty;
             return node;
         }
 

dyaml/dumper.d

@@ -157,6 +157,8 @@ struct Dumper
 
     public:
         @disable this();
+        @disable bool opEquals(ref Dumper);
+        @disable int opCmp(ref Dumper);
 
         /**
          * Construct a Dumper writing to a file.
@@ -165,7 +167,7 @@ struct Dumper
          *
          * Throws: YAMLException if the file can not be dumped to (e.g. cannot be opened).
          */
-        this(string filename)
+        this(in string filename)
         {
             name_ = filename;
             try{this(new File(filename, FileMode.OutNew));}
@@ -195,33 +197,33 @@ struct Dumper
         }
 
         ///Set stream _name. Used in debugging messages.
-        @property void name(string name)
+        @property void name(in string name)
         {
             name_ = name;
         }
 
         ///Specify custom Resolver to use.
-        void resolver(Resolver resolver)
+        @property void resolver(Resolver resolver)
         {
             clear(resolver_);
             resolver_ = resolver;
         }
 
         ///Specify custom Representer to use.
-        void representer(Representer representer)
+        @property void representer(Representer representer)
         {
             clear(representer_);
             representer_ = representer;
         }
 
         ///Write scalars in _canonical form?
-        void canonical(in bool canonical)
+        @property void canonical(in bool canonical)
         {
             canonical_ = canonical;
         }
 
         ///Set indentation width. 2 by default. Must not be zero.
-        void indent(in uint indent)
+        @property void indent(in uint indent)
         in
         {   
             assert(indent != 0, "Can't use zero YAML indent width");
@@ -232,37 +234,37 @@ struct Dumper
         }
 
         ///Set preferred text _width.
-        void textWidth(in uint width)
+        @property void textWidth(in uint width)
         {
             textWidth_ = width;
         }
 
         ///Set line break to use. Unix by default.
-        void lineBreak(in LineBreak lineBreak)
+        @property void lineBreak(in LineBreak lineBreak)
         {
             lineBreak_ = lineBreak;
         }
 
         ///Set character _encoding to use. UTF-8 by default.
-        void encoding(in Encoding encoding)
+        @property void encoding(in Encoding encoding)
         {
             encoding_ = encoding;
         }    
 
         ///Always explicitly write document start?
-        void explicitStart(in bool explicit)
+        @property void explicitStart(in bool explicit)
         {
             explicitStart_ = explicit;
         }
 
         ///Always explicitly write document end?
-        void explicitEnd(in bool explicit)
+        @property void explicitEnd(in bool explicit)
         {
             explicitEnd_ = explicit;
         }
 
         ///Specify YAML version string. "1.1" by default.
-        void YAMLVersion(in string YAMLVersion)
+        @property void YAMLVersion(in string YAMLVersion)
         {
             YAMLVersion_ = YAMLVersion;
         }
@@ -297,7 +299,7 @@ struct Dumper
          * dumper.dump(Node("foo"));
          * --------------------
          */
-        void tagDirectives(string[string] tags)
+        @property void tagDirectives(string[string] tags)
         {
             tagDirective[] t;
             foreach(handle, prefix; tags)

dyaml/emitter.d

@@ -148,8 +148,8 @@ struct Emitter
         ScalarStyle style_ = ScalarStyle.Invalid;
 
     public:
-        @disable int opCmp(ref Emitter e);
+        @disable int opCmp(ref Emitter);
-        @disable bool opEquals(ref Emitter e);
+        @disable bool opEquals(ref Emitter);
 
         /**
          * Construct an emitter.
@@ -159,7 +159,8 @@ struct Emitter
          *          indent    = Indentation width.
          *          lineBreak = Line break character/s.
          */
-        this(Stream stream, bool canonical, int indent, int width, LineBreak lineBreak)
+        this(Stream stream, in bool canonical, in int indent, in int width, 
+             in LineBreak lineBreak)
         in{assert(stream.writeable, "Can't emit YAML to a non-writable stream");}
         body
         {
@@ -226,7 +227,7 @@ struct Emitter
         }
 
         ///Write a string to the file/stream.
-        void writeString(string str)
+        void writeString(in string str)
         {
             try final switch(encoding_)
             {
@@ -329,7 +330,7 @@ struct Emitter
         }
 
         ///Expect nothing, throwing if we still have something.
-        void expectNothing()
+        void expectNothing() const
         {
             throw new Error("Expected nothing, but got " ~ event_.idString);
         }
@@ -684,7 +685,7 @@ struct Emitter
             }
 
             immutable event = events_.peek();
-            bool emptyScalar = event.id == EventID.Scalar && event.anchor.isNull() &&
+            const emptyScalar = event.id == EventID.Scalar && event.anchor.isNull() &&
                                 event.tag.isNull() && event.implicit && event.value == "";
             return emptyScalar;
         }
@@ -867,7 +868,7 @@ struct Emitter
         static void encodeChar(Writer)(ref Writer writer, in dchar c)
         {
             char[4] data;
-            auto bytes = encode(data, c);
+            const bytes = encode(data, c);
             //For each byte add string in format %AB , where AB are hex digits of the byte.
             foreach(const char b; data[0 .. bytes])
             {
@@ -1261,6 +1262,9 @@ struct ScalarWriter
     }
 
     private:
+        @disable int opCmp(ref Emitter);
+        @disable bool opEquals(ref Emitter);
+
         ///Used as "null" UTF-32 character.
         immutable dcharNone = dchar.max;
 
@@ -1286,7 +1290,7 @@ struct ScalarWriter
 
     public:
         ///Construct a ScalarWriter using emitter to output text.
-        this(ref Emitter emitter, string text, bool split = true)
+        this(ref Emitter emitter, string text, in bool split = true)
         {
             emitter_ = &emitter;
             text_ = text;
@@ -1562,7 +1566,7 @@ struct ScalarWriter
         }
 
         ///Determine hints (indicators) for block scalar.
-        size_t determineBlockHints(ref char[] hints, uint bestIndent)
+        size_t determineBlockHints(ref char[] hints, uint bestIndent) const
         {
             size_t hintsIdx = 0;
             if(text_.length == 0){return hintsIdx;}
@@ -1597,7 +1601,7 @@ struct ScalarWriter
         {
             char[4] hints;
             hints[0] = indicator;
-            auto hintsLength = 1 + determineBlockHints(hints[1 .. $], emitter_.bestIndent_);
+            const hintsLength = 1 + determineBlockHints(hints[1 .. $], emitter_.bestIndent_);
             emitter_.writeIndicator(cast(string)hints[0 .. hintsLength], true);
             if(hints.length > 0 && hints[$ - 1] == '+')
             {

dyaml/escapes.d

@@ -11,11 +11,11 @@ module dyaml.escapes;
 package:
 
 ///Translation table from YAML escapes to dchars.
-dchar[dchar] fromEscapes;
+immutable dchar[dchar] fromEscapes;
 ///Translation table from dchars to YAML escapes.
-dchar[dchar] toEscapes;
+immutable dchar[dchar] toEscapes;
 ///Translation table from prefixes of escaped hexadecimal format characters to their lengths.
-uint[dchar]  escapeHexCodes;
+immutable uint[dchar]  escapeHexCodes;
 
 
 static this()

dyaml/event.d

@@ -47,6 +47,8 @@ enum EventID : ubyte
  */
 struct Event
 {
+    @disable int opCmp(ref Event);
+
     ///Value of the event, if any.
     string value;
     ///Start position of the event in file/stream.
@@ -108,7 +110,7 @@ Event event(EventID id)(in Mark start, in Mark end, in Anchor anchor = Anchor())
  */
 Event collectionStartEvent(EventID id)(in Mark start, in Mark end, in Anchor anchor, 
                                        in Tag tag, in bool implicit, 
-                                       in CollectionStyle style)
+                                       in CollectionStyle style) pure
 {
     static assert(id == EventID.SequenceStart || id == EventID.SequenceEnd ||
                   id == EventID.MappingStart || id == EventID.MappingEnd);
@@ -123,7 +125,7 @@ Event collectionStartEvent(EventID id)(in Mark start, in Mark end, in Anchor anc
  *          end      = End position of the event in the file/stream.
  *          encoding = Encoding of the stream.
  */
-Event streamStartEvent(in Mark start, in Mark end, Encoding encoding) 
+Event streamStartEvent(in Mark start, in Mark end, in Encoding encoding) pure
 {
     return Event(null, start, end, Anchor(), Tag(), EventID.StreamStart, 
                  ScalarStyle.Invalid, false, false, TagDirectives(), encoding);
@@ -148,8 +150,8 @@ alias collectionStartEvent!(EventID.MappingStart) mappingStartEvent;
  *          YAMLVersion   = YAML version string of the document.
  *          tagDirectives = Tag directives of the document.
  */
-Event documentStartEvent(Mark start, Mark end, bool explicit, string YAMLVersion,
+Event documentStartEvent(in Mark start, in Mark end, bool explicit, string YAMLVersion,
-                         TagDirectives tagDirectives)
+                         in TagDirectives tagDirectives) pure
 {
     return Event(YAMLVersion, start, end, Anchor(), Tag(), EventID.DocumentStart, 
                  ScalarStyle.Invalid, explicit, false, tagDirectives);
@@ -162,7 +164,7 @@ Event documentStartEvent(Mark start, Mark end, bool explicit, string YAMLVersion
  *          end      = End position of the event in the file/stream.
  *          explicit = Is this an explicit document end?
  */
-Event documentEndEvent(Mark start, Mark end, bool explicit)
+Event documentEndEvent(in Mark start, in Mark end, bool explicit) pure
 {
     return Event(null, start, end, Anchor(), Tag(), EventID.DocumentEnd,
                  ScalarStyle.Invalid, explicit);
@@ -181,7 +183,7 @@ Event documentEndEvent(Mark start, Mark end, bool explicit)
  */
 Event scalarEvent(in Mark start, in Mark end, in Anchor anchor, in Tag tag, 
                   in Tuple!(bool, bool) implicit, in string value, 
-                  in ScalarStyle style = ScalarStyle.Invalid) 
+                  in ScalarStyle style = ScalarStyle.Invalid) pure
 {
     return Event(value, start, end, anchor, tag, EventID.Scalar, style, implicit[0],
                  implicit[1]);

dyaml/flags.d

@@ -35,6 +35,8 @@ package:
 struct Flags(names ...) if(names.length <= 8)
 {
     private:
+        @disable int opCmp(ref Flags);
+
         ///Byte storing the flags.
         ubyte flags_;
 

dyaml/loader.d

@@ -117,6 +117,8 @@ struct Loader
 
     public:
         @disable this();
+        @disable int opCmp(ref Loader);
+        @disable bool opEquals(ref Loader);
 
         /**
          * Construct a Loader to load YAML from a file.

dyaml/node.d

@@ -746,7 +746,7 @@ struct Node
             }
             else if(isMapping())
             {
-                auto idx = findPair(index);
+                const idx = findPair(index);
                 if(idx < 0){add(index, value);}
                 else
                 {
@@ -1033,7 +1033,7 @@ struct Node
             }
             else if(isMapping())
             {
-                auto idx = findPair!(T, true)(value);
+                const idx = findPair!(T, true)(value);
                 if(idx >= 0)
                 {
                     auto pairs = as!(Node.Pair[])();
@@ -1099,7 +1099,7 @@ struct Node
             }
             else if(isMapping())
             {
-                auto idx = findPair(index);
+                const idx = findPair(index);
                 if(idx >= 0)
                 {
                     auto pairs = get!(Node.Pair[])();
@@ -1185,9 +1185,9 @@ struct Node
                     const c2 = rhs.value_.get!(const T);
                     if(c1 is c2){return true;}
                     if(c1.length != c2.length){return false;}
-                    foreach(ref i1, ref i2; lockstep(c1, c2))
+                    foreach(i; 0 .. c1.length)
                     {
-                        if(!i1.equals!useTag(i2)){return false;}
+                        if(!c1[i].equals!useTag(c2[i])){return false;}
                     }
                     return true;
                 }

dyaml/parser.d

@@ -347,7 +347,7 @@ final class Parser
             {
                 immutable token = scanner_.getToken();
                 //Name and value are separated by '\0'.
-                auto parts = token.value.split("\0");
+                const parts = token.value.split("\0");
                 const name = parts[0];
                 if(name == "YAML")
                 {
@@ -367,8 +367,7 @@ final class Parser
                     foreach(ref pair; tagDirectives_)
                     {
                         //handle
-                        auto h = pair[0];
+                        const h = pair[0];
-                        auto replacement = pair[1];
                         enforce(h != handle, new Error("Duplicate tag handle: " ~ handle,
                                                        token.startMark));
                     }
@@ -382,14 +381,11 @@ final class Parser
             foreach(ref defaultPair; defaultTagDirectives_)
             {
                 bool found = false;
-                foreach(ref pair; tagDirectives_)
+                foreach(ref pair; tagDirectives_) if(defaultPair[0] == pair[0])
-                {
-                    if(defaultPair[0] == pair[0] )
                 {
                     found = true;
                     break;
                 }
-                }
                 if(!found){tagDirectives_ ~= defaultPair;}
             }
 
@@ -415,7 +411,7 @@ final class Parser
          */
 
         ///Parse a node.
-        Event parseNode(bool block, bool indentlessSequence = false)
+        Event parseNode(in bool block, in bool indentlessSequence = false)
         {
             if(scanner_.checkToken(TokenID.Alias))
             {
@@ -861,8 +857,6 @@ final class Parser
         ///Return an empty scalar.
         Event processEmptyScalar(in Mark mark)
         {
-            //PyYAML uses a Tuple!(true, false) for the second last arg here,
-            //but the second bool is never used after that - so we don't use it.
             return scalarEvent(mark, mark, Anchor(), Tag(), tuple(true, false), "");
         }
 }

dyaml/queue.d

@@ -52,6 +52,8 @@ struct Queue(T)
 
     public:
         @disable void opAssign(ref Queue);
+        @disable bool opEquals(ref Queue);
+        @disable int opCmp(ref Queue);
 
         ///Destroy the queue, deallocating all its elements.
         ~this()

dyaml/reader.d

@@ -103,7 +103,7 @@ final class Reader
             {
                 case -1: 
                     //readBOM() eats two more bytes in this case so get them back
-                    wchar bytes = stream_.getcw();
+                    const wchar bytes = stream_.getcw();
                     rawBuffer8_[0] = cast(char)(bytes % 256);
                     rawBuffer8_[1] = cast(char)(bytes / 256);
                     rawUsed_ = 2;
@@ -444,7 +444,7 @@ final class Reader
          *
          * Returns: True if all the characters are printable, false otherwise.
          */
-        static bool printable(const ref dchar[] chars)
+        static bool printable(const ref dchar[] chars) pure
         {
             foreach(c; chars)
             {
@@ -460,7 +460,7 @@ final class Reader
         }
 
         ///Are we done reading?
-        @property bool done()
+        @property bool done() const
         {   
             return (available_ == 0 && 
                     ((encoding_ == Encoding.UTF_8  && rawUsed_ == 0) ||

dyaml/representer.d

@@ -54,6 +54,9 @@ final class Representer
         CollectionStyle defaultCollectionStyle_ = CollectionStyle.Invalid;
 
     public:
+        @disable bool opEquals(ref Representer);
+        @disable int opCmp(ref Representer);
+
         /**
          * Construct a Representer.
          * 
@@ -62,8 +65,9 @@ final class Representer
          *                                   disabled to use custom representer
          *                                   functions for default types.
          */
-        this(bool useDefaultRepresenters = true)
+        this(in bool useDefaultRepresenters = true)
         {
+            if(!useDefaultRepresenters){return;}
             addRepresenter!YAMLNull(&representNull);
             addRepresenter!string(&representString);
             addRepresenter!(ubyte[])(&representBytes);
@@ -83,13 +87,13 @@ final class Representer
         }
 
         ///Set default _style for scalars. Invalid means the _style is chosen automatically.
-        @property void defaultScalarStyle(ScalarStyle style)
+        @property void defaultScalarStyle(in ScalarStyle style)
         {
             defaultScalarStyle_ = style;
         }
 
         ///Set default _style for collections. Invalid means the _style is chosen automatically. 
-        @property void defaultCollectionStyle(CollectionStyle style)
+        @property void defaultCollectionStyle(in CollectionStyle style)
         {
             defaultCollectionStyle_ = style;
         }

dyaml/resolver.d

@@ -50,6 +50,9 @@ final class Resolver
         Tuple!(Tag, Regex!char)[][dchar] yamlImplicitResolvers_;
 
     public:
+        @disable bool opEquals(ref Resolver);
+        @disable int opCmp(ref Resolver);
+
         /**
          * Construct a Resolver.
          *
@@ -138,7 +141,7 @@ final class Resolver
          *
          * Returns: Resolved tag.
          */
-        Tag resolve(NodeID kind, Tag tag, string value, in bool implicit)
+        Tag resolve(in NodeID kind, Tag tag, string value, in bool implicit)
         {
             if(!tag.isNull() && tag.get() != "!"){return tag;}
 

dyaml/scanner.d

@@ -182,7 +182,7 @@ final class Scanner
          *          or if there are any tokens left if no types specified.
          *          false otherwise.
          */
-        bool checkToken(TokenID[] ids ...)
+        bool checkToken(in TokenID[] ids ...)
         {
             //Check if the next token is one of specified types.
             while(needMoreTokens()){fetchToken();}
@@ -255,7 +255,7 @@ final class Scanner
             unwindIndent(reader_.column);
 
             //Get the next character.
-            dchar c = reader_.peek();
+            const dchar c = reader_.peek();
 
             //Fetch the token.
             if(c == '\0')                  {return fetchStreamEnd();}
@@ -331,7 +331,7 @@ final class Scanner
         void savePossibleSimpleKey()
         {
             //Check if a simple key is required at the current position.
-            bool required = (flowLevel_ == 0 && indent_ == reader_.column);
+            const required = (flowLevel_ == 0 && indent_ == reader_.column);
             assert(allowSimpleKey_ || !required, "A simple key is required only if it is "
                    "the first token in the current line. Therefore it is always allowed.");
 
@@ -339,7 +339,7 @@ final class Scanner
 
             //The next token might be a simple key, so save its number and position.
             removePossibleSimpleKey();
-            uint tokenCount = tokensTaken_ + cast(uint)tokens_.length;
+            const tokenCount = tokensTaken_ + cast(uint)tokens_.length;
 
             const line = reader_.line;
             const column = reader_.column;
@@ -379,7 +379,7 @@ final class Scanner
          *
          * Params:  column = Current column in the file/stream.
          */
-        void unwindIndent(int column)
+        void unwindIndent(in int column)
         {
             if(flowLevel_ > 0)
             {
@@ -582,10 +582,10 @@ final class Scanner
             if(possibleSimpleKeys_.length > flowLevel_ && 
                !possibleSimpleKeys_[flowLevel_].isNull)
             {
-                auto key = possibleSimpleKeys_[flowLevel_];
+                const key = possibleSimpleKeys_[flowLevel_];
                 possibleSimpleKeys_[flowLevel_].isNull = true;
                 Mark keyMark = Mark(key.line, key.column);
-                auto idx = key.tokenIndex - tokensTaken_;
+                const idx = key.tokenIndex - tokensTaken_;
 
                 assert(idx >= 0);
 
@@ -922,7 +922,7 @@ final class Scanner
         dstring scanTagDirectiveValue(in Mark startMark)
         {
             findNextNonSpace();
-            dstring handle = scanTagDirectiveHandle(startMark);
+            const handle = scanTagDirectiveHandle(startMark);
             findNextNonSpace();
             return handle ~ '\0' ~ scanTagDirectivePrefix(startMark);
         }
@@ -979,7 +979,7 @@ final class Scanner
         {
             const startMark = reader_.mark;
 
-            dchar i = reader_.get();
+            const dchar i = reader_.get();
 
             dstring value = i == '*' ? scanAlphaNumeric!("an alias")(startMark)
                                      : scanAlphaNumeric!("an anchor")(startMark); 
@@ -1058,7 +1058,7 @@ final class Scanner
         }
 
         ///Scan a block scalar token with specified style.
-        Token scanBlockScalar(ScalarStyle style)
+        Token scanBlockScalar(in ScalarStyle style)
         {
             const startMark = reader_.mark;
 
@@ -1234,7 +1234,7 @@ final class Scanner
         }
 
         ///Scan a qouted flow scalar token with specified quotes.
-        Token scanFlowScalar(ScalarStyle quotes)
+        Token scanFlowScalar(in ScalarStyle quotes)
         {
             const startMark = reader_.mark;
             const quote = reader_.get();
@@ -1256,7 +1256,7 @@ final class Scanner
         }
 
         ///Scan nonspace characters in a flow scalar.
-        void scanFlowScalarNonSpaces(ScalarStyle quotes, in Mark startMark)
+        void scanFlowScalarNonSpaces(in ScalarStyle quotes, in Mark startMark)
         {
             for(;;)
             {
@@ -1423,7 +1423,7 @@ final class Scanner
                 for(;;)
                 {
                     c = reader_.peek(length);
-                    bool done = search.canFind(c) || (flowLevel_ == 0 && c == ':' && 
+                    const bool done = search.canFind(c) || (flowLevel_ == 0 && c == ':' && 
                                       search.canFind(reader_.peek(length + 1))) ||
                                       (flowLevel_ > 0 && ",:?[]{}"d.canFind(c));
                     if(done){break;}
@@ -1509,7 +1509,7 @@ final class Scanner
         }
 
         ///Scan handle of a tag token.
-        dstring scanTagHandle(string name, in Mark startMark)
+        dstring scanTagHandle(in string name, in Mark startMark)
         {
             dchar c = reader_.peek();
             enforce(c == '!', 
@@ -1538,7 +1538,7 @@ final class Scanner
         }
 
         ///Scan URI in a tag token.
-        dstring scanTagURI(string name, in Mark startMark)
+        dstring scanTagURI(in string name, in Mark startMark)
         {
             //Note: we do not check if URI is well-formed.
             //Using appender_, so clear it when we're done.
@@ -1570,7 +1570,7 @@ final class Scanner
         }
 
         ///Scan URI escape sequences.
-        dstring scanURIEscapes(string name, in Mark startMark)
+        dstring scanURIEscapes(in string name, in Mark startMark)
         {
             ubyte[] bytes;
             Mark mark = reader_.mark;
@@ -1584,7 +1584,7 @@ final class Scanner
                 //Converting 2 hexadecimal digits to a byte.
                 foreach(k; 0 .. 2)
                 {
-                    dchar c = reader_.peek(k);
+                    const dchar c = reader_.peek(k);
                     enforce(isHexDigit(c),
                             new Error("While scanning a " ~ name, startMark, 
                                       "expected URI escape sequence of "

dyaml/serializer.d

@@ -69,7 +69,7 @@ struct Serializer
          *          tagDirectives = Tag directives to emit. 
          */
         this(ref Emitter emitter, Resolver resolver, Encoding encoding,
-             bool explicitStart, bool explicitEnd, string YAMLVersion, 
+             in bool explicitStart, in bool explicitEnd, string YAMLVersion, 
              TagDirectives tagDirectives)
         {
             emitter_ = &emitter;
@@ -200,7 +200,7 @@ struct Serializer
             if(node.isSequence)
             {
                 const defaultTag = resolver_.defaultSequenceTag;
-                bool implicit = node.tag_ == defaultTag;
+                const implicit = node.tag_ == defaultTag;
                 emitter_.emit(sequenceStartEvent(Mark(), Mark(), aliased, node.tag_,
                                                  implicit, node.collectionStyle));
                 foreach(ref Node item; node)
@@ -212,8 +212,8 @@ struct Serializer
             }
             if(node.isMapping)
             {
-                auto defaultTag = resolver_.defaultMappingTag; 
+                const defaultTag = resolver_.defaultMappingTag; 
-                bool implicit = node.tag_ == defaultTag;
+                const implicit = node.tag_ == defaultTag;
                 emitter_.emit(mappingStartEvent(Mark(), Mark(), aliased, node.tag_,
                                                 implicit, node.collectionStyle));
                 foreach(ref Node key, ref Node value; node)

dyaml/sharedobject.d

@@ -63,12 +63,9 @@ template SharedObject(T, MixedIn)
                 ///Add an object and return its index.
                 uint add(ref T object)
                 {
-                    foreach(uint index, ref T known; objects_)
+                    foreach(index, ref known; objects_) if(object == known)
                     {
-                        if(object == known)
+                        return cast(uint)index;
-                        {
-                            return index;
-                        }
                     }
                     objects_ ~= object;
                     return cast(uint)objects_.length - 1;

dyaml/tag.d

@@ -19,8 +19,11 @@ struct Tag
         immutable(char)* tag_ = null;
 
     public:
+        @disable int opCmp(ref Tag);
+
+
         ///Construct a tag from a string representation.
-        this(string tag)
+        this(in string tag)
         {
             if(tag is null || tag == "")
             {

dyaml/token.d

@@ -53,6 +53,8 @@ enum TokenID : ubyte
  */
 struct Token 
 {
+    @disable int opCmp(ref Token);
+
     ///Value of the token, if any.
     string value;
     ///Start position of the token in file/stream.
@@ -101,7 +103,7 @@ Token simpleToken(TokenID id)(in Mark start, in Mark end) pure
  *          end      = End position of the token.
  *          encoding = Encoding of the stream.
  */
-Token streamStartToken(in Mark start, in Mark end, in Encoding encoding)
+Token streamStartToken(in Mark start, in Mark end, in Encoding encoding) pure
 {
     return Token(null, start, end, TokenID.StreamStart, ScalarStyle.Invalid, encoding);
 }