tagged literals for edn reader, new sigs for read-edn, read-edn-string

Author: richhickey

src/clj/clojure/core.clj

@@ -3406,23 +3406,6 @@
   ([stream eof-error? eof-value recursive?]
    (. clojure.lang.LispReader (read stream (boolean eof-error?) eof-value recursive?))))
 
-(defn read-edn
-  "Reads the next object from stream, which must be an instance of
-  java.io.PushbackReader or some derivee.  stream defaults to the
-  current value of *in*.
-
-  Reads data in the edn format (subset of Clojure data):
-  http://edn-format.org"
-  {:added "1.5"}
-  ([]
-   (read-edn *in*))
-  ([stream]
-   (read-edn stream true nil))
-  ([stream eof-error? eof-value]
-   (read-edn stream eof-error? eof-value false))
-  ([stream eof-error? eof-value recursive?]
-     (. clojure.lang.EdnReader (read stream (boolean eof-error?) eof-value recursive?))))
-
 (defn read-line
   "Reads the next line from stream that is the current value of *in* ."
   {:added "1.0"
@@ -3443,13 +3426,39 @@
    :static true}
   [s] (clojure.lang.RT/readString s))
 
+(defn read-edn
+  "Reads the next object from stream, which must be an instance of
+  java.io.PushbackReader or some derivee.  stream defaults to the
+  current value of *in*.
+
+  Reads data in the edn format (subset of Clojure data):
+  http://edn-format.org
+
+  opts is a map that can include the following keys:
+  :eof - value to return on end-of-file. When not supplied, eof throws an exception.
+  :readers  - a map of tag symbols to data-reader functions to be considered before *default-data-readers*.
+              When not supplied, only the *default-data-readers* will be used.
+  :default - A function of two args, that will, if present and no reader is found for a tag,
+             be called with the tag and the value."
+  
+  {:added "1.5"}
+  ([]
+   (read-edn *in*))
+  ([stream]
+   (read-edn {} stream))
+  ([opts stream]
+     (clojure.lang.EdnReader/read stream opts)))
+
 (defn read-edn-string
   "Reads one object from the string s. Returns nil when s is nil or empty.
 
   Reads data in the edn format (subset of Clojure data):
-  http://edn-format.org"
+  http://edn-format.org
+
+  opts is a map as per read-edn"
   {:added "1.5"}
-  [s] (when (pos? (count s)) (clojure.lang.EdnReader/readString s)))
+  ([s] (read-edn-string {:eof nil} s))
+  ([opts s] (when s (clojure.lang.EdnReader/readString s opts))))
 
 (defn subvec
   "Returns a persistent vector of the items in vector from

src/jvm/clojure/lang/EdnReader.java

@@ -32,6 +32,8 @@ public class EdnReader{
 static Pattern floatPat = Pattern.compile("([-+]?[0-9]+(\\.[0-9]*)?([eE][-+]?[0-9]+)?)(M)?");
 static final Symbol SLASH = Symbol.intern("/");
 
+static IFn taggedReader = new TaggedReader();
+
 static
 	{
 	macros['"'] = new StringReader();
@@ -54,10 +56,14 @@ public class EdnReader{
 	dispatchMacros['_'] = new DiscardReader();
 	}
 
-static public Object readString(String s){
+static boolean nonConstituent(int ch){
+	return ch == '@' || ch == '`' || ch == '~';
+}
+
+static public Object readString(String s, IPersistentMap opts){
 	PushbackReader r = new PushbackReader(new java.io.StringReader(s));
 	try {
-	return EdnReader.read(r, true, null, false);
+	return read(r, opts);
 	}
 	catch(Exception e) {
 	throw Util.sneakyThrow(e);
@@ -102,7 +108,14 @@ static public int read1(Reader r){
 		}
 }
 
-static public Object read(PushbackReader r, boolean eofIsError, Object eofValue, boolean isRecursive)
+static final Keyword EOF = Keyword.intern(null,"eof");
+
+static public Object read(PushbackReader r, IPersistentMap opts){
+	return read(r,!opts.containsKey(EOF),opts.valAt(EOF),false,opts);
+}
+
+static public Object read(PushbackReader r, boolean eofIsError, Object eofValue, boolean isRecursive,
+                          Object opts)
 {
 
 	try
@@ -132,7 +145,7 @@ static public Object read(PushbackReader r, boolean eofIsError, Object eofValue,
 			IFn macroFn = getMacro(ch);
 			if(macroFn != null)
 				{
-				Object ret = macroFn.invoke(r, (char) ch);
+				Object ret = macroFn.invoke(r, (char) ch, opts);
 				if(RT.suppressRead())
 					return null;
 				//no op macros return the reader
@@ -173,16 +186,22 @@ static public Object read(PushbackReader r, boolean eofIsError, Object eofValue,
 
 static private String readToken(PushbackReader r, char initch) {
 	StringBuilder sb = new StringBuilder();
+	if(nonConstituent(initch))
+		throw Util.runtimeException("Invalid leading character: " + (char)initch);
+
 	sb.append(initch);
 
 	for(; ;)
 		{
 		int ch = read1(r);
+
 		if(ch == -1 || isWhitespace(ch) || isTerminatingMacro(ch))
 			{
 			unread(r, ch);
 			return sb.toString();
 			}
+		else if(nonConstituent(ch))
+			throw Util.runtimeException("Invalid constituent character: " + (char)ch);
 		sb.append((char) ch);
 		}
 }
@@ -391,7 +410,7 @@ public Object invoke(Object reader, Object doublequote) {
 */
 
 public static class StringReader extends AFn{
-	public Object invoke(Object reader, Object doublequote) {
+	public Object invoke(Object reader, Object doublequote, Object opts) {
 		StringBuilder sb = new StringBuilder();
 		Reader r = (Reader) reader;
 
@@ -453,7 +472,7 @@ public Object invoke(Object reader, Object doublequote) {
 }
 
 public static class CommentReader extends AFn{
-	public Object invoke(Object reader, Object semicolon) {
+	public Object invoke(Object reader, Object semicolon, Object opts) {
 		Reader r = (Reader) reader;
 		int ch;
 		do
@@ -466,29 +485,36 @@ public Object invoke(Object reader, Object semicolon) {
 }
 
 public static class DiscardReader extends AFn{
-	public Object invoke(Object reader, Object underscore) {
+	public Object invoke(Object reader, Object underscore, Object opts) {
 		PushbackReader r = (PushbackReader) reader;
-		read(r, true, null, true);
+		read(r, true, null, true, opts);
 		return r;
 	}
 }
 
 public static class DispatchReader extends AFn{
-	public Object invoke(Object reader, Object hash) {
+	public Object invoke(Object reader, Object hash, Object opts) {
 		int ch = read1((Reader) reader);
 		if(ch == -1)
 			throw Util.runtimeException("EOF while reading character");
 		IFn fn = dispatchMacros[ch];
 
 		if(fn == null) {
+			//try tagged reader
+		    if(Character.isLetter(ch))
+				{
+				unread((PushbackReader) reader, ch);
+		        return taggedReader.invoke(reader, ch, opts);
+				}
+
 			throw Util.runtimeException(String.format("No dispatch macro for: %c", (char) ch));
 		}
-		return fn.invoke(reader, ch);
+		return fn.invoke(reader, ch, opts);
 	}
 }
 
 public static class MetaReader extends AFn{
-	public Object invoke(Object reader, Object caret) {
+	public Object invoke(Object reader, Object caret, Object opts) {
 		PushbackReader r = (PushbackReader) reader;
 		int line = -1;
 		int column = -1;
@@ -497,15 +523,15 @@ public Object invoke(Object reader, Object caret) {
 			line = ((LineNumberingPushbackReader) r).getLineNumber();
 			column = ((LineNumberingPushbackReader) r).getColumnNumber()-1;
 			}
-		Object meta = read(r, true, null, true);
+		Object meta = read(r, true, null, true, opts);
 		if(meta instanceof Symbol || meta instanceof String)
 			meta = RT.map(RT.TAG_KEY, meta);
 		else if (meta instanceof Keyword)
 			meta = RT.map(meta, RT.T);
 		else if(!(meta instanceof IPersistentMap))
 			throw new IllegalArgumentException("Metadata must be Symbol,Keyword,String or Map");
 
-		Object o = read(r, true, null, true);
+		Object o = read(r, true, null, true, opts);
 		if(o instanceof IMeta)
 			{
 			if(line != -1 && o instanceof ISeq)
@@ -531,7 +557,7 @@ else if(!(meta instanceof IPersistentMap))
 }
 
 public static class CharacterReader extends AFn{
-	public Object invoke(Object reader, Object backslash) {
+	public Object invoke(Object reader, Object backslash, Object opts) {
 		PushbackReader r = (PushbackReader) reader;
 		int ch = read1(r);
 		if(ch == -1)
@@ -574,7 +600,7 @@ else if(token.startsWith("o"))
 }
 
 public static class ListReader extends AFn{
-	public Object invoke(Object reader, Object leftparen) {
+	public Object invoke(Object reader, Object leftparen, Object opts) {
 		PushbackReader r = (PushbackReader) reader;
 		int line = -1;
 		int column = -1;
@@ -583,7 +609,7 @@ public Object invoke(Object reader, Object leftparen) {
 			line = ((LineNumberingPushbackReader) r).getLineNumber();
 			column = ((LineNumberingPushbackReader) r).getColumnNumber()-1;
 			}
-		List list = readDelimitedList(')', r, true);
+		List list = readDelimitedList(')', r, true, opts);
 		if(list.isEmpty())
 			return PersistentList.EMPTY;
 		IObj s = (IObj) PersistentList.create(list);
@@ -599,17 +625,17 @@ public Object invoke(Object reader, Object leftparen) {
 }
 
 public static class VectorReader extends AFn{
-	public Object invoke(Object reader, Object leftparen) {
+	public Object invoke(Object reader, Object leftparen, Object opts) {
 		PushbackReader r = (PushbackReader) reader;
-		return LazilyPersistentVector.create(readDelimitedList(']', r, true));
+		return LazilyPersistentVector.create(readDelimitedList(']', r, true, opts));
 	}
 
 }
 
 public static class MapReader extends AFn{
-	public Object invoke(Object reader, Object leftparen) {
+	public Object invoke(Object reader, Object leftparen, Object opts) {
 		PushbackReader r = (PushbackReader) reader;
-		Object[] a = readDelimitedList('}', r, true).toArray();
+		Object[] a = readDelimitedList('}', r, true, opts).toArray();
 		if((a.length & 1) == 1)
 			throw Util.runtimeException("Map literal must contain an even number of forms");
 		return RT.map(a);
@@ -618,27 +644,27 @@ public Object invoke(Object reader, Object leftparen) {
 }
 
 public static class SetReader extends AFn{
-	public Object invoke(Object reader, Object leftbracket) {
+	public Object invoke(Object reader, Object leftbracket, Object opts) {
 		PushbackReader r = (PushbackReader) reader;
-		return PersistentHashSet.createWithCheck(readDelimitedList('}', r, true));
+		return PersistentHashSet.createWithCheck(readDelimitedList('}', r, true, opts));
 	}
 
 }
 
 public static class UnmatchedDelimiterReader extends AFn{
-	public Object invoke(Object reader, Object rightdelim) {
+	public Object invoke(Object reader, Object rightdelim, Object opts) {
 		throw Util.runtimeException("Unmatched delimiter: " + rightdelim);
 	}
 
 }
 
 public static class UnreadableReader extends AFn{
-	public Object invoke(Object reader, Object leftangle) {
+	public Object invoke(Object reader, Object leftangle, Object opts) {
 		throw Util.runtimeException("Unreadable form");
 	}
 }
 
-public static List readDelimitedList(char delim, PushbackReader r, boolean isRecursive) {
+public static List readDelimitedList(char delim, PushbackReader r, boolean isRecursive, Object opts) {
 	final int firstline =
 			(r instanceof LineNumberingPushbackReader) ?
 			((LineNumberingPushbackReader) r).getLineNumber() : -1;
@@ -666,7 +692,7 @@ public static List readDelimitedList(char delim, PushbackReader r, boolean isRec
 		IFn macroFn = getMacro(ch);
 		if(macroFn != null)
 			{
-			Object mret = macroFn.invoke(r, (char) ch);
+			Object mret = macroFn.invoke(r, (char) ch, opts);
 			//no op macros return the reader
 			if(mret != r)
 				a.add(mret);
@@ -675,7 +701,7 @@ public static List readDelimitedList(char delim, PushbackReader r, boolean isRec
 			{
 			unread(r, ch);
 
-			Object o = read(r, true, null, isRecursive);
+			Object o = read(r, true, null, isRecursive, opts);
 			if(o != r)
 				a.add(o);
 			}
@@ -685,5 +711,37 @@ public static List readDelimitedList(char delim, PushbackReader r, boolean isRec
 	return a;
 }
 
+public static class TaggedReader extends AFn{
+	public Object invoke(Object reader, Object firstChar, Object opts){
+		PushbackReader r = (PushbackReader) reader;
+		Object name = read(r, true, null, false, opts);
+		if (!(name instanceof Symbol))
+			throw new RuntimeException("Reader tag must be a symbol");
+		Symbol sym = (Symbol)name;
+		return readTagged(r, sym, (IPersistentMap) opts);
+	}
+
+	static Keyword READERS = Keyword.intern(null,"readers");
+	static Keyword DEFAULT = Keyword.intern(null,"default");
+
+	private Object readTagged(PushbackReader reader, Symbol tag, IPersistentMap opts){
+		Object o = read(reader, true, null, true, opts);
+
+		ILookup readers = (ILookup)RT.get(opts, READERS);
+		IFn dataReader = (IFn)RT.get(readers, tag);
+		if(dataReader == null)
+			dataReader = (IFn)RT.get(RT.DEFAULT_DATA_READERS.deref(),tag);
+		if(dataReader == null){
+			IFn defaultReader = (IFn)RT.get(opts, DEFAULT);
+			if(defaultReader != null)
+				return defaultReader.invoke(tag, o);
+			else
+				throw new RuntimeException("No reader function for tag " + tag.toString());
+		}
+		else
+			return dataReader.invoke(o);
+	}
+
+}
 }
 

src/jvm/clojure/lang/LispReader.java

@@ -424,7 +424,7 @@ static private boolean isMacro(int ch){
 }
 
 static private boolean isTerminatingMacro(int ch){
-	return (ch != '#' && ch != '\'' && isMacro(ch));
+	return (ch != '#' && ch != '\'' && ch != '%' && isMacro(ch));
 }
 
 public static class RegexReader extends AFn{