Simplify streaming API and improve pretty printing

This removes the obligation from the caller to correctly maintain flags to
describe the current anonymous context, instead making the writer handle this
itself as much as possible.  Flags remain for the cases the writer can not
infer from context: the start of anonymous subject and object nodes.

3 files changed, 98 insertions, 2 deletions

diff --git a/tests/good/base.ttl b/tests/good/base.ttl
index 4c437937..755c1d09 100644
--- a/tests/good/base.ttl
+++ b/tests/good/base.ttl
@@ -1,3 +1,2 @@
 <foo>
 	a <Bar> .
-
diff --git a/tests/good/pretty.trig b/tests/good/pretty.trig
new file mode 100644
index 00000000..140769ce
--- /dev/null
+++ b/tests/good/pretty.trig
@@ -0,0 +1,98 @@
+@prefix : <http://example.org/> .
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+
+:a
+	:b :c ,
+		:d ,
+		:e ;
+	:f :g ,
+		:h .
+
+(
+	1
+)
+	:isA :List .
+
+[]
+	:isA :Blank .
+
+(
+	2
+)
+	:sameAs (
+		2
+	) .
+
+[]
+	:sameAs [] .
+
+(
+	1
+	2
+)
+	a :List ;
+	rdf:value 3 .
+
+(
+	(
+		3
+	)
+	(
+		4
+	)
+)
+	a :NestedList ;
+	:sum 7 .
+
+[
+	a :BlankSubject
+]
+	a rdf:Resource .
+
+[
+	a :BlankSubject
+] .
+
+[]
+	:blank [
+		:nestedEmptyBlank [] ;
+		:nestedNonEmptyBlanks [
+			rdf:value 1
+		] , [
+			rdf:value 2
+		]
+	] ;
+	:lists (
+		3
+		4
+	) , (
+		5
+		6
+	) , (
+		[
+			rdf:value 7
+		]
+		[
+			rdf:value 8
+		]
+	) .
+
+:s
+	a :Thing ;
+	:predicate1 :object1 ,
+	[
+		a :SubThing ;
+		:predicate2 :object2
+	] , [
+		a :OtherSubThing ;
+		:p3 :o3
+	] ;
+	:p4 :o4 .
+
+eg:graph {
+	:a
+		:b :c ;
+		:d [
+			:e :f
+		] .
+}
diff --git a/tests/good/qualify-out.ttl b/tests/good/qualify-out.ttl
index 97f67a53..42e4091a 100644
--- a/tests/good/qualify-out.ttl
+++ b/tests/good/qualify-out.ttl
@@ -2,4 +2,3 @@
 
 eg:s
 	eg:p eg:o .
-