diff --git a/lib/Cargo.toml b/lib/Cargo.toml
index b6e55e86..cb10037e 100644
--- a/lib/Cargo.toml
+++ b/lib/Cargo.toml
@@ -25,11 +25,17 @@ ordered-float = "1"
 num-traits = "0.2"
 rust_decimal = "1"
 chrono = "0.4"
+rand = "0.7"
+md-5 = "0.8"
+sha-1 = "0.8"
+sha2 = "0.8"
+digest = "0.8"
 failure = "0.1"
 regex = "1"
 rio_api = "0.3"
 rio_turtle = "0.3"
 rio_xml = "0.3"
+hex = "0.3"
 
 [build-dependencies]
 peg = "0.5"
diff --git a/lib/src/model/blank_node.rs b/lib/src/model/blank_node.rs
index be37a4c4..4126d5ac 100644
--- a/lib/src/model/blank_node.rs
+++ b/lib/src/model/blank_node.rs
@@ -1,5 +1,6 @@
 use rio_api::model as rio;
 use std::fmt;
+use std::str;
 use uuid::Uuid;
 
 /// A RDF [blank node](https://www.w3.org/TR/rdf11-concepts/#dfn-blank-node).
@@ -15,13 +16,13 @@ use uuid::Uuid;
 #[derive(Eq, PartialEq, Ord, PartialOrd, Debug, Clone, Hash)]
 pub struct BlankNode {
     uuid: Uuid,
-    id: String,
+    str: [u8; 32],
 }
 
 impl BlankNode {
     /// Returns the underlying ID of this blank node
     pub fn as_str(&self) -> &str {
-        &self.id
+        str::from_utf8(&self.str).unwrap()
     }
 
     /// Returns the underlying UUID of this blank node
@@ -45,10 +46,9 @@ impl Default for BlankNode {
 
 impl From<Uuid> for BlankNode {
     fn from(id: Uuid) -> Self {
-        Self {
-            uuid: id,
-            id: id.to_simple().to_string(),
-        }
+        let mut str = [0; 32];
+        id.to_simple().encode_lower(&mut str);
+        Self { uuid: id, str }
     }
 }
 
diff --git a/lib/src/sparql/algebra.rs b/lib/src/sparql/algebra.rs
index cb28bd35..bec20650 100644
--- a/lib/src/sparql/algebra.rs
+++ b/lib/src/sparql/algebra.rs
@@ -3,6 +3,7 @@
 use crate::model::*;
 use crate::sparql::model::*;
 use lazy_static::lazy_static;
+use rio_api::iri::Iri;
 use rio_api::model as rio;
 use std::collections::BTreeMap;
 use std::collections::BTreeSet;
@@ -1203,74 +1204,111 @@ lazy_static! {
     static ref EMPTY_DATASET: DatasetSpec = DatasetSpec::default();
 }
 
-#[derive(Eq, PartialEq, Ord, PartialOrd, Debug, Clone, Hash)]
+#[derive(Eq, PartialEq, Debug, Clone, Hash)]
 pub enum QueryVariants {
     Select {
         dataset: DatasetSpec,
         algebra: GraphPattern,
+        base_iri: Option<Iri<String>>,
     },
     Construct {
         construct: Vec<TriplePattern>,
         dataset: DatasetSpec,
         algebra: GraphPattern,
+        base_iri: Option<Iri<String>>,
     },
     Describe {
         dataset: DatasetSpec,
         algebra: GraphPattern,
+        base_iri: Option<Iri<String>>,
     },
     Ask {
         dataset: DatasetSpec,
         algebra: GraphPattern,
+        base_iri: Option<Iri<String>>,
     },
 }
 
 impl fmt::Display for QueryVariants {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            QueryVariants::Select { dataset, algebra } => write!(
-                f,
-                "{}",
-                SparqlGraphRootPattern {
-                    algebra: &algebra,
-                    dataset: &dataset
+            QueryVariants::Select {
+                dataset,
+                algebra,
+                base_iri,
+            } => {
+                if let Some(base_iri) = base_iri {
+                    writeln!(f, "BASE <{}>", base_iri)?;
                 }
-            ),
+                write!(
+                    f,
+                    "{}",
+                    SparqlGraphRootPattern {
+                        algebra: &algebra,
+                        dataset: &dataset
+                    }
+                )
+            }
             QueryVariants::Construct {
                 construct,
                 dataset,
                 algebra,
-            } => write!(
-                f,
-                "CONSTRUCT {{ {} }} {} WHERE {{ {} }}",
-                construct
-                    .iter()
-                    .map(|t| t.to_string())
-                    .collect::<Vec<String>>()
-                    .join(" . "),
-                dataset,
-                SparqlGraphRootPattern {
-                    algebra: &algebra,
-                    dataset: &EMPTY_DATASET
+                base_iri,
+            } => {
+                if let Some(base_iri) = base_iri {
+                    writeln!(f, "BASE <{}>", base_iri)?;
                 }
-            ),
-            QueryVariants::Describe { dataset, algebra } => write!(
-                f,
-                "DESCRIBE * {} WHERE {{ {} }}",
+                write!(
+                    f,
+                    "CONSTRUCT {{ {} }} {} WHERE {{ {} }}",
+                    construct
+                        .iter()
+                        .map(|t| t.to_string())
+                        .collect::<Vec<String>>()
+                        .join(" . "),
+                    dataset,
+                    SparqlGraphRootPattern {
+                        algebra: &algebra,
+                        dataset: &EMPTY_DATASET
+                    }
+                )
+            }
+            QueryVariants::Describe {
                 dataset,
-                SparqlGraphRootPattern {
-                    algebra: &algebra,
-                    dataset: &EMPTY_DATASET
+                algebra,
+                base_iri,
+            } => {
+                if let Some(base_iri) = base_iri {
+                    writeln!(f, "BASE <{}>", base_iri.as_str())?;
                 }
-            ),
-            QueryVariants::Ask { dataset, algebra } => write!(
-                f,
-                "ASK {} WHERE {{ {} }}",
+                write!(
+                    f,
+                    "DESCRIBE * {} WHERE {{ {} }}",
+                    dataset,
+                    SparqlGraphRootPattern {
+                        algebra: &algebra,
+                        dataset: &EMPTY_DATASET
+                    }
+                )
+            }
+            QueryVariants::Ask {
                 dataset,
-                SparqlGraphRootPattern {
-                    algebra: &algebra,
-                    dataset: &EMPTY_DATASET
+                algebra,
+                base_iri,
+            } => {
+                if let Some(base_iri) = base_iri {
+                    writeln!(f, "BASE <{}>", base_iri)?;
                 }
-            ),
+                write!(
+                    f,
+                    "ASK {} WHERE {{ {} }}",
+                    dataset,
+                    SparqlGraphRootPattern {
+                        algebra: &algebra,
+                        dataset: &EMPTY_DATASET
+                    }
+                )
+            }
         }
     }
 }
diff --git a/lib/src/sparql/eval.rs b/lib/src/sparql/eval.rs
index cd8e1a4d..72c730c5 100644
--- a/lib/src/sparql/eval.rs
+++ b/lib/src/sparql/eval.rs
@@ -2,23 +2,33 @@ use crate::model::BlankNode;
 use crate::model::Triple;
 use crate::sparql::model::*;
 use crate::sparql::plan::*;
-use crate::store::numeric_encoder::MemoryStringStore;
 use crate::store::numeric_encoder::*;
+use crate::store::numeric_encoder::{MemoryStringStore, ENCODED_EMPTY_STRING_LITERAL};
 use crate::store::StoreConnection;
 use crate::Result;
 use chrono::prelude::*;
+use digest::Digest;
+use md5::Md5;
 use num_traits::identities::Zero;
 use num_traits::FromPrimitive;
 use num_traits::One;
 use num_traits::ToPrimitive;
-use regex::RegexBuilder;
-use rust_decimal::Decimal;
+use rand::random;
+use regex::{Regex, RegexBuilder};
+use rio_api::iri::Iri;
+use rio_api::model as rio;
+use rust_decimal::{Decimal, RoundingStrategy};
+use sha1::Sha1;
+use sha2::{Sha256, Sha384, Sha512};
 use std::cmp::Ordering;
 use std::collections::BTreeMap;
 use std::collections::HashSet;
+use std::convert::TryInto;
+use std::fmt::Write;
 use std::iter::once;
 use std::iter::Iterator;
 use std::ops::Deref;
+use std::str;
 use std::sync::Arc;
 use std::sync::Mutex;
 use std::u64;
@@ -32,13 +42,17 @@ type EncodedTuplesIterator<'a> = Box<dyn Iterator<Item = Result<EncodedTuple>> +
 pub struct SimpleEvaluator<S: StoreConnection> {
     dataset: DatasetView<S>,
     bnodes_map: Arc<Mutex<BTreeMap<u64, Uuid>>>,
+    base_iri: Option<Arc<Iri<String>>>,
+    now: DateTime<FixedOffset>,
 }
 
 impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
-    pub fn new(dataset: S) -> Self {
+    pub fn new(dataset: S, base_iri: Option<Iri<String>>) -> Self {
         Self {
             dataset: DatasetView::new(dataset),
             bnodes_map: Arc::new(Mutex::new(BTreeMap::default())),
+            base_iri: base_iri.map(Arc::new),
+            now: Utc::now().with_timezone(&FixedOffset::east(0)),
         }
     }
 
@@ -412,25 +426,25 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
                 NumericBinaryOperands::Float(v1, v2) => (v1 + v2).into(),
                 NumericBinaryOperands::Double(v1, v2) => (v1 + v2).into(),
                 NumericBinaryOperands::Integer(v1, v2) => v1.checked_add(v2)?.into(),
-                NumericBinaryOperands::Decimal(v1, v2) => (v1 + v2).into(),
+                NumericBinaryOperands::Decimal(v1, v2) => v1.checked_add(v2)?.into(),
             }),
             PlanExpression::Sub(a, b) => Some(match self.parse_numeric_operands(a, b, tuple)? {
                 NumericBinaryOperands::Float(v1, v2) => (v1 - v2).into(),
                 NumericBinaryOperands::Double(v1, v2) => (v1 - v2).into(),
                 NumericBinaryOperands::Integer(v1, v2) => v1.checked_sub(v2)?.into(),
-                NumericBinaryOperands::Decimal(v1, v2) => (v1 - v2).into(),
+                NumericBinaryOperands::Decimal(v1, v2) => v1.checked_sub(v2)?.into(),
             }),
             PlanExpression::Mul(a, b) => Some(match self.parse_numeric_operands(a, b, tuple)? {
                 NumericBinaryOperands::Float(v1, v2) => (v1 * v2).into(),
                 NumericBinaryOperands::Double(v1, v2) => (v1 * v2).into(),
                 NumericBinaryOperands::Integer(v1, v2) => v1.checked_mul(v2)?.into(),
-                NumericBinaryOperands::Decimal(v1, v2) => (v1 * v2).into(),
+                NumericBinaryOperands::Decimal(v1, v2) => v1.checked_mul(v2)?.into(),
             }),
             PlanExpression::Div(a, b) => Some(match self.parse_numeric_operands(a, b, tuple)? {
                 NumericBinaryOperands::Float(v1, v2) => (v1 / v2).into(),
                 NumericBinaryOperands::Double(v1, v2) => (v1 / v2).into(),
                 NumericBinaryOperands::Integer(v1, v2) => v1.checked_div(v2)?.into(),
-                NumericBinaryOperands::Decimal(v1, v2) => (v1 / v2).into(),
+                NumericBinaryOperands::Decimal(v1, v2) => v1.checked_div(v2)?.into(),
             }),
             PlanExpression::UnaryPlus(e) => match self.eval_expression(e, tuple)? {
                 EncodedTerm::FloatLiteral(value) => Some((*value).into()),
@@ -461,29 +475,267 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
                 e if e.is_literal() => Some(ENCODED_EMPTY_STRING_LITERAL),
                 _ => None,
             },
+            PlanExpression::LangMatches(language_tag, language_range) => {
+                let language_tag =
+                    self.to_simple_string(self.eval_expression(language_tag, tuple)?)?;
+                let language_range =
+                    self.to_simple_string(self.eval_expression(language_range, tuple)?)?;
+                Some(
+                    if &*language_range == "*" {
+                        !language_tag.is_empty()
+                    } else {
+                        !ZipLongest::new(language_range.split('-'), language_tag.split('-')).any(
+                            |parts| match parts {
+                                (Some(range_subtag), Some(language_subtag)) => {
+                                    !range_subtag.eq_ignore_ascii_case(language_subtag)
+                                }
+                                (Some(_), None) => true,
+                                (None, _) => false,
+                            },
+                        )
+                    }
+                    .into(),
+                )
+            }
             PlanExpression::Datatype(e) => self.eval_expression(e, tuple)?.datatype(),
             PlanExpression::Bound(v) => Some(has_tuple_value(*v, tuple).into()),
-            PlanExpression::IRI(e) => match self.eval_expression(e, tuple)? {
-                EncodedTerm::NamedNode { iri_id } => Some(EncodedTerm::NamedNode { iri_id }),
-                EncodedTerm::StringLiteral { value_id } => {
-                    Some(EncodedTerm::NamedNode { iri_id: value_id })
+            PlanExpression::IRI(e) => {
+                let iri_id = match self.eval_expression(e, tuple)? {
+                    EncodedTerm::NamedNode { iri_id } => Some(iri_id),
+                    EncodedTerm::StringLiteral { value_id } => Some(value_id),
+                    _ => None,
+                }?;
+                let iri = self.dataset.get_str(iri_id).ok()??;
+                Some(if let Some(base_iri) = &self.base_iri {
+                    EncodedTerm::NamedNode {
+                        iri_id: self
+                            .dataset
+                            .insert_str(&base_iri.resolve(&iri).ok()?.into_inner())
+                            .ok()?,
+                    }
+                } else {
+                    Iri::parse(iri).ok()?;
+                    EncodedTerm::NamedNode { iri_id }
+                })
+            }
+            PlanExpression::BNode(id) => match id {
+                Some(id) => {
+                    if let EncodedTerm::StringLiteral { value_id } =
+                        self.eval_expression(id, tuple)?
+                    {
+                        Some(EncodedTerm::BlankNode(
+                            *self
+                                .bnodes_map
+                                .lock()
+                                .ok()?
+                                .entry(value_id)
+                                .or_insert_with(Uuid::new_v4),
+                        ))
+                    } else {
+                        None
+                    }
                 }
+                None => Some(EncodedTerm::BlankNode(Uuid::new_v4())),
+            },
+            PlanExpression::Rand => Some(random::<f64>().into()),
+            PlanExpression::Abs(e) => match self.eval_expression(e, tuple)? {
+                EncodedTerm::IntegerLiteral(value) => Some(value.checked_abs()?.into()),
+                EncodedTerm::DecimalLiteral(value) => Some(value.abs().into()),
+                EncodedTerm::FloatLiteral(value) => Some(value.abs().into()),
+                EncodedTerm::DoubleLiteral(value) => Some(value.abs().into()),
                 _ => None,
             },
-            PlanExpression::BNode(id) => match id {
-                Some(id) => match self.eval_expression(id, tuple)? {
-                    EncodedTerm::StringLiteral { value_id } => Some(EncodedTerm::BlankNode(
-                        *self
-                            .bnodes_map
-                            .lock()
-                            .ok()?
-                            .entry(value_id)
-                            .or_insert_with(Uuid::new_v4),
-                    )),
-                    _ => None,
-                },
-                None => Some(EncodedTerm::BlankNode(Uuid::new_v4())),
+            PlanExpression::Ceil(e) => match self.eval_expression(e, tuple)? {
+                EncodedTerm::IntegerLiteral(value) => Some(value.into()),
+                EncodedTerm::DecimalLiteral(value) => Some(value.ceil().into()),
+                EncodedTerm::FloatLiteral(value) => Some(value.ceil().into()),
+                EncodedTerm::DoubleLiteral(value) => Some(value.ceil().into()),
+                _ => None,
             },
+            PlanExpression::Floor(e) => match self.eval_expression(e, tuple)? {
+                EncodedTerm::IntegerLiteral(value) => Some(value.into()),
+                EncodedTerm::DecimalLiteral(value) => Some(value.floor().into()),
+                EncodedTerm::FloatLiteral(value) => Some(value.floor().into()),
+                EncodedTerm::DoubleLiteral(value) => Some(value.floor().into()),
+                _ => None,
+            },
+            PlanExpression::Round(e) => match self.eval_expression(e, tuple)? {
+                EncodedTerm::IntegerLiteral(value) => Some(value.into()),
+                EncodedTerm::DecimalLiteral(value) => Some(
+                    value
+                        .round_dp_with_strategy(0, RoundingStrategy::RoundHalfUp)
+                        .into(),
+                ),
+                EncodedTerm::FloatLiteral(value) => Some(value.round().into()),
+                EncodedTerm::DoubleLiteral(value) => Some(value.round().into()),
+                _ => None,
+            },
+            PlanExpression::Concat(l) => {
+                let mut result = String::default();
+                let mut language = None;
+                for e in l {
+                    let (value, e_language) =
+                        self.to_string_and_language(self.eval_expression(e, tuple)?)?;
+                    if let Some(lang) = language {
+                        if lang != e_language {
+                            language = Some(None)
+                        }
+                    } else {
+                        language = Some(e_language)
+                    }
+                    result += &value
+                }
+                self.build_plain_literal(&result, language.and_then(|v| v))
+            }
+            PlanExpression::SubStr(source, starting_loc, length) => {
+                let (source, language) =
+                    self.to_string_and_language(self.eval_expression(source, tuple)?)?;
+
+                let starting_location: usize = if let EncodedTerm::IntegerLiteral(v) =
+                    self.eval_expression(starting_loc, tuple)?
+                {
+                    v.try_into().ok()?
+                } else {
+                    return None;
+                };
+                let length: Option<usize> = if let Some(length) = length {
+                    if let EncodedTerm::IntegerLiteral(v) = self.eval_expression(length, tuple)? {
+                        Some(v.try_into().ok()?)
+                    } else {
+                        return None;
+                    }
+                } else {
+                    None
+                };
+
+                // We want to slice on char indices, not byte indices
+                let mut start_iter = source
+                    .char_indices()
+                    .skip(starting_location.checked_sub(1)?)
+                    .peekable();
+                let result = if let Some((start_position, _)) = start_iter.peek().cloned() {
+                    if let Some(length) = length {
+                        let mut end_iter = start_iter.skip(length).peekable();
+                        if let Some((end_position, _)) = end_iter.peek() {
+                            &source[start_position..*end_position]
+                        } else {
+                            &source[start_position..]
+                        }
+                    } else {
+                        &source[start_position..]
+                    }
+                } else {
+                    ""
+                };
+                self.build_plain_literal(result, language)
+            }
+            PlanExpression::StrLen(arg) => Some(
+                (self
+                    .to_string(self.eval_expression(arg, tuple)?)?
+                    .chars()
+                    .count() as i128)
+                    .into(),
+            ),
+            PlanExpression::Replace(arg, pattern, replacement, flags) => {
+                let regex = self.compile_pattern(
+                    self.eval_expression(pattern, tuple)?,
+                    if let Some(flags) = flags {
+                        Some(self.eval_expression(flags, tuple)?)
+                    } else {
+                        None
+                    },
+                )?;
+                let (text, language) =
+                    self.to_string_and_language(self.eval_expression(arg, tuple)?)?;
+                let replacement =
+                    self.to_simple_string(self.eval_expression(replacement, tuple)?)?;
+                self.build_plain_literal(&regex.replace_all(&text, &replacement as &str), language)
+            }
+            PlanExpression::UCase(e) => {
+                let (value, language) =
+                    self.to_string_and_language(self.eval_expression(e, tuple)?)?;
+                self.build_plain_literal(&value.to_uppercase(), language)
+            }
+            PlanExpression::LCase(e) => {
+                let (value, language) =
+                    self.to_string_and_language(self.eval_expression(e, tuple)?)?;
+                self.build_plain_literal(&value.to_lowercase(), language)
+            }
+            PlanExpression::StrStarts(arg1, arg2) => {
+                let (arg1, arg2, _) = self.to_argument_compatible_strings(
+                    self.eval_expression(arg1, tuple)?,
+                    self.eval_expression(arg2, tuple)?,
+                )?;
+                Some((&arg1).starts_with(&arg2 as &str).into())
+            }
+            PlanExpression::EncodeForURI(ltrl) => {
+                let ltlr = self.to_string(self.eval_expression(ltrl, tuple)?)?;
+                let mut result = Vec::with_capacity(ltlr.len());
+                for c in ltlr.bytes() {
+                    match c {
+                        b'A'..=b'Z' | b'a'..=b'z' | b'0'..=b'9' | b'-' | b'_' | b'.' | b'~' => {
+                            result.push(c)
+                        }
+                        _ => {
+                            result.push(b'%');
+                            let hight = c / 16;
+                            let low = c % 16;
+                            result.push(if hight < 10 {
+                                b'0' + hight
+                            } else {
+                                b'A' + (hight - 10)
+                            });
+                            result.push(if low < 10 {
+                                b'0' + low
+                            } else {
+                                b'A' + (low - 10)
+                            });
+                        }
+                    }
+                }
+                Some(EncodedTerm::StringLiteral {
+                    value_id: self
+                        .dataset
+                        .insert_str(str::from_utf8(&result).ok()?)
+                        .ok()?,
+                })
+            }
+            PlanExpression::StrEnds(arg1, arg2) => {
+                let (arg1, arg2, _) = self.to_argument_compatible_strings(
+                    self.eval_expression(arg1, tuple)?,
+                    self.eval_expression(arg2, tuple)?,
+                )?;
+                Some((&arg1).ends_with(&arg2 as &str).into())
+            }
+            PlanExpression::Contains(arg1, arg2) => {
+                let (arg1, arg2, _) = self.to_argument_compatible_strings(
+                    self.eval_expression(arg1, tuple)?,
+                    self.eval_expression(arg2, tuple)?,
+                )?;
+                Some((&arg1).contains(&arg2 as &str).into())
+            }
+            PlanExpression::StrBefore(arg1, arg2) => {
+                let (arg1, arg2, language) = self.to_argument_compatible_strings(
+                    self.eval_expression(arg1, tuple)?,
+                    self.eval_expression(arg2, tuple)?,
+                )?;
+                if let Some(position) = (&arg1).find(&arg2 as &str) {
+                    self.build_plain_literal(&arg1[..position], language)
+                } else {
+                    Some(ENCODED_EMPTY_STRING_LITERAL)
+                }
+            }
+            PlanExpression::StrAfter(arg1, arg2) => {
+                let (arg1, arg2, language) = self.to_argument_compatible_strings(
+                    self.eval_expression(arg1, tuple)?,
+                    self.eval_expression(arg2, tuple)?,
+                )?;
+                if let Some(position) = (&arg1).find(&arg2 as &str) {
+                    self.build_plain_literal(&arg1[position + arg2.len()..], language)
+                } else {
+                    Some(ENCODED_EMPTY_STRING_LITERAL)
+                }
+            }
             PlanExpression::Year(e) => match self.eval_expression(e, tuple)? {
                 EncodedTerm::DateLiteral(date) => Some(date.year().into()),
                 EncodedTerm::NaiveDateLiteral(date) => Some(date.year().into()),
@@ -518,23 +770,105 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
                 _ => None,
             },
             PlanExpression::Seconds(e) => match self.eval_expression(e, tuple)? {
-                EncodedTerm::NaiveTimeLiteral(time) => Some(time.second().into()),
-                EncodedTerm::DateTimeLiteral(date_time) => Some(date_time.second().into()),
-                EncodedTerm::NaiveDateTimeLiteral(date_time) => Some(date_time.second().into()),
+                EncodedTerm::NaiveTimeLiteral(time) => Some(
+                    (Decimal::new(time.nanosecond().into(), 9) + Decimal::from(time.second()))
+                        .into(),
+                ),
+                EncodedTerm::DateTimeLiteral(date_time) => Some(
+                    (Decimal::new(date_time.nanosecond().into(), 9)
+                        + Decimal::from(date_time.second()))
+                    .into(),
+                ),
+                EncodedTerm::NaiveDateTimeLiteral(date_time) => Some(
+                    (Decimal::new(date_time.nanosecond().into(), 9)
+                        + Decimal::from(date_time.second()))
+                    .into(),
+                ),
                 _ => None,
             },
-            PlanExpression::UUID() => Some(EncodedTerm::NamedNode {
+            PlanExpression::Timezone(e) => {
+                let timezone = match self.eval_expression(e, tuple)? {
+                    EncodedTerm::DateLiteral(date) => date.timezone(),
+                    EncodedTerm::DateTimeLiteral(date_time) => date_time.timezone(),
+                    _ => return None,
+                };
+                let mut result = String::with_capacity(9);
+                let mut shift = timezone.local_minus_utc();
+                if shift < 0 {
+                    write!(&mut result, "-").ok()?;
+                    shift = -shift
+                };
+                write!(&mut result, "PT").ok()?;
+
+                let hours = shift / 3600;
+                if hours > 0 {
+                    write!(&mut result, "{}H", hours).ok()?;
+                }
+
+                let minutes = (shift / 60) % 60;
+                if minutes > 0 {
+                    write!(&mut result, "{}M", minutes).ok()?;
+                }
+
+                let seconds = shift % 60;
+                if seconds > 0 || shift == 0 {
+                    write!(&mut result, "{}S", seconds).ok()?;
+                }
+                Some(EncodedTerm::TypedLiteral {
+                    value_id: self.dataset.insert_str(&result).ok()?,
+                    datatype_id: self
+                        .dataset
+                        .insert_str("http://www.w3.org/2001/XMLSchema#dayTimeDuration")
+                        .ok()?,
+                })
+            }
+            PlanExpression::Tz(e) => {
+                let timezone = match self.eval_expression(e, tuple)? {
+                    EncodedTerm::DateLiteral(date) => Some(date.timezone()),
+                    EncodedTerm::DateTimeLiteral(date_time) => Some(date_time.timezone()),
+                    EncodedTerm::NaiveDateLiteral(_)
+                    | EncodedTerm::NaiveTimeLiteral(_)
+                    | EncodedTerm::NaiveDateTimeLiteral(_) => None,
+                    _ => return None,
+                };
+                Some(if let Some(timezone) = timezone {
+                    EncodedTerm::StringLiteral {
+                        value_id: if timezone.local_minus_utc() == 0 {
+                            self.dataset.insert_str("Z").ok()?
+                        } else {
+                            self.dataset.insert_str(&timezone.to_string()).ok()?
+                        },
+                    }
+                } else {
+                    ENCODED_EMPTY_STRING_LITERAL
+                })
+            }
+            PlanExpression::Now => Some(self.now.into()),
+            PlanExpression::UUID => Some(EncodedTerm::NamedNode {
                 iri_id: self
                     .dataset
-                    .insert_str(&Uuid::new_v4().to_urn().to_string())
+                    .insert_str(
+                        Uuid::new_v4()
+                            .to_urn()
+                            .encode_lower(&mut Uuid::encode_buffer()),
+                    )
                     .ok()?,
             }),
-            PlanExpression::StrUUID() => Some(EncodedTerm::StringLiteral {
+            PlanExpression::StrUUID => Some(EncodedTerm::StringLiteral {
                 value_id: self
                     .dataset
-                    .insert_str(&Uuid::new_v4().to_simple().to_string())
+                    .insert_str(
+                        Uuid::new_v4()
+                            .to_hyphenated()
+                            .encode_lower(&mut Uuid::encode_buffer()),
+                    )
                     .ok()?,
             }),
+            PlanExpression::MD5(arg) => self.hash::<Md5>(arg, tuple),
+            PlanExpression::SHA1(arg) => self.hash::<Sha1>(arg, tuple),
+            PlanExpression::SHA256(arg) => self.hash::<Sha256>(arg, tuple),
+            PlanExpression::SHA384(arg) => self.hash::<Sha384>(arg, tuple),
+            PlanExpression::SHA512(arg) => self.hash::<Sha512>(arg, tuple),
             PlanExpression::Coalesce(l) => {
                 for e in l {
                     if let Some(result) = self.eval_expression(e, tuple) {
@@ -558,6 +892,23 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
                         .to_simple_string_id(self.eval_expression(lang_tag, tuple)?)?,
                 })
             }
+            PlanExpression::StrDT(lexical_form, datatype) => {
+                let value = self.to_simple_string(self.eval_expression(lexical_form, tuple)?)?;
+                let datatype = if let EncodedTerm::NamedNode { iri_id } =
+                    self.eval_expression(datatype, tuple)?
+                {
+                    self.dataset.get_str(iri_id).ok()?
+                } else {
+                    None
+                }?;
+                self.dataset
+                    .encoder()
+                    .encode_rio_literal(rio::Literal::Typed {
+                        value: &value,
+                        datatype: rio::NamedNode { iri: &datatype },
+                    })
+                    .ok()
+            }
             PlanExpression::SameTerm(a, b) => {
                 Some((self.eval_expression(a, tuple)? == self.eval_expression(b, tuple)?).into())
             }
@@ -580,55 +931,15 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
                 }
                 .into(),
             ),
-            PlanExpression::LangMatches(language_tag, language_range) => {
-                let language_tag =
-                    self.to_simple_string(self.eval_expression(language_tag, tuple)?)?;
-                let language_range =
-                    self.to_simple_string(self.eval_expression(language_range, tuple)?)?;
-                Some(
-                    if &*language_range == "*" {
-                        !language_tag.is_empty()
-                    } else {
-                        !ZipLongest::new(language_range.split('-'), language_tag.split('-')).any(
-                            |parts| match parts {
-                                (Some(range_subtag), Some(language_subtag)) => {
-                                    !range_subtag.eq_ignore_ascii_case(language_subtag)
-                                }
-                                (Some(_), None) => true,
-                                (None, _) => false,
-                            },
-                        )
-                    }
-                    .into(),
-                )
-            }
             PlanExpression::Regex(text, pattern, flags) => {
-                // TODO Avoid to compile the regex each time
-                let pattern = self.to_simple_string(self.eval_expression(pattern, tuple)?)?;
-                let mut regex_builder = RegexBuilder::new(&pattern);
-                regex_builder.size_limit(REGEX_SIZE_LIMIT);
-                if let Some(flags) = flags {
-                    let flags = self.to_simple_string(self.eval_expression(flags, tuple)?)?;
-                    for flag in flags.chars() {
-                        match flag {
-                            's' => {
-                                regex_builder.dot_matches_new_line(true);
-                            }
-                            'm' => {
-                                regex_builder.multi_line(true);
-                            }
-                            'i' => {
-                                regex_builder.case_insensitive(true);
-                            }
-                            'x' => {
-                                regex_builder.ignore_whitespace(true);
-                            }
-                            'q' => (), //TODO: implement
-                            _ => (),
-                        }
-                    }
-                }
-                let regex = regex_builder.build().ok()?;
+                let regex = self.compile_pattern(
+                    self.eval_expression(pattern, tuple)?,
+                    if let Some(flags) = flags {
+                        Some(self.eval_expression(flags, tuple)?)
+                    } else {
+                        None
+                    },
+                )?;
                 let text = self.to_string(self.eval_expression(text, tuple)?)?;
                 Some(regex.is_match(&text).into())
             }
@@ -806,6 +1117,82 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
         }
     }
 
+    fn to_string_and_language(
+        &self,
+        term: EncodedTerm,
+    ) -> Option<(<DatasetView<S> as StringStore>::StringType, Option<u64>)> {
+        match term {
+            EncodedTerm::StringLiteral { value_id } => {
+                Some((self.dataset.get_str(value_id).ok()??, None))
+            }
+            EncodedTerm::LangStringLiteral {
+                value_id,
+                language_id,
+            } => Some((self.dataset.get_str(value_id).ok()??, Some(language_id))),
+            _ => None,
+        }
+    }
+
+    fn build_plain_literal(&self, value: &str, language: Option<u64>) -> Option<EncodedTerm> {
+        Some(if let Some(language_id) = language {
+            EncodedTerm::LangStringLiteral {
+                value_id: self.dataset.insert_str(value).ok()?,
+                language_id,
+            }
+        } else {
+            EncodedTerm::StringLiteral {
+                value_id: self.dataset.insert_str(value).ok()?,
+            }
+        })
+    }
+
+    fn to_argument_compatible_strings(
+        &self,
+        arg1: EncodedTerm,
+        arg2: EncodedTerm,
+    ) -> Option<(
+        <DatasetView<S> as StringStore>::StringType,
+        <DatasetView<S> as StringStore>::StringType,
+        Option<u64>,
+    )> {
+        let (value1, language1) = self.to_string_and_language(arg1)?;
+        let (value2, language2) = self.to_string_and_language(arg2)?;
+        if language2.is_none() || language1 == language2 {
+            Some((value1, value2, language1))
+        } else {
+            None
+        }
+    }
+
+    fn compile_pattern(&self, pattern: EncodedTerm, flags: Option<EncodedTerm>) -> Option<Regex> {
+        // TODO Avoid to compile the regex each time
+        let pattern = self.to_simple_string(pattern)?;
+        let mut regex_builder = RegexBuilder::new(&pattern);
+        regex_builder.size_limit(REGEX_SIZE_LIMIT);
+        if let Some(flags) = flags {
+            let flags = self.to_simple_string(flags)?;
+            for flag in flags.chars() {
+                match flag {
+                    's' => {
+                        regex_builder.dot_matches_new_line(true);
+                    }
+                    'm' => {
+                        regex_builder.multi_line(true);
+                    }
+                    'i' => {
+                        regex_builder.case_insensitive(true);
+                    }
+                    'x' => {
+                        regex_builder.ignore_whitespace(true);
+                    }
+                    'q' => (), //TODO: implement
+                    _ => (),
+                }
+            }
+        }
+        regex_builder.build().ok()
+    }
+
     fn parse_numeric_operands(
         &self,
         e1: &PlanExpression,
@@ -1118,6 +1505,18 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
                 .cmp(&self.dataset.get_str(b).ok()??),
         )
     }
+
+    fn hash<H: Digest>(
+        &self,
+        arg: &PlanExpression,
+        tuple: &[Option<EncodedTerm>],
+    ) -> Option<EncodedTerm> {
+        let input = self.to_simple_string(self.eval_expression(arg, tuple)?)?;
+        let hash = hex::encode(H::new().chain(&input as &str).result());
+        Some(EncodedTerm::StringLiteral {
+            value_id: self.dataset.insert_str(&hash).ok()?,
+        })
+    }
 }
 
 #[derive(Clone)]
diff --git a/lib/src/sparql/mod.rs b/lib/src/sparql/mod.rs
index 6632a997..093b4e66 100644
--- a/lib/src/sparql/mod.rs
+++ b/lib/src/sparql/mod.rs
@@ -60,28 +60,31 @@ impl<S: StoreConnection> SimplePreparedQuery<S> {
             QueryVariants::Select {
                 algebra,
                 dataset: _,
+                base_iri,
             } => {
                 let (plan, variables) = PlanBuilder::build(&connection, &algebra)?;
                 SimplePreparedQueryOptions::Select {
                     plan,
                     variables,
-                    evaluator: SimpleEvaluator::new(connection),
+                    evaluator: SimpleEvaluator::new(connection, base_iri),
                 }
             }
             QueryVariants::Ask {
                 algebra,
                 dataset: _,
+                base_iri,
             } => {
                 let (plan, _) = PlanBuilder::build(&connection, &algebra)?;
                 SimplePreparedQueryOptions::Ask {
                     plan,
-                    evaluator: SimpleEvaluator::new(connection),
+                    evaluator: SimpleEvaluator::new(connection, base_iri),
                 }
             }
             QueryVariants::Construct {
                 construct,
                 algebra,
                 dataset: _,
+                base_iri,
             } => {
                 let (plan, variables) = PlanBuilder::build(&connection, &algebra)?;
                 SimplePreparedQueryOptions::Construct {
@@ -91,17 +94,18 @@ impl<S: StoreConnection> SimplePreparedQuery<S> {
                         &construct,
                         variables,
                     )?,
-                    evaluator: SimpleEvaluator::new(connection),
+                    evaluator: SimpleEvaluator::new(connection, base_iri),
                 }
             }
             QueryVariants::Describe {
                 algebra,
                 dataset: _,
+                base_iri,
             } => {
                 let (plan, _) = PlanBuilder::build(&connection, &algebra)?;
                 SimplePreparedQueryOptions::Describe {
                     plan,
-                    evaluator: SimpleEvaluator::new(connection),
+                    evaluator: SimpleEvaluator::new(connection, base_iri),
                 }
             }
         }))
@@ -132,7 +136,7 @@ impl<S: StoreConnection> PreparedQuery for SimplePreparedQuery<S> {
 }
 
 /// A parsed [SPARQL query](https://www.w3.org/TR/sparql11-query/)
-#[derive(Eq, PartialEq, Ord, PartialOrd, Debug, Clone, Hash)]
+#[derive(Eq, PartialEq, Debug, Clone, Hash)]
 pub struct Query(QueryVariants);
 
 impl fmt::Display for Query {
diff --git a/lib/src/sparql/plan.rs b/lib/src/sparql/plan.rs
index fabfc7f4..91ff9ea9 100644
--- a/lib/src/sparql/plan.rs
+++ b/lib/src/sparql/plan.rs
@@ -179,13 +179,17 @@ pub enum PlanExpression {
     Bound(usize),
     IRI(Box<PlanExpression>),
     BNode(Option<Box<PlanExpression>>),
-    /*Rand(),
+    Rand,
     Abs(Box<PlanExpression>),
     Ceil(Box<PlanExpression>),
     Floor(Box<PlanExpression>),
     Round(Box<PlanExpression>),
     Concat(Vec<PlanExpression>),
-    SubStr(Box<PlanExpression>, Box<PlanExpression>, Option<Box<PlanExpression>>),
+    SubStr(
+        Box<PlanExpression>,
+        Box<PlanExpression>,
+        Option<Box<PlanExpression>>,
+    ),
     StrLen(Box<PlanExpression>),
     Replace(
         Box<PlanExpression>,
@@ -200,23 +204,23 @@ pub enum PlanExpression {
     StrStarts(Box<PlanExpression>, Box<PlanExpression>),
     StrEnds(Box<PlanExpression>, Box<PlanExpression>),
     StrBefore(Box<PlanExpression>, Box<PlanExpression>),
-    StrAfter(Box<PlanExpression>, Box<PlanExpression>),*/
+    StrAfter(Box<PlanExpression>, Box<PlanExpression>),
     Year(Box<PlanExpression>),
     Month(Box<PlanExpression>),
     Day(Box<PlanExpression>),
     Hours(Box<PlanExpression>),
     Minutes(Box<PlanExpression>),
     Seconds(Box<PlanExpression>),
-    /*Timezone(Box<PlanExpression>),
+    Timezone(Box<PlanExpression>),
     Tz(Box<PlanExpression>),
-    Now(),*/
-    UUID(),
-    StrUUID(),
-    /*MD5(Box<PlanExpression>),
+    Now,
+    UUID,
+    StrUUID,
+    MD5(Box<PlanExpression>),
     SHA1(Box<PlanExpression>),
     SHA256(Box<PlanExpression>),
     SHA384(Box<PlanExpression>),
-    SHA512(Box<PlanExpression>),*/
+    SHA512(Box<PlanExpression>),
     Coalesce(Vec<PlanExpression>),
     If(
         Box<PlanExpression>,
@@ -224,7 +228,7 @@ pub enum PlanExpression {
         Box<PlanExpression>,
     ),
     StrLang(Box<PlanExpression>, Box<PlanExpression>),
-    //StrDT(Box<PlanExpression>, Box<PlanExpression>),
+    StrDT(Box<PlanExpression>, Box<PlanExpression>),
     SameTerm(Box<PlanExpression>, Box<PlanExpression>),
     IsIRI(Box<PlanExpression>),
     IsBlank(Box<PlanExpression>),
@@ -251,30 +255,13 @@ impl PlanExpression {
         match self {
             PlanExpression::Constant(_)
             | PlanExpression::BNode(None)
-            | PlanExpression::UUID()
-            | PlanExpression::StrUUID() => (),
+            | PlanExpression::UUID
+            | PlanExpression::StrUUID
+            | PlanExpression::Rand
+            | PlanExpression::Now => (),
             PlanExpression::Variable(v) | PlanExpression::Bound(v) => {
                 set.insert(*v);
             }
-            PlanExpression::Or(a, b)
-            | PlanExpression::And(a, b)
-            | PlanExpression::Equal(a, b)
-            | PlanExpression::NotEqual(a, b)
-            | PlanExpression::Greater(a, b)
-            | PlanExpression::GreaterOrEq(a, b)
-            | PlanExpression::Lower(a, b)
-            | PlanExpression::LowerOrEq(a, b)
-            | PlanExpression::Add(a, b)
-            | PlanExpression::Sub(a, b)
-            | PlanExpression::Mul(a, b)
-            | PlanExpression::Div(a, b)
-            | PlanExpression::SameTerm(a, b)
-            | PlanExpression::LangMatches(a, b)
-            | PlanExpression::StrLang(a, b)
-            | PlanExpression::Regex(a, b, None) => {
-                a.add_variables(set);
-                b.add_variables(set);
-            }
             PlanExpression::UnaryPlus(e)
             | PlanExpression::UnaryMinus(e)
             | PlanExpression::UnaryNot(e)
@@ -301,23 +288,68 @@ impl PlanExpression {
             | PlanExpression::DateCast(e)
             | PlanExpression::TimeCast(e)
             | PlanExpression::DateTimeCast(e)
-            | PlanExpression::StringCast(e) => {
+            | PlanExpression::StringCast(e)
+            | PlanExpression::Abs(e)
+            | PlanExpression::Ceil(e)
+            | PlanExpression::Floor(e)
+            | PlanExpression::Round(e)
+            | PlanExpression::StrLen(e)
+            | PlanExpression::UCase(e)
+            | PlanExpression::LCase(e)
+            | PlanExpression::EncodeForURI(e)
+            | PlanExpression::Timezone(e)
+            | PlanExpression::Tz(e)
+            | PlanExpression::MD5(e)
+            | PlanExpression::SHA1(e)
+            | PlanExpression::SHA256(e)
+            | PlanExpression::SHA384(e)
+            | PlanExpression::SHA512(e) => {
                 e.add_variables(set);
             }
-            PlanExpression::Coalesce(l) => {
-                for e in l {
-                    e.add_variables(set);
-                }
+            PlanExpression::Or(a, b)
+            | PlanExpression::And(a, b)
+            | PlanExpression::Equal(a, b)
+            | PlanExpression::NotEqual(a, b)
+            | PlanExpression::Greater(a, b)
+            | PlanExpression::GreaterOrEq(a, b)
+            | PlanExpression::Lower(a, b)
+            | PlanExpression::LowerOrEq(a, b)
+            | PlanExpression::Add(a, b)
+            | PlanExpression::Sub(a, b)
+            | PlanExpression::Mul(a, b)
+            | PlanExpression::Div(a, b)
+            | PlanExpression::SameTerm(a, b)
+            | PlanExpression::LangMatches(a, b)
+            | PlanExpression::StrLang(a, b)
+            | PlanExpression::Contains(a, b)
+            | PlanExpression::StrStarts(a, b)
+            | PlanExpression::StrEnds(a, b)
+            | PlanExpression::StrBefore(a, b)
+            | PlanExpression::StrAfter(a, b)
+            | PlanExpression::StrDT(a, b)
+            | PlanExpression::Regex(a, b, None)
+            | PlanExpression::SubStr(a, b, None) => {
+                a.add_variables(set);
+                b.add_variables(set);
             }
-            PlanExpression::If(a, b, c) => {
+            PlanExpression::If(a, b, c)
+            | PlanExpression::SubStr(a, b, Some(c))
+            | PlanExpression::Replace(a, b, c, None)
+            | PlanExpression::Regex(a, b, Some(c)) => {
                 a.add_variables(set);
                 b.add_variables(set);
                 c.add_variables(set);
             }
-            PlanExpression::Regex(a, b, Some(c)) => {
+            PlanExpression::Replace(a, b, c, Some(d)) => {
                 a.add_variables(set);
                 b.add_variables(set);
                 c.add_variables(set);
+                d.add_variables(set);
+            }
+            PlanExpression::Coalesce(l) | PlanExpression::Concat(l) => {
+                for e in l {
+                    e.add_variables(set);
+                }
             }
             PlanExpression::In(e, l) => {
                 e.add_variables(set);
diff --git a/lib/src/sparql/plan_builder.rs b/lib/src/sparql/plan_builder.rs
index eef48bb7..64841fd6 100644
--- a/lib/src/sparql/plan_builder.rs
+++ b/lib/src/sparql/plan_builder.rs
@@ -305,6 +305,91 @@ impl<'a, S: StoreConnection> PlanBuilder<'a, S> {
                     )),
                     None => None,
                 }),
+                Function::Rand => PlanExpression::Rand,
+                Function::Abs => PlanExpression::Abs(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::Ceil => PlanExpression::Ceil(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::Floor => PlanExpression::Floor(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::Round => PlanExpression::Round(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::Concat => PlanExpression::Concat(self.expression_list(
+                    &parameters,
+                    variables,
+                    graph_name,
+                )?),
+                Function::SubStr => PlanExpression::SubStr(
+                    Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
+                    Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
+                    match parameters.get(2) {
+                        Some(flags) => Some(Box::new(
+                            self.build_for_expression(flags, variables, graph_name)?,
+                        )),
+                        None => None,
+                    },
+                ),
+                Function::StrLen => PlanExpression::StrLen(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::Replace => PlanExpression::Replace(
+                    Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
+                    Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
+                    Box::new(self.build_for_expression(&parameters[2], variables, graph_name)?),
+                    match parameters.get(3) {
+                        Some(flags) => Some(Box::new(
+                            self.build_for_expression(flags, variables, graph_name)?,
+                        )),
+                        None => None,
+                    },
+                ),
+                Function::UCase => PlanExpression::UCase(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::LCase => PlanExpression::LCase(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::EncodeForURI => PlanExpression::EncodeForURI(Box::new(
+                    self.build_for_expression(&parameters[0], variables, graph_name)?,
+                )),
+                Function::Contains => PlanExpression::Contains(
+                    Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
+                    Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
+                ),
+                Function::StrStarts => PlanExpression::StrStarts(
+                    Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
+                    Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
+                ),
+                Function::StrEnds => PlanExpression::StrEnds(
+                    Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
+                    Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
+                ),
+                Function::StrBefore => PlanExpression::StrBefore(
+                    Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
+                    Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
+                ),
+                Function::StrAfter => PlanExpression::StrAfter(
+                    Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
+                    Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
+                ),
                 Function::Year => PlanExpression::Year(Box::new(self.build_for_expression(
                     &parameters[0],
                     variables,
@@ -335,8 +420,42 @@ impl<'a, S: StoreConnection> PlanBuilder<'a, S> {
                     variables,
                     graph_name,
                 )?)),
-                Function::UUID => PlanExpression::UUID(),
-                Function::StrUUID => PlanExpression::StrUUID(),
+                Function::Timezone => PlanExpression::Timezone(Box::new(
+                    self.build_for_expression(&parameters[0], variables, graph_name)?,
+                )),
+                Function::Tz => PlanExpression::Tz(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::Now => PlanExpression::Now,
+                Function::UUID => PlanExpression::UUID,
+                Function::StrUUID => PlanExpression::StrUUID,
+                Function::MD5 => PlanExpression::MD5(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::SHA1 => PlanExpression::SHA1(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::SHA256 => PlanExpression::SHA256(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::SHA384 => PlanExpression::SHA384(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
+                Function::SHA512 => PlanExpression::SHA512(Box::new(self.build_for_expression(
+                    &parameters[0],
+                    variables,
+                    graph_name,
+                )?)),
                 Function::Coalesce => PlanExpression::Coalesce(self.expression_list(
                     &parameters,
                     variables,
@@ -351,6 +470,10 @@ impl<'a, S: StoreConnection> PlanBuilder<'a, S> {
                     Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
                     Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
                 ),
+                Function::StrDT => PlanExpression::StrDT(
+                    Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
+                    Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
+                ),
                 Function::SameTerm => PlanExpression::SameTerm(
                     Box::new(self.build_for_expression(&parameters[0], variables, graph_name)?),
                     Box::new(self.build_for_expression(&parameters[1], variables, graph_name)?),
@@ -458,7 +581,6 @@ impl<'a, S: StoreConnection> PlanBuilder<'a, S> {
                         Err(format_err!("Not supported custom function {}", expression))?
                     }
                 }
-                _ => unimplemented!(),
             },
             Expression::Bound(v) => PlanExpression::Bound(variable_key(variables, v)),
             Expression::Exists(n) => PlanExpression::Exists(Box::new(
diff --git a/lib/src/sparql/sparql_grammar.rustpeg b/lib/src/sparql/sparql_grammar.rustpeg
index 18c42051..c7ef6294 100644
--- a/lib/src/sparql/sparql_grammar.rustpeg
+++ b/lib/src/sparql/sparql_grammar.rustpeg
@@ -32,7 +32,8 @@ PrefixDecl -> () = "PREFIX"i _ ns:PNAME_NS _ i:IRIREF {
 SelectQuery -> QueryVariants = s:SelectClause _ d:DatasetClauses _ w:WhereClause _ g:GroupClause? _ h:HavingClause? _ o:OrderClause? _ l:LimitOffsetClauses? _ v:ValuesClause {  //TODO: Modifier
     QueryVariants::Select {
         dataset: d,
-        algebra: build_select(s, w, g, h, o, l, v, state)
+        algebra: build_select(s, w, g, h, o, l, v, state),
+        base_iri: state.base_iri.clone()
     }
 }
 
@@ -65,7 +66,8 @@ ConstructQuery -> QueryVariants =
         QueryVariants::Construct {
             construct: c,
             dataset: d,
-            algebra: build_select(Selection::default(), w, g, h, o, l, v, state)
+            algebra: build_select(Selection::default(), w, g, h, o, l, v, state),
+            base_iri: state.base_iri.clone()
         }
     } /
     "CONSTRUCT"i _ d:DatasetClauses _ "WHERE"i _ '{' _ c:ConstructQuery_optional_triple_template _ '}' _ g:GroupClause? _ h:HavingClause? _ o:OrderClause? _ l:LimitOffsetClauses? _ v:ValuesClause {
@@ -76,7 +78,8 @@ ConstructQuery -> QueryVariants =
                 Selection::default(),
                 GraphPattern::BGP(c.into_iter().map(TripleOrPathPattern::from).collect()),
                 g, h, o, l, v, state
-            )
+            ),
+            base_iri: state.base_iri.clone()
         }
     }
 
@@ -87,7 +90,8 @@ DescribeQuery -> QueryVariants =
     "DESCRIBE"i _ '*' _ d:DatasetClauses w:WhereClause? _ g:GroupClause? _ h:HavingClause? _ o:OrderClause? _ l:LimitOffsetClauses? _ v:ValuesClause {
         QueryVariants::Describe {
             dataset: d,
-            algebra: build_select(Selection::default(), w.unwrap_or_else(GraphPattern::default), g, h, o, l, v, state)
+            algebra: build_select(Selection::default(), w.unwrap_or_else(GraphPattern::default), g, h, o, l, v, state),
+            base_iri: state.base_iri.clone()
         }
     } /
     "DESCRIBE"i _ p:DescribeQuery_item+ _ d:DatasetClauses w:WhereClause? _ g:GroupClause? _ h:HavingClause? _ o:OrderClause? _ l:LimitOffsetClauses? _ v:ValuesClause {
@@ -99,7 +103,8 @@ DescribeQuery -> QueryVariants =
                     NamedNodeOrVariable::NamedNode(n) => SelectionMember::Expression(n.into(), Variable::default()),
                     NamedNodeOrVariable::Variable(v) => SelectionMember::Variable(v)
                 }).collect())
-            }, w.unwrap_or_else(GraphPattern::default), g, h, o, l, v, state)
+            }, w.unwrap_or_else(GraphPattern::default), g, h, o, l, v, state),
+            base_iri: state.base_iri.clone()
         }
     }
 DescribeQuery_item -> NamedNodeOrVariable = i:VarOrIri _ { i }
@@ -108,7 +113,8 @@ DescribeQuery_item -> NamedNodeOrVariable = i:VarOrIri _ { i }
 AskQuery -> QueryVariants = "ASK"i _ d:DatasetClauses w:WhereClause _ g:GroupClause? _ h:HavingClause? _ o:OrderClause? _ l:LimitOffsetClauses? _ v:ValuesClause {
     QueryVariants::Ask {
         dataset: d,
-        algebra: build_select(Selection::default(), w, g, h, o, l, v, state)
+        algebra: build_select(Selection::default(), w, g, h, o, l, v, state),
+        base_iri: state.base_iri.clone()
     }
 }
 
diff --git a/lib/src/sparql/xml_results.rs b/lib/src/sparql/xml_results.rs
index 3106cb18..bc3cecc6 100644
--- a/lib/src/sparql/xml_results.rs
+++ b/lib/src/sparql/xml_results.rs
@@ -154,10 +154,18 @@ pub fn read_xml_results<'a>(source: impl BufRead + 'a) -> Result<QueryResult<'a>
                         return Err(format_err!("Expecting <head> tag, found {}", reader.decode(event.name())?));
                     }
                 }
-                State::Head => if event.name() == b"variable" || event.name() == b"link" {
-                    return Err(format_err!("<variable> and <link> tag should be autoclosing"));
-                } else {
-                    return Err(format_err!("Expecting <variable> or <link> tag, found {}", reader.decode(event.name())?));
+                State::Head => {
+                    if event.name() == b"variable" {
+                        let name = event.attributes()
+                            .filter_map(|attr| attr.ok())
+                            .find(|attr| attr.key == b"name")
+                            .ok_or_else(|| format_err!("No name attribute found for the <variable> tag"))?;
+                        variables.push(name.unescape_and_decode_value(&reader)?);
+                    } else if event.name() == b"link" {
+                        // no op
+                    } else {
+                        return Err(format_err!("Expecting <variable> or <link> tag, found {}", reader.decode(event.name())?));
+                    }
                 }
                 State::AfterHead => {
                     if event.name() == b"boolean" {
@@ -184,6 +192,13 @@ pub fn read_xml_results<'a>(source: impl BufRead + 'a) -> Result<QueryResult<'a>
                 State::Boolean => return Err(format_err!("Unexpected tag inside of <boolean> tag: {}", reader.decode(event.name())?))
             },
             Event::Empty(event) => match state {
+                State::Sparql => {
+                    if event.name() == b"head" {
+                        state = State::AfterHead;
+                    } else {
+                        return Err(format_err!("Expecting <head> tag, found {}", reader.decode(event.name())?));
+                    }
+                }
                 State::Head => {
                     if event.name() == b"variable" {
                         let name = event.attributes()
@@ -366,7 +381,12 @@ impl<R: BufRead> ResultsIterator<R> {
                         }
                         State::Literal => {
                             term = Some(
-                                build_literal(self.reader.decode(&data)?, &lang, &datatype).into(),
+                                build_literal(
+                                    self.reader.decode(&data)?,
+                                    lang.take(),
+                                    datatype.take(),
+                                )
+                                .into(),
                             );
                         }
                         _ => {
@@ -400,7 +420,7 @@ impl<R: BufRead> ResultsIterator<R> {
                     State::Literal => {
                         if term.is_none() {
                             //We default to the empty literal
-                            term = Some(build_literal("", &lang, &datatype).into())
+                            term = Some(build_literal("", lang.take(), datatype.take()).into())
                         }
                         state = State::Binding;
                     }
@@ -415,13 +435,13 @@ impl<R: BufRead> ResultsIterator<R> {
 
 fn build_literal(
     value: impl Into<String>,
-    lang: &Option<String>,
-    datatype: &Option<NamedNode>,
+    lang: Option<String>,
+    datatype: Option<NamedNode>,
 ) -> Literal {
     match datatype {
-        Some(datatype) => Literal::new_typed_literal(value, datatype.clone()),
+        Some(datatype) => Literal::new_typed_literal(value, datatype),
         None => match lang {
-            Some(lang) => Literal::new_language_tagged_literal(value, lang.clone()),
+            Some(lang) => Literal::new_language_tagged_literal(value, lang),
             None => Literal::new_simple_literal(value),
         },
     }
diff --git a/lib/tests/sparql_test_cases.rs b/lib/tests/sparql_test_cases.rs
index 1b789f04..af3a91f8 100644
--- a/lib/tests/sparql_test_cases.rs
+++ b/lib/tests/sparql_test_cases.rs
@@ -89,6 +89,7 @@ fn sparql_w3c_query_evaluation_testsuite() -> Result<()> {
         "http://www.w3.org/2009/sparql/docs/tests/data-sparql11/bind/manifest.ttl",
         "http://www.w3.org/2009/sparql/docs/tests/data-sparql11/construct/manifest.ttl",
         "http://www.w3.org/2009/sparql/docs/tests/data-sparql11/exists/manifest.ttl",
+        "http://www.w3.org/2009/sparql/docs/tests/data-sparql11/functions/manifest.ttl",
     ];
 
     let test_blacklist = vec![
@@ -116,6 +117,10 @@ fn sparql_w3c_query_evaluation_testsuite() -> Result<()> {
         NamedNode::parse("http://www.w3.org/2001/sw/DataAccess/tests/data-r2/expr-builtin/manifest#dawg-datatype-2").unwrap(),
         // FROM support
         NamedNode::parse("http://www.w3.org/2009/sparql/docs/tests/data-sparql11/construct/manifest#constructwhere04").unwrap(),
+        //BNODE() scope is currently wrong
+        NamedNode::parse("http://www.w3.org/2009/sparql/docs/tests/data-sparql11/functions/manifest#bnode01").unwrap(),
+        //Decimal precision problem
+        NamedNode::parse("http://www.w3.org/2009/sparql/docs/tests/data-sparql11/functions/manifest#coalesce01").unwrap(),
     ];
 
     let mut failed = Vec::default();
@@ -211,7 +216,9 @@ fn load_graph_to_repository(
     connection: &<&MemoryRepository as Repository>::Connection,
     to_graph_name: Option<&NamedOrBlankNode>,
 ) -> Result<()> {
-    let syntax = if url.ends_with(".ttl") {
+    let syntax = if url.ends_with(".nt") {
+        GraphSyntax::NTriples
+    } else if url.ends_with(".ttl") {
         GraphSyntax::Turtle
     } else if url.ends_with(".rdf") {
         GraphSyntax::RdfXml