diff --git a/src/rio/ntriples/grammar.rustpeg b/src/rio/ntriples/grammar.rustpeg
index 3ba8c951..a1d7317c 100644
--- a/src/rio/ntriples/grammar.rustpeg
+++ b/src/rio/ntriples/grammar.rustpeg
@@ -10,50 +10,62 @@ use model::data::*;
 triple -> Option<Triple> =
     _ s:subject _ p:predicate _ o:object _ "." _ comment? { Some(data_factory.triple(s, p, o)) } /
     _ comment? { None }
+
 //[3]
 subject -> NamedOrBlankNode =
     i: IRIREF { data_factory.named_node(i).into() } /
     b: BLANK_NODE_LABEL { data_factory.blank_node(b).into() }
+
 //[4]
 predicate -> NamedNode = i:IRIREF {
     data_factory.named_node(i)
 }
+
 //[5]
 object -> Term =
     i: IRIREF { data_factory.named_node(i).into() } /
     b: BLANK_NODE_LABEL { data_factory.blank_node(b).into() } /
     l: literal { l.into() }
+
 //[6]
 literal -> Literal =
     v: STRING_LITERAL_QUOTE _ "^^" _ t:IRIREF { data_factory.typed_literal(v, data_factory.named_node(t)) } /
     v: STRING_LITERAL_QUOTE _ l:LANGTAG { data_factory.language_tagged_literal(v, l) } /
     v: STRING_LITERAL_QUOTE { data_factory.simple_literal(v) }
 
+
 //[144s]
 LANGTAG -> String = "@" l: $([a-zA-Z]+ ("-" [a-zA-Z0-9]+)*) {
     l.into()
 }
+
 //[7]
 EOL = [\r\n]+
+
 //[8]
-IRIREF -> String = "<" _ i: $(([^<>{}] / UCHAR)*) _ ">" {
-    i.into()
+IRIREF -> String = "<" _ i: ((_IRIREF_simple_char / UCHAR)*) _ ">" {
+    i.into_iter().collect()
 }
+_IRIREF_simple_char -> char = c: $([^\u{00}-\u{20}<>"{}|^\u{60}\u{5c}]) { c.chars().next().unwrap() }
+
 //[9]
-STRING_LITERAL_QUOTE -> String = "\"" l: ((NOT_BAD_LITERAL_VALUE / ECHAR / UCHAR)*) "\"" {
+STRING_LITERAL_QUOTE -> String = "\"" l: ((STRING_LITERAL_QUOTE_simple_char / ECHAR / UCHAR)*) "\"" {
     l.into_iter().collect()
 }
-NOT_BAD_LITERAL_VALUE -> char = c: $([^\u{0022}\u{005c}\u{000a}\u{000d}]) { c.chars().next().unwrap() }
+STRING_LITERAL_QUOTE_simple_char -> char = c: $([^\u{0022}\u{005c}\u{000a}\u{000d}]) { c.chars().next().unwrap() }
+
 //[141s]
 BLANK_NODE_LABEL -> String = "_:" b: $((PN_CHARS_U / [0-9]) ((PN_CHARS / ".")* PN_CHARS)?) {
     b.into()
 }
+
 //[10]
 UCHAR -> char = "\\u" h: $(HEX HEX HEX HEX) {
     u32::from_str_radix(h, 16).ok().and_then(char::from_u32).unwrap()
 } / "\\U" h: $(HEX HEX HEX HEX HEX HEX HEX HEX) {
     u32::from_str_radix(h, 16).ok().and_then(char::from_u32).unwrap()
 }
+
 //[153s]
 ECHAR -> char = '\\' c: $([tbnrf"'\\]) {
     match c {
@@ -68,35 +80,20 @@ ECHAR -> char = '\\' c: $([tbnrf"'\\]) {
         _ => panic!("unexpected escaped char") // not possible
     }
 }
+
 //[157s]
-PN_CHARS_BASE -> char = c: $([A-Za-z\u{00C0}-\u{00D6}\u{00D8}-\u{00F6}\u{00F8}-\u{02FF}\u{0370}-\u{037D}\u{037F}-\u{1FFF}\u{200C}-\u{200D}\u{2070}-\u{218F}\u{2C00}-\u{2FEF}\u{3001}-\u{D7FF}\u{F900}-\u{FDCF}\u{FDF0}-\u{FFFD}]) { c.chars().next().unwrap() }
+PN_CHARS_BASE -> () = [A-Za-z\u{00C0}-\u{00D6}\u{00D8}-\u{00F6}\u{00F8}-\u{02FF}\u{0370}-\u{037D}\u{037F}-\u{1FFF}\u{200C}-\u{200D}\u{2070}-\u{218F}\u{2C00}-\u{2FEF}\u{3001}-\u{D7FF}\u{F900}-\u{FDCF}\u{FDF0}-\u{FFFD}]
+
 //[158s]
-PN_CHARS_U -> char = PN_CHARS_BASE / '_' { '_' } / ':' { ':' }
+PN_CHARS_U -> () = PN_CHARS_BASE / '_' / ':'
+
 //[160s]
-PN_CHARS -> char = PN_CHARS_U / c: $([\-0-9\u{00B7}\u{0300}-\u{036F}\u{203F}-\u{2040}]) { c.chars().next().unwrap() }
+PN_CHARS -> () = PN_CHARS_U / [\-0-9\u{00B7}\u{0300}-\u{036F}\u{203F}-\u{2040}]
+
 //[162s]
-HEX -> char = c: $([0-9A-Fa-f]) { c.chars().next().unwrap() }
+HEX -> () = ([0-9A-Fa-f])
 
 //space
 _ = #quiet<[ \t]*>
 //comment
 comment = #quiet<"#" [^\r\n]*>
-
-
-/*grammar;
-
-pub NTripleLine: Option<Triple> = {
-    Comment? => None,
-    <t:NTriple> Comment? => Some(t)
-};
-pub NQuadLine: Option<Quad> = {
-    Comment? => None,
-    <t:NQuad> Comment? => Some(t)
-};
-
-NTriple: Triple = <s:Node> <p:IRI> <o:RDFTerm> "." => data_factory.triple(s, p, o);
-NQuad: Quad = {
-    <s:Node> <p:IRI> <o:RDFTerm> <g:Node> "." => data_factory.quad(s, p, o, Some(g)),
-    <s:Node> <p:IRI> <o:RDFTerm> "." => data_factory.quad(s, p, o, None)
-};
-*/
\ No newline at end of file
diff --git a/src/rio/ntriples/mod.rs b/src/rio/ntriples/mod.rs
index c6a1629c..ac52aec4 100644
--- a/src/rio/ntriples/mod.rs
+++ b/src/rio/ntriples/mod.rs
@@ -9,14 +9,12 @@ use rio::*;
 use std::io::BufRead;
 use std::io::BufReader;
 use std::io::Read;
-use std::sync::Arc;
 
 pub fn read_ntriples<'a, R: Read + 'a>(
     source: R,
     data_factory: &'a DataFactory,
 ) -> impl Iterator<Item = RioResult<Triple>> {
     let factory = data_factory.clone(); //TODO: try to avoid clone here
-    let mut input = String::new();
     //TODO: use read_lines to avoid allocations
     BufReader::new(source)
         .lines()