Fixed bugs in presenter, serialization, README

* Made presenter output numbers without double quotes in
   JSON style again
 * Fixed broken serialization.load
 * Updated examples in README

README.md

@@ -26,7 +26,7 @@ a list:
 """
 
 var
-  parser = newParser(coreTagLibrary())
+  parser = newYamlParser(initCoreTagLibrary())
   events = parser.parse(newStringStream(input))
 
 for event in events():
@@ -60,13 +60,13 @@ import yaml, streams
 proc example(): YamlStream =
   result = iterator(): YamlStreamEvent =
     yield startDocEvent()
-    yield startMapEvent(mayHaveKeyObjects = false)
+    yield startMapEvent()
     yield scalarEvent("an integer")
     yield scalarEvent("42", tag = yTagInteger)
     yield scalarEvent("a list")
     yield startSeqEvent(tag = yTagSequence)
     yield scalarEvent("item", tag = yTagString)
-    yield scalarEvent("no", tag = yTagBoolean, typeHint = yTypeBoolFalse)
+    yield scalarEvent("no", tag = yTagBoolean)
     yield scalarEvent("")
     yield endSeqEvent()
     yield scalarEvent("a float")
@@ -74,11 +74,11 @@ proc example(): YamlStream =
     yield endMapEvent()
     yield endDocEvent()
 
-present(example(), newFileStream(stdout), coreTagLibrary(), yDumpBlockOnly)
+present(example(), newFileStream(stdout), initCoreTagLibrary(), psBlockOnly)
 echo "\n\n"
-present(example(), newFileStream(stdout), coreTagLibrary(), yDumpCanonical)
+present(example(), newFileStream(stdout), initCoreTagLibrary(), psCanonical)
 echo "\n\n"
-present(example(), newFileStream(stdout), coreTagLibrary(), yDumpJson)
+present(example(), newFileStream(stdout), initCoreTagLibrary(), psJson)
 ```
 
 Output:
@@ -129,7 +129,7 @@ a float: !!float 3.14159
 import yaml.serialization
 import tables
 
-make_serializable:
+serializable:
     type
         Person = object
             firstname, surname: string
@@ -162,7 +162,7 @@ assert persons[1].additionalAttributes["location"] == "Celle"
 
 # dumping
 
-dump(persons, newFileStream(stdout), ypsCanonical)
+dump(persons, newFileStream(stdout), psCanonical)
 ```
 
 Output:
@@ -177,9 +177,9 @@ Output:
     ? !!str "surname"
     : !!str "Pan",
     ? !!str "age"
-    : !!int "12",
+    : !nim:int "12",
     ? !!str "additionalAttributes"
-    : {
+    : !nim:Table(tag:yaml.org,2002:str,tag:yaml.org,2002:str) {
       ? !!str "canFly"
       : !!str "yes",
       ? !!str "location"
@@ -192,9 +192,9 @@ Output:
     ? !!str "surname"
     : !!str "Koch",
     ? !!str "age"
-    : !!int "23",
+    : !nim:int "23",
     ? !!str "additionalAttributes"
-    : {
+    : !nim:Table(tag:yaml.org,2002:str,tag:yaml.org,2002:str) {
       ? !!str "occupation"
       : !!str "Hacker",
       ? !!str "location"

private/presenter.nim

@@ -208,10 +208,16 @@ proc present*(s: YamlStream, target: Stream, tagLib: TagLibrary,
                 elif item.scalarTag in [yTagQuestionMark, yTagNull] and
                         hint == yTypeNull:
                     safeWrite("null")
+                elif item.scalarTag in [yTagQuestionMark, yTagInteger] and
+                        hint == yTypeInteger:
+                    safeWrite(item.scalarContent)
                 elif item.scalarTag in [yTagQuestionMark, yTagFloat] and
                         hint in [yTypeFloatInf, yTypeFloatNaN]:
                     raise newException(YamlPresenterJsonError,
                             "Infinity and not-a-number values cannot be presented as JSON!")
+                elif item.scalarTag in [yTagQuestionMark, yTagFloat] and
+                        hint == yTypeFloat:
+                    safeWrite(item.scalarContent)
                 else:
                     writeDoubleQuoted(item.scalarContent, target)
             elif style == psCanonical or item.scalarContent.needsEscaping:

yaml/serialization.nim

@@ -473,13 +473,27 @@ proc serialize*[K, V](value: Table[K, V],
         yield YamlStreamEvent(kind: yamlEndMap)
 
 proc load*[K](input: Stream, target: var K)
-        {.raises: [YamlConstructionError, YamlConstructionStreamError].} =
-    var
-        tagLib = serializationTagLibrary
-        events = parse(tagLib, input)
-    assert events().kind == yamlStartDocument
-    construct(events, target)
-    assert events().kind == yamlEndDocument
+        {.raises: [YamlConstructionError, IOError, YamlParserError].} =
+    try:
+        var
+            parser = newYamlParser(serializationTagLibrary)
+            events = parser.parse(input)
+        assert events().kind == yamlStartDocument
+        construct(events, target)
+        assert events().kind == yamlEndDocument
+    except YamlConstructionError, IOError, YamlParserError:
+        raise
+    except YamlConstructionStreamError:
+        let e = cast[ref YamlConstructionError](getCurrentException())
+        if e.parent is IOError:
+            raise cast[ref IOError](e.parent)
+        elif e.parent is YamlParserError:
+            raise cast[ref YamlParserError](e.parent)
+        else:
+            assert(false)
+    except Exception:
+        # compiler bug: https://github.com/nim-lang/Nim/issues/3772
+        assert(false)
 
 proc dump*[K](value: K, target: Stream, style: PresentationStyle = psDefault,
               tagStyle: TagStyle = tsRootOnly, indentationStep: int = 2)