WIP: Makes clippy happy

Temporarily drops the join reordering code

.github/workflows/tests.yml

@@ -35,6 +35,8 @@ jobs:
         working-directory: ./lib/sparesults
       - run: cargo clippy
         working-directory: ./lib/spargebra
+      - run: cargo clippy
+        working-directory: ./lib/sparopt
       - run: cargo clippy --all-targets --all-features
 
   clippy_wasm_js:
@@ -75,6 +77,8 @@ jobs:
         working-directory: ./lib/sparesults
       - run: cargo clippy -- -D warnings -D clippy::all
         working-directory: ./lib/spargebra
+      - run: cargo clippy -- -D warnings -D clippy::all
+        working-directory: ./lib/sparopt
       - run: cargo clippy --all-targets -- -D warnings -D clippy::all
         working-directory: ./server
 

Cargo.lock

@@ -954,6 +954,7 @@ dependencies = [
  "siphasher",
  "sparesults",
  "spargebra",
+ "sparopt",
  "zstd",
 ]
 
@@ -1638,7 +1639,7 @@ dependencies = [
 
 [[package]]
 name = "spargebra"
-version = "0.2.7"
+version = "0.2.8-dev"
 dependencies = [
  "oxilangtag",
  "oxiri",
@@ -1647,6 +1648,15 @@ dependencies = [
  "rand",
 ]
 
+[[package]]
+name = "sparopt"
+version = "0.1.0-alpha.1"
+dependencies = [
+ "oxrdf",
+ "rand",
+ "spargebra",
+]
+
 [[package]]
 name = "sparql-smith"
 version = "0.1.0-alpha.3"

Cargo.toml

@@ -6,6 +6,7 @@ members = [
     "lib/oxsdatatypes",
     "lib/spargebra",
     "lib/sparesults",
+    "lib/sparopt",
     "lib/sparql-smith",
     "oxrocksdb-sys",
     "python",

fuzz/fuzz_targets/sparql_eval.rs

@@ -3,7 +3,7 @@
 use lazy_static::lazy_static;
 use libfuzzer_sys::fuzz_target;
 use oxigraph::io::DatasetFormat;
-use oxigraph::sparql::{Query, QueryOptions, QueryResults, QuerySolutionIter};
+use oxigraph::sparql::{Query, QueryOptions, QueryResults, QuerySolutionIter, RuleSet};
 use oxigraph::store::Store;
 
 lazy_static! {
@@ -26,24 +26,39 @@ fuzz_target!(|data: sparql_smith::Query| {
         let options = QueryOptions::default();
         let with_opt = STORE.query_opt(query.clone(), options.clone()).unwrap();
         let without_opt = STORE
-            .query_opt(query, options.without_optimizations())
+            .query_opt(query.clone(), options.clone().without_optimizations())
             .unwrap();
-        match (with_opt, without_opt) {
-            (QueryResults::Solutions(with_opt), QueryResults::Solutions(without_opt)) => {
-                assert_eq!(
-                    query_solutions_key(with_opt, query_str.contains(" REDUCED ")),
-                    query_solutions_key(without_opt, query_str.contains(" REDUCED "))
-                )
-            }
-            (QueryResults::Graph(_), QueryResults::Graph(_)) => unimplemented!(),
-            (QueryResults::Boolean(with_opt), QueryResults::Boolean(without_opt)) => {
-                assert_eq!(with_opt, without_opt)
-            }
-            _ => panic!("Different query result types"),
-        }
+        compare_results(with_opt, without_opt, &query_str);
+        let with_opt_and_reasoning = STORE
+            .query_opt(
+                query.clone(),
+                options
+                    .clone()
+                    .with_inference_rules(RuleSet::default())
+                    .clone(),
+            )
+            .unwrap();
+        let with_opt = STORE.query_opt(query.clone(), options).unwrap();
+        compare_results(with_opt, with_opt_and_reasoning, &query_str);
     }
 });
 
+fn compare_results(a: QueryResults, b: QueryResults, query_str: &str) {
+    match (a, b) {
+        (QueryResults::Solutions(a), QueryResults::Solutions(b)) => {
+            assert_eq!(
+                query_solutions_key(a, query_str.contains(" REDUCED ")),
+                query_solutions_key(b, query_str.contains(" REDUCED "))
+            )
+        }
+        (QueryResults::Graph(_), QueryResults::Graph(_)) => unimplemented!(),
+        (QueryResults::Boolean(a), QueryResults::Boolean(b)) => {
+            assert_eq!(a, b)
+        }
+        _ => panic!("Different query result types"),
+    }
+}
+
 fn query_solutions_key(iter: QuerySolutionIter, is_reduced: bool) -> String {
     // TODO: ordering
     let mut b = iter

lib/Cargo.toml

@@ -40,7 +40,8 @@ lazy_static = "1"
 json-event-parser = "0.1"
 oxrdf = { version = "0.1.5", path="oxrdf", features = ["rdf-star", "oxsdatatypes"] }
 oxsdatatypes = { version = "0.1.1", path="oxsdatatypes" }
-spargebra = { version = "0.2.7", path="spargebra", features = ["rdf-star", "sep-0002", "sep-0006"] }
+spargebra = { version = "0.2.8-dev", path="spargebra", features = ["rdf-star", "sep-0002", "sep-0006"] }
+sparopt = { version = "0.1.0-alpha.1", path="sparopt", features = ["rdf-star", "sep-0002", "sep-0006", "rules"] }
 sparesults = { version = "0.1.7", path="sparesults", features = ["rdf-star"] }
 
 [target.'cfg(not(target_family = "wasm"))'.dependencies]

lib/spargebra/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "spargebra"
-version = "0.2.7"
+version = "0.2.8-dev"
 authors = ["Tpt <thomas@pellissier-tanon.fr>"]
 license = "MIT OR Apache-2.0"
 readme = "README.md"
@@ -18,6 +18,7 @@ default = []
 rdf-star = ["oxrdf/rdf-star"]
 sep-0002 = []
 sep-0006 = []
+rules = []
 
 [dependencies]
 peg = "0.8"

lib/spargebra/src/lib.rs

@@ -8,9 +8,12 @@
 pub mod algebra;
 mod parser;
 mod query;
+mod rule;
 pub mod term;
 mod update;
 
 pub use parser::ParseError;
 pub use query::*;
+#[cfg(feature = "rules")]
+pub use rule::*;
 pub use update::*;

lib/spargebra/src/parser.rs

@@ -1,5 +1,6 @@
 use crate::algebra::*;
 use crate::query::*;
+use crate::rule::*;
 use crate::term::*;
 use crate::update::*;
 use oxilangtag::LanguageTag;
@@ -54,7 +55,7 @@ pub fn parse_update(update: &str, base_iri: Option<&str>) -> Result<Update, Pars
     };
 
     let operations =
-        parser::UpdateInit(&unescape_unicode_codepoints(update), &mut state).map_err(|e| {
+        parser::UpdateUnit(&unescape_unicode_codepoints(update), &mut state).map_err(|e| {
             ParseError {
                 inner: ParseErrorKind::Parser(e),
             }
@@ -65,6 +66,27 @@ pub fn parse_update(update: &str, base_iri: Option<&str>) -> Result<Update, Pars
     })
 }
 
+/// Parses a set of if/then rules with an optional base IRI to resolve relative IRIs in the rule.
+pub fn parse_rule_set(rules: &str, base_iri: Option<&str>) -> Result<RuleSet, ParseError> {
+    let mut state = ParserState {
+        base_iri: if let Some(base_iri) = base_iri {
+            Some(Iri::parse(base_iri.to_owned()).map_err(|e| ParseError {
+                inner: ParseErrorKind::InvalidBaseIri(e),
+            })?)
+        } else {
+            None
+        },
+        namespaces: HashMap::default(),
+        used_bnodes: HashSet::default(),
+        currently_used_bnodes: HashSet::default(),
+        aggregates: Vec::new(),
+    };
+
+    parser::RuleSetUnit(&unescape_unicode_codepoints(rules), &mut state).map_err(|e| ParseError {
+        inner: ParseErrorKind::Parser(e),
+    })
+}
+
 /// Error returned during SPARQL parsing.
 #[derive(Debug)]
 pub struct ParseError {
@@ -966,7 +988,7 @@ parser! {
         }
 
         //[3]
-        pub rule UpdateInit() -> Vec<GraphUpdateOperation> = Update()
+        pub rule UpdateUnit() -> Vec<GraphUpdateOperation> = Update()
 
         //[4]
         rule Prologue() = (BaseDecl() _ / PrefixDecl() _)* {}
@@ -2445,5 +2467,16 @@ parser! {
                 Err(literal)
             }
         }
+
+        pub rule RuleSetUnit() -> RuleSet = RuleSet()
+
+        rule RuleSet() -> RuleSet = _ Prologue() _ rules:(Rule() ** (_ ";" _))  _ ( ";" _)? { RuleSet { rules } }
+
+        rule Rule() -> Rule = i("IF") _ body:ConstructTemplate() _ i("THEN") _ head:ConstructTemplate() {?
+            Ok(Rule {
+                body,
+                head: head.into_iter().map(GroundTriplePattern::try_from).collect::<Result<_, ()>>().map_err(|_| "Blank nodes are not allowed in rules head")?
+            })
+        }
     }
 }

lib/spargebra/src/rule.rs

@@ -0,0 +1,120 @@
+#![cfg_attr(not(feature = "rules"), allow(dead_code))]
+use crate::parser::{parse_rule_set, ParseError};
+use crate::term::*;
+use std::fmt;
+use std::str::FromStr;
+
+/// A parsed if/then rule set.
+#[derive(Eq, PartialEq, Debug, Clone, Hash, Default)]
+pub struct RuleSet {
+    pub rules: Vec<Rule>,
+}
+
+impl RuleSet {
+    /// Parses a set of rules with an optional base IRI to resolve relative IRIs in the rules.
+    /// Note that this base IRI will not be used during execution.
+    pub fn parse(rules: &str, base_iri: Option<&str>) -> Result<Self, ParseError> {
+        parse_rule_set(rules, base_iri)
+    }
+
+    /// Formats using the [SPARQL S-Expression syntax](https://jena.apache.org/documentation/notes/sse.html).
+    pub fn to_sse(&self) -> String {
+        let mut buffer = String::new();
+        self.fmt_sse(&mut buffer).unwrap();
+        buffer
+    }
+
+    /// Formats using the [SPARQL S-Expression syntax](https://jena.apache.org/documentation/notes/sse.html).
+    fn fmt_sse(&self, f: &mut impl fmt::Write) -> fmt::Result {
+        write!(f, "(")?;
+        for (i, r) in self.rules.iter().enumerate() {
+            if i > 0 {
+                write!(f, " ")?;
+            }
+            r.fmt_sse(f)?;
+        }
+        write!(f, ") ")
+    }
+}
+
+impl fmt::Display for RuleSet {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for r in &self.rules {
+            writeln!(f, "{r} ;")?;
+        }
+        Ok(())
+    }
+}
+
+impl FromStr for RuleSet {
+    type Err = ParseError;
+
+    fn from_str(rules: &str) -> Result<Self, ParseError> {
+        Self::parse(rules, None)
+    }
+}
+
+impl<'a> TryFrom<&'a str> for RuleSet {
+    type Error = ParseError;
+
+    fn try_from(rules: &str) -> Result<Self, ParseError> {
+        Self::from_str(rules)
+    }
+}
+
+impl<'a> TryFrom<&'a String> for RuleSet {
+    type Error = ParseError;
+
+    fn try_from(rules: &String) -> Result<Self, ParseError> {
+        Self::from_str(rules)
+    }
+}
+
+/// A parsed if/then rule.
+#[derive(Eq, PartialEq, Debug, Clone, Hash)]
+pub struct Rule {
+    /// The construction template.
+    pub head: Vec<GroundTriplePattern>,
+    /// The rule body graph pattern.
+    pub body: Vec<TriplePattern>,
+}
+
+impl Rule {
+    /// Formats using the [SPARQL S-Expression syntax](https://jena.apache.org/documentation/notes/sse.html).
+    pub fn to_sse(&self) -> String {
+        let mut buffer = String::new();
+        self.fmt_sse(&mut buffer).unwrap();
+        buffer
+    }
+
+    /// Formats using the [SPARQL S-Expression syntax](https://jena.apache.org/documentation/notes/sse.html).
+    fn fmt_sse(&self, f: &mut impl fmt::Write) -> fmt::Result {
+        write!(f, "(rule (")?;
+        for (i, t) in self.head.iter().enumerate() {
+            if i > 0 {
+                write!(f, " ")?;
+            }
+            t.fmt_sse(f)?;
+        }
+        write!(f, ") (bgp")?;
+        for pattern in &self.body {
+            write!(f, " ")?;
+            pattern.fmt_sse(f)?;
+        }
+        write!(f, "))")
+    }
+}
+
+impl fmt::Display for Rule {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "IF {{ ")?;
+        for triple in &self.body {
+            write!(f, "{triple} . ")?;
+        }
+        write!(f, "}} THEN {{ ")?;
+        for triple in &self.head {
+            write!(f, "{triple} . ")?;
+        }
+        write!(f, "}}")
+    }
+}

lib/spargebra/src/term.rs

@@ -541,6 +541,19 @@ impl From<NamedNodePattern> for TermPattern {
     }
 }
 
+impl From<GroundTermPattern> for TermPattern {
+    #[inline]
+    fn from(element: GroundTermPattern) -> Self {
+        match element {
+            GroundTermPattern::NamedNode(node) => node.into(),
+            GroundTermPattern::Literal(literal) => literal.into(),
+            #[cfg(feature = "rdf-star")]
+            GroundTermPattern::Triple(t) => TriplePattern::from(*t).into(),
+            GroundTermPattern::Variable(variable) => variable.into(),
+        }
+    }
+}
+
 impl TryFrom<TermPattern> for Subject {
     type Error = ();
 
@@ -577,6 +590,7 @@ pub enum GroundTermPattern {
     NamedNode(NamedNode),
     Literal(Literal),
     Variable(Variable),
+    #[cfg(feature = "rdf-star")]
     Triple(Box<GroundTriplePattern>),
 }
 
@@ -587,6 +601,7 @@ impl GroundTermPattern {
             Self::NamedNode(term) => write!(f, "{term}"),
             Self::Literal(term) => write!(f, "{term}"),
             Self::Variable(var) => write!(f, "{var}"),
+            #[cfg(feature = "rdf-star")]
             Self::Triple(triple) => triple.fmt_sse(f),
         }
     }
@@ -599,6 +614,7 @@ impl fmt::Display for GroundTermPattern {
             Self::NamedNode(term) => term.fmt(f),
             Self::Literal(term) => term.fmt(f),
             Self::Variable(var) => var.fmt(f),
+            #[cfg(feature = "rdf-star")]
             Self::Triple(triple) => write!(f, "<<{triple}>>"),
         }
     }
@@ -618,6 +634,7 @@ impl From<Literal> for GroundTermPattern {
     }
 }
 
+#[cfg(feature = "rdf-star")]
 impl From<GroundTriplePattern> for GroundTermPattern {
     #[inline]
     fn from(triple: GroundTriplePattern) -> Self {
@@ -795,6 +812,17 @@ impl From<Triple> for TriplePattern {
     }
 }
 
+impl From<GroundTriplePattern> for TriplePattern {
+    #[inline]
+    fn from(triple: GroundTriplePattern) -> Self {
+        Self {
+            subject: triple.subject.into(),
+            predicate: triple.predicate,
+            object: triple.object.into(),
+        }
+    }
+}
+
 impl TryFrom<TriplePattern> for Triple {
     type Error = ();
 
@@ -818,6 +846,7 @@ pub struct GroundTriplePattern {
 
 impl GroundTriplePattern {
     /// Formats using the [SPARQL S-Expression syntax](https://jena.apache.org/documentation/notes/sse.html).
+    #[allow(dead_code)]
     pub(crate) fn fmt_sse(&self, f: &mut impl Write) -> fmt::Result {
         write!(f, "(triple ")?;
         self.subject.fmt_sse(f)?;

lib/sparopt/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "sparopt"
+version = "0.1.0-alpha.1"
+authors = ["Tpt <thomas@pellissier-tanon.fr>"]
+license = "MIT OR Apache-2.0"
+readme = "README.md"
+keywords = ["SPARQL"]
+repository = "https://github.com/oxigraph/oxigraph/tree/main/lib/sparopt"
+homepage = "https://oxigraph.org/"
+description = """
+A SPARQL optimizer
+"""
+edition = "2021"
+rust-version = "1.60"
+
+[features]
+default = []
+fixed-point = []
+rdf-star = ["oxrdf/rdf-star", "spargebra/rdf-star"]
+sep-0002 = ["spargebra/sep-0002"]
+sep-0006 = ["spargebra/sep-0006"]
+rules = ["spargebra/rules", "fixed-point"]
+
+[dependencies]
+oxrdf = { version = "0.1.5", path="../oxrdf" }
+rand = "0.8"
+spargebra = { version = "0.2.8-dev", path="../spargebra" }
+
+[package.metadata.docs.rs]
+all-features = true

lib/sparopt/README.md

@@ -0,0 +1,32 @@
+sparopt
+=========
+
+[![Latest Version](https://img.shields.io/crates/v/sparopt.svg)](https://crates.io/crates/sparopt)
+[![Released API docs](https://docs.rs/sparopt/badge.svg)](https://docs.rs/sparopt)
+[![Crates.io downloads](https://img.shields.io/crates/d/sparopt)](https://crates.io/crates/sparopt)
+[![actions status](https://github.com/oxigraph/oxigraph/workflows/build/badge.svg)](https://github.com/oxigraph/oxigraph/actions)
+[![Gitter](https://badges.gitter.im/oxigraph/community.svg)](https://gitter.im/oxigraph/community?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
+
+sparopt is a work in progress [SPARQL Query](https://www.w3.org/TR/sparql11-query/) optimizer.
+
+It relies on the output of [spargebra](https://crates.io/crates/spargebra).
+
+Support for [SPARQL-star](https://w3c.github.io/rdf-star/cg-spec/#sparql-star) is also available behind the `rdf-star` feature.
+
+This crate is intended to be a building piece for SPARQL implementations in Rust like [Oxigraph](https://oxigraph.org).
+
+## License
+
+This project is licensed under either of
+
+* Apache License, Version 2.0, ([LICENSE-APACHE](../LICENSE-APACHE) or
+  `<http://www.apache.org/licenses/LICENSE-2.0>`)
+* MIT license ([LICENSE-MIT](../LICENSE-MIT) or
+  `<http://opensource.org/licenses/MIT>`)
+
+at your option.
+
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Oxigraph by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

lib/sparopt/src/lib.rs

@@ -0,0 +1,8 @@
+pub use crate::optimizer::Optimizer;
+#[cfg(feature = "rules")]
+pub use crate::reasoning::QueryRewriter;
+
+pub mod algebra;
+mod optimizer;
+#[cfg(feature = "rules")]
+mod reasoning;

lib/sparopt/src/optimizer.rs

@@ -0,0 +1,195 @@
+use crate::algebra::{Expression, FixedPointGraphPattern, GraphPattern};
+
+#[derive(Default)]
+pub struct Optimizer {}
+
+impl Optimizer {
+    pub fn optimize(&mut self, pattern: GraphPattern) -> GraphPattern {
+        Self::normalize_pattern(pattern)
+    }
+
+    fn normalize_pattern(pattern: GraphPattern) -> GraphPattern {
+        match pattern {
+            GraphPattern::QuadPattern {
+                subject,
+                predicate,
+                object,
+                graph_name,
+            } => GraphPattern::QuadPattern {
+                subject,
+                predicate,
+                object,
+                graph_name,
+            },
+            GraphPattern::Path {
+                subject,
+                path,
+                object,
+                graph_name,
+            } => GraphPattern::Path {
+                subject,
+                path,
+                object,
+                graph_name,
+            },
+            GraphPattern::Join { left, right } => GraphPattern::join(
+                Self::normalize_pattern(*left),
+                Self::normalize_pattern(*right),
+            ),
+            GraphPattern::LeftJoin {
+                left,
+                right,
+                expression,
+            } => GraphPattern::left_join(
+                Self::normalize_pattern(*left),
+                Self::normalize_pattern(*right),
+                Self::normalize_expression(expression),
+            ),
+            #[cfg(feature = "sep-0006")]
+            GraphPattern::Lateral { left, right } => GraphPattern::lateral(
+                Self::normalize_pattern(*left),
+                Self::normalize_pattern(*right),
+            ),
+            GraphPattern::Filter { inner, expression } => GraphPattern::filter(
+                Self::normalize_pattern(*inner),
+                Self::normalize_expression(expression),
+            ),
+            GraphPattern::Union { inner } => inner
+                .into_iter()
+                .map(Self::normalize_pattern)
+                .reduce(GraphPattern::union)
+                .unwrap_or_else(GraphPattern::empty),
+            GraphPattern::Extend {
+                inner,
+                variable,
+                expression,
+            } => GraphPattern::extend(Self::normalize_pattern(*inner), variable, expression),
+            GraphPattern::Minus { left, right } => GraphPattern::minus(
+                Self::normalize_pattern(*left),
+                Self::normalize_pattern(*right),
+            ),
+            GraphPattern::Values {
+                variables,
+                bindings,
+            } => GraphPattern::values(variables, bindings),
+            GraphPattern::OrderBy { inner, expression } => {
+                GraphPattern::order_by(Self::normalize_pattern(*inner), expression)
+            }
+            GraphPattern::Project { inner, variables } => {
+                GraphPattern::project(Self::normalize_pattern(*inner), variables)
+            }
+            GraphPattern::Distinct { inner } => {
+                GraphPattern::distinct(Self::normalize_pattern(*inner))
+            }
+            GraphPattern::Reduced { inner } => {
+                GraphPattern::reduced(Self::normalize_pattern(*inner))
+            }
+            GraphPattern::Slice {
+                inner,
+                start,
+                length,
+            } => GraphPattern::slice(Self::normalize_pattern(*inner), start, length),
+            GraphPattern::Group {
+                inner,
+                variables,
+                aggregates,
+            } => GraphPattern::group(Self::normalize_pattern(*inner), variables, aggregates),
+            GraphPattern::Service {
+                name,
+                inner,
+                silent,
+            } => GraphPattern::service(Self::normalize_pattern(*inner), name, silent),
+            #[cfg(feature = "fixed-point")]
+            GraphPattern::FixedPoint {
+                id,
+                variables,
+                constant,
+                recursive,
+            } => {
+                GraphPattern::fixed_point(
+                    id,
+                    FixedPointGraphPattern::union(*constant, *recursive),
+                    variables,
+                )
+                //TODO: recursive normalization
+            }
+        }
+    }
+
+    fn normalize_expression(expression: Expression) -> Expression {
+        match expression {
+            Expression::NamedNode(node) => node.into(),
+            Expression::Literal(literal) => literal.into(),
+            Expression::Variable(variable) => variable.into(),
+            Expression::Or(left, right) => Expression::or(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::And(left, right) => Expression::and(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::Equal(left, right) => Expression::equal(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::SameTerm(left, right) => Expression::same_term(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::Greater(left, right) => Expression::greater(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::GreaterOrEqual(left, right) => Expression::greater_or_equal(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::Less(left, right) => Expression::less(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::LessOrEqual(left, right) => Expression::less_or_equal(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::Add(left, right) => Expression::add(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::Subtract(left, right) => Expression::subtract(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::Multiply(left, right) => Expression::multiply(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::Divide(left, right) => Expression::divide(
+                Self::normalize_expression(*left),
+                Self::normalize_expression(*right),
+            ),
+            Expression::UnaryPlus(inner) => {
+                Expression::unary_plus(Self::normalize_expression(*inner))
+            }
+            Expression::UnaryMinus(inner) => {
+                Expression::unary_minus(Self::normalize_expression(*inner))
+            }
+            Expression::Not(inner) => Expression::not(Self::normalize_expression(*inner)),
+            Expression::Exists(inner) => Expression::exists(Self::normalize_pattern(*inner)),
+            Expression::Bound(variable) => Expression::Bound(variable),
+            Expression::If(cond, then, els) => Expression::if_cond(
+                Self::normalize_expression(*cond),
+                Self::normalize_expression(*then),
+                Self::normalize_expression(*els),
+            ),
+            Expression::Coalesce(inners) => {
+                Expression::coalesce(inners.into_iter().map(Self::normalize_expression).collect())
+            }
+            Expression::FunctionCall(name, args) => Expression::call(
+                name,
+                args.into_iter().map(Self::normalize_expression).collect(),
+            ),
+        }
+    }
+}

lib/src/sparql/algebra.rs

@@ -181,6 +181,56 @@ impl<'a> TryFrom<&'a String> for Update {
     }
 }
 
+/// A parsed rule set.
+#[derive(Eq, PartialEq, Debug, Clone, Hash, Default)]
+pub struct RuleSet {
+    pub(super) inner: spargebra::RuleSet,
+}
+
+impl RuleSet {
+    /// Parses a rule set with an optional base IRI to resolve relative IRIs in the rule set.
+    pub fn parse(rule_set: &str, base_iri: Option<&str>) -> Result<Self, spargebra::ParseError> {
+        let rule_set = spargebra::RuleSet::parse(rule_set, base_iri)?;
+        Ok(rule_set.into())
+    }
+}
+
+impl fmt::Display for RuleSet {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.inner.fmt(f) //TODO: override
+    }
+}
+
+impl FromStr for RuleSet {
+    type Err = spargebra::ParseError;
+
+    fn from_str(rule_set: &str) -> Result<Self, spargebra::ParseError> {
+        Self::parse(rule_set, None)
+    }
+}
+
+impl<'a> TryFrom<&'a str> for RuleSet {
+    type Error = spargebra::ParseError;
+
+    fn try_from(rule_set: &str) -> Result<Self, spargebra::ParseError> {
+        Self::from_str(rule_set)
+    }
+}
+
+impl<'a> TryFrom<&'a String> for RuleSet {
+    type Error = spargebra::ParseError;
+
+    fn try_from(rule_set: &String) -> Result<Self, spargebra::ParseError> {
+        Self::from_str(rule_set)
+    }
+}
+
+impl From<spargebra::RuleSet> for RuleSet {
+    fn from(rule_set: spargebra::RuleSet) -> Self {
+        Self { inner: rule_set }
+    }
+}
+
 /// A SPARQL query [dataset specification](https://www.w3.org/TR/sparql11-query/#specifyingDataset)
 #[derive(Eq, PartialEq, Debug, Clone, Hash)]
 pub struct QueryDataset {

lib/src/sparql/eval.rs

@@ -36,6 +36,8 @@ const REGEX_SIZE_LIMIT: usize = 1_000_000;
 
 type EncodedTuplesIterator = Box<dyn Iterator<Item = Result<EncodedTuple, EvaluationError>>>;
 type CustomFunctionRegistry = HashMap<NamedNode, Rc<dyn Fn(&[Term]) -> Option<Term>>>;
+type FixedPointEvaluationFn =
+    Rc<dyn Fn(EncodedTuple, HashMap<usize, Rc<Vec<EncodedTuple>>>) -> EncodedTuplesIterator>;
 
 #[derive(Clone)]
 pub struct SimpleEvaluator {
@@ -144,6 +146,7 @@ impl SimpleEvaluator {
         Rc<PlanNodeWithStats>,
     ) {
         let mut stat_children = Vec::new();
+        let mut fixed_point_stat_children = Vec::new();
         let mut evaluator: Rc<dyn Fn(EncodedTuple) -> EncodedTuplesIterator> = match node.as_ref() {
             PlanNode::StaticBindings { encoded_tuples, .. } => {
                 let tuples = encoded_tuples.clone();
@@ -817,10 +820,26 @@ impl SimpleEvaluator {
                     )
                 })
             }
+            PlanNode::FixedPoint {
+                id,
+                constant,
+                recursive,
+            } => {
+                let (constant, constant_stats) = self.fixed_point_plan_evaluator(constant.clone());
+                fixed_point_stat_children.push(constant_stats);
+                let (recursive, recursive_stats) =
+                    self.fixed_point_plan_evaluator(recursive.clone());
+                fixed_point_stat_children.push(recursive_stats);
+                let id = *id;
+                Rc::new(move |from| {
+                    evaluate_fixed_point(id, &constant, &recursive, &from, &HashMap::new())
+                })
+            }
         };
         let stats = Rc::new(PlanNodeWithStats {
             node,
             children: stat_children,
+            fixed_point_children: fixed_point_stat_children,
             exec_count: Cell::new(0),
             exec_duration: Cell::new(std::time::Duration::from_secs(0)),
         });
@@ -841,6 +860,258 @@ impl SimpleEvaluator {
         (evaluator, stats)
     }
 
+    pub fn fixed_point_plan_evaluator(
+        &self,
+        node: Rc<FixedPointPlanNode>,
+    ) -> (FixedPointEvaluationFn, Rc<FixedPointPlanNodeWithStats>) {
+        let mut stat_children = Vec::new();
+        let mut evaluator: Rc<
+            dyn Fn(EncodedTuple, HashMap<usize, Rc<Vec<EncodedTuple>>>) -> EncodedTuplesIterator,
+        > = match node.as_ref() {
+            FixedPointPlanNode::StaticBindings { encoded_tuples, .. } => {
+                let tuples = encoded_tuples.clone();
+                Rc::new(move |from, _| {
+                    Box::new(
+                        tuples
+                            .iter()
+                            .filter_map(move |t| Some(Ok(t.combine_with(&from)?)))
+                            .collect::<Vec<_>>()
+                            .into_iter(),
+                    )
+                })
+            }
+            FixedPointPlanNode::QuadPattern {
+                subject,
+                predicate,
+                object,
+                graph_name,
+            } => {
+                let subject = TupleSelector::from(subject);
+                let predicate = TupleSelector::from(predicate);
+                let object = TupleSelector::from(object);
+                let graph_name = TupleSelector::from(graph_name);
+                let dataset = self.dataset.clone();
+                Rc::new(move |from, _| {
+                    let iter = dataset.encoded_quads_for_pattern(
+                        get_pattern_value(&subject, &from).as_ref(),
+                        get_pattern_value(&predicate, &from).as_ref(),
+                        get_pattern_value(&object, &from).as_ref(),
+                        get_pattern_value(&graph_name, &from).as_ref(),
+                    );
+                    let subject = subject.clone();
+                    let predicate = predicate.clone();
+                    let object = object.clone();
+                    let graph_name = graph_name.clone();
+                    Box::new(iter.filter_map(move |quad| match quad {
+                        Ok(quad) => {
+                            let mut new_tuple = from.clone();
+                            put_pattern_value(&subject, quad.subject, &mut new_tuple)?;
+                            put_pattern_value(&predicate, quad.predicate, &mut new_tuple)?;
+                            put_pattern_value(&object, quad.object, &mut new_tuple)?;
+                            put_pattern_value(&graph_name, quad.graph_name, &mut new_tuple)?;
+                            Some(Ok(new_tuple))
+                        }
+                        Err(error) => Some(Err(error)),
+                    }))
+                })
+            }
+            FixedPointPlanNode::HashJoin { left, right } => {
+                let join_keys: Vec<_> = left
+                    .used_variables()
+                    .intersection(&right.used_variables())
+                    .copied()
+                    .collect();
+                let (left, left_stats) = self.fixed_point_plan_evaluator(left.clone());
+                stat_children.push(left_stats);
+                let (right, right_stats) = self.fixed_point_plan_evaluator(right.clone());
+                stat_children.push(right_stats);
+                if join_keys.is_empty() {
+                    // Cartesian product
+                    Rc::new(move |from, fixed_point_values| {
+                        let mut errors = Vec::default();
+                        let right_values = right(from.clone(), fixed_point_values.clone())
+                            .filter_map(|result| match result {
+                                Ok(result) => Some(result),
+                                Err(error) => {
+                                    errors.push(Err(error));
+                                    None
+                                }
+                            })
+                            .collect::<Vec<_>>();
+                        Box::new(CartesianProductJoinIterator {
+                            left_iter: left(from, fixed_point_values),
+                            right: right_values,
+                            buffered_results: errors,
+                        })
+                    })
+                } else {
+                    // Real hash join
+                    Rc::new(move |from, fixed_point_values| {
+                        let mut errors = Vec::default();
+                        let mut right_values = EncodedTupleSet::new(join_keys.clone());
+                        right_values.extend(
+                            right(from.clone(), fixed_point_values.clone()).filter_map(|result| {
+                                match result {
+                                    Ok(result) => Some(result),
+                                    Err(error) => {
+                                        errors.push(Err(error));
+                                        None
+                                    }
+                                }
+                            }),
+                        );
+                        Box::new(HashJoinIterator {
+                            left_iter: left(from, fixed_point_values),
+                            right: right_values,
+                            buffered_results: errors,
+                        })
+                    })
+                }
+            }
+            FixedPointPlanNode::Filter { child, expression } => {
+                let (child, child_stats) = self.fixed_point_plan_evaluator(child.clone());
+                stat_children.push(child_stats);
+                let expression = self.expression_evaluator(expression);
+                Rc::new(move |from, fixed_point_values| {
+                    let expression = expression.clone();
+                    Box::new(child(from, fixed_point_values).filter(move |tuple| {
+                        match tuple {
+                            Ok(tuple) => expression(tuple)
+                                .and_then(|term| to_bool(&term))
+                                .unwrap_or(false),
+                            Err(_) => true,
+                        }
+                    }))
+                })
+            }
+            FixedPointPlanNode::Union { children } => {
+                let children: Vec<_> = children
+                    .iter()
+                    .map(|child| {
+                        let (child, child_stats) = self.fixed_point_plan_evaluator(child.clone());
+                        stat_children.push(child_stats);
+                        child
+                    })
+                    .collect();
+                Rc::new(move |from, fixed_point_values| {
+                    Box::new(FixedPointUnionIterator {
+                        plans: children.clone(),
+                        input: (from, fixed_point_values),
+                        current_iterator: Box::new(empty()),
+                        current_plan: 0,
+                    })
+                })
+            }
+            FixedPointPlanNode::Extend {
+                child,
+                variable,
+                expression,
+            } => {
+                let (child, child_stats) = self.fixed_point_plan_evaluator(child.clone());
+                stat_children.push(child_stats);
+                let position = variable.encoded;
+                let expression = self.expression_evaluator(expression);
+                Rc::new(move |from, fixed_point_values| {
+                    let expression = expression.clone();
+                    Box::new(child(from, fixed_point_values).map(move |tuple| {
+                        let mut tuple = tuple?;
+                        if let Some(value) = expression(&tuple) {
+                            tuple.set(position, value);
+                        }
+                        Ok(tuple)
+                    }))
+                })
+            }
+            FixedPointPlanNode::Project { child, mapping } => {
+                let (child, child_stats) = self.fixed_point_plan_evaluator(child.clone());
+                stat_children.push(child_stats);
+                let mapping = mapping.clone();
+                Rc::new(move |from, fixed_point_values| {
+                    let mapping = mapping.clone();
+                    let mut input_tuple = EncodedTuple::with_capacity(mapping.len());
+                    for (input_key, output_key) in mapping.iter() {
+                        if let Some(value) = from.get(output_key.encoded) {
+                            input_tuple.set(input_key.encoded, value.clone());
+                        }
+                    }
+                    Box::new(
+                        child(input_tuple, fixed_point_values).filter_map(move |tuple| {
+                            match tuple {
+                                Ok(tuple) => {
+                                    let mut output_tuple = from.clone();
+                                    for (input_key, output_key) in mapping.iter() {
+                                        if let Some(value) = tuple.get(input_key.encoded) {
+                                            if let Some(existing_value) =
+                                                output_tuple.get(output_key.encoded)
+                                            {
+                                                if existing_value != value {
+                                                    return None; // Conflict
+                                                }
+                                            } else {
+                                                output_tuple.set(output_key.encoded, value.clone());
+                                            }
+                                        }
+                                    }
+                                    Some(Ok(output_tuple))
+                                }
+                                Err(e) => Some(Err(e)),
+                            }
+                        }),
+                    )
+                })
+            }
+            FixedPointPlanNode::FixedPoint {
+                id,
+                constant,
+                recursive,
+            } => {
+                let (constant, constant_stats) = self.fixed_point_plan_evaluator(constant.clone());
+                stat_children.push(constant_stats);
+                let (recursive, recursive_stats) =
+                    self.fixed_point_plan_evaluator(recursive.clone());
+                stat_children.push(recursive_stats);
+                let id = *id;
+                Rc::new(move |from, fixed_point_values| {
+                    evaluate_fixed_point(id, &constant, &recursive, &from, &fixed_point_values)
+                })
+            }
+            FixedPointPlanNode::FixedPointEntry { id, .. } => {
+                let id = *id;
+                Rc::new(move |from, fixed_point_values| {
+                    Box::new(
+                        fixed_point_values[&id]
+                            .as_ref()
+                            .clone()
+                            .into_iter()
+                            .filter_map(move |t| t.combine_with(&from))
+                            .map(Ok),
+                    )
+                })
+            }
+        };
+        let stats = Rc::new(FixedPointPlanNodeWithStats {
+            node,
+            children: stat_children,
+            exec_count: Cell::new(0),
+            exec_duration: Cell::new(std::time::Duration::from_secs(0)),
+        });
+        if self.run_stats {
+            let stats = stats.clone();
+            evaluator = Rc::new(move |tuple, fixed_point_values| {
+                let start = Timer::now();
+                let inner = evaluator(tuple, fixed_point_values);
+                stats
+                    .exec_duration
+                    .set(stats.exec_duration.get() + start.elapsed());
+                Box::new(FixedPointStatsIterator {
+                    inner,
+                    stats: stats.clone(),
+                })
+            })
+        }
+        (evaluator, stats)
+    }
+
     fn evaluate_service(
         &self,
         service_name: &PatternValue,
@@ -3883,6 +4154,52 @@ impl PathEvaluator {
     }
 }
 
+fn evaluate_fixed_point(
+    id: usize,
+    constant: &FixedPointEvaluationFn,
+    recursive: &FixedPointEvaluationFn,
+    from: &EncodedTuple,
+    fixed_point_values: &HashMap<usize, Rc<Vec<EncodedTuple>>>,
+) -> EncodedTuplesIterator {
+    // Naive algorithm. We should at least be semi-naive
+    let mut errors = Vec::new();
+    let mut all_results = constant(from.clone(), HashMap::new())
+        .filter_map(|result| match result {
+            Ok(result) => Some(result),
+            Err(error) => {
+                errors.push(error);
+                None
+            }
+        })
+        .collect::<HashSet<_>>();
+    let mut new_set = all_results.iter().cloned().collect::<Vec<_>>();
+    while !new_set.is_empty() {
+        let mut fixed_point_values = fixed_point_values.clone();
+        fixed_point_values.insert(id, Rc::new(all_results.iter().cloned().collect()));
+        new_set = recursive(from.clone(), fixed_point_values)
+            .filter_map(|result| match result {
+                Ok(result) => {
+                    if all_results.insert(result.clone()) {
+                        Some(result)
+                    } else {
+                        None
+                    }
+                }
+                Err(error) => {
+                    errors.push(error);
+                    None
+                }
+            })
+            .collect();
+    }
+    Box::new(
+        errors
+            .into_iter()
+            .map(Err)
+            .chain(all_results.into_iter().map(Ok)),
+    )
+}
+
 struct CartesianProductJoinIterator {
     left_iter: EncodedTuplesIterator,
     right: Vec<EncodedTuple>,
@@ -4109,6 +4426,31 @@ impl Iterator for UnionIterator {
     }
 }
 
+struct FixedPointUnionIterator {
+    plans: Vec<FixedPointEvaluationFn>,
+    input: (EncodedTuple, HashMap<usize, Rc<Vec<EncodedTuple>>>),
+    current_iterator: EncodedTuplesIterator,
+    current_plan: usize,
+}
+
+impl Iterator for FixedPointUnionIterator {
+    type Item = Result<EncodedTuple, EvaluationError>;
+
+    fn next(&mut self) -> Option<Result<EncodedTuple, EvaluationError>> {
+        loop {
+            if let Some(tuple) = self.current_iterator.next() {
+                return Some(tuple);
+            }
+            if self.current_plan >= self.plans.len() {
+                return None;
+            }
+            self.current_iterator =
+                self.plans[self.current_plan](self.input.0.clone(), self.input.1.clone());
+            self.current_plan += 1;
+        }
+    }
+}
+
 struct ConsecutiveDeduplication {
     inner: EncodedTuplesIterator,
     current: Option<EncodedTuple>,
@@ -4802,6 +5144,27 @@ impl Iterator for StatsIterator {
     }
 }
 
+struct FixedPointStatsIterator {
+    inner: EncodedTuplesIterator,
+    stats: Rc<FixedPointPlanNodeWithStats>,
+}
+
+impl Iterator for FixedPointStatsIterator {
+    type Item = Result<EncodedTuple, EvaluationError>;
+
+    fn next(&mut self) -> Option<Result<EncodedTuple, EvaluationError>> {
+        let start = Timer::now();
+        let result = self.inner.next();
+        self.stats
+            .exec_duration
+            .set(self.stats.exec_duration.get() + start.elapsed());
+        if matches!(result, Some(Ok(_))) {
+            self.stats.exec_count.set(self.stats.exec_count.get() + 1);
+        }
+        result
+    }
+}
+
 #[cfg(all(target_family = "wasm", target_os = "unknown"))]
 pub struct Timer {
     timestamp_ms: f64,

lib/src/sparql/mod.rs

@@ -14,7 +14,7 @@ mod service;
 mod update;
 
 use crate::model::{NamedNode, Term};
-pub use crate::sparql::algebra::{Query, QueryDataset, Update};
+pub use crate::sparql::algebra::{Query, QueryDataset, RuleSet, Update};
 use crate::sparql::dataset::DatasetView;
 pub use crate::sparql::error::{EvaluationError, QueryError};
 use crate::sparql::eval::{SimpleEvaluator, Timer};
@@ -29,6 +29,7 @@ use json_event_parser::{JsonEvent, JsonWriter};
 pub use oxrdf::{Variable, VariableNameParseError};
 pub use sparesults::QueryResultsFormat;
 pub use spargebra::ParseError;
+use sparopt::QueryRewriter;
 use std::collections::HashMap;
 use std::rc::Rc;
 use std::time::Duration;
@@ -53,6 +54,7 @@ pub(crate) fn evaluate_query(
                 &pattern,
                 true,
                 &options.custom_functions,
+                options.query_rewriter.as_ref(),
                 options.without_optimizations,
             )?;
             let planning_duration = start_planning.elapsed();
@@ -74,6 +76,7 @@ pub(crate) fn evaluate_query(
                 &pattern,
                 false,
                 &options.custom_functions,
+                options.query_rewriter.as_ref(),
                 options.without_optimizations,
             )?;
             let planning_duration = start_planning.elapsed();
@@ -98,6 +101,7 @@ pub(crate) fn evaluate_query(
                 &pattern,
                 false,
                 &options.custom_functions,
+                options.query_rewriter.as_ref(),
                 options.without_optimizations,
             )?;
             let construct = PlanBuilder::build_graph_template(
@@ -126,6 +130,7 @@ pub(crate) fn evaluate_query(
                 &pattern,
                 false,
                 &options.custom_functions,
+                options.query_rewriter.as_ref(),
                 options.without_optimizations,
             )?;
             let planning_duration = start_planning.elapsed();
@@ -174,6 +179,7 @@ pub struct QueryOptions {
     http_timeout: Option<Duration>,
     http_redirection_limit: usize,
     without_optimizations: bool,
+    query_rewriter: Option<Rc<QueryRewriter>>,
 }
 
 impl QueryOptions {
@@ -267,6 +273,13 @@ impl QueryOptions {
         self.without_optimizations = true;
         self
     }
+
+    #[inline]
+    #[must_use]
+    pub fn with_inference_rules(mut self, rules: RuleSet) -> Self {
+        self.query_rewriter = Some(Rc::new(QueryRewriter::new(rules.inner)));
+        self
+    }
 }
 
 /// Options for SPARQL update evaluation.

lib/src/sparql/plan.rs

@@ -107,6 +107,11 @@ pub enum PlanNode {
         key_variables: Rc<Vec<PlanVariable>>,
         aggregates: Rc<Vec<(PlanAggregation, PlanVariable)>>,
     },
+    FixedPoint {
+        id: usize,
+        constant: Rc<FixedPointPlanNode>,
+        recursive: Rc<FixedPointPlanNode>,
+    },
 }
 
 impl PlanNode {
@@ -218,6 +223,14 @@ impl PlanNode {
                     callback(var.encoded);
                 }
             }
+            Self::FixedPoint {
+                constant,
+                recursive,
+                ..
+            } => {
+                constant.lookup_used_variables(callback);
+                recursive.lookup_used_variables(callback);
+            }
         }
     }
 
@@ -336,7 +349,7 @@ impl PlanNode {
                     }
                 }
             }
-            Self::Aggregate { .. } => {
+            Self::Aggregate { .. } | Self::FixedPoint { .. } => {
                 //TODO
             }
         }
@@ -353,6 +366,130 @@ impl PlanNode {
     }
 }
 
+#[derive(Debug)]
+pub enum FixedPointPlanNode {
+    StaticBindings {
+        encoded_tuples: Vec<EncodedTuple>,
+        variables: Vec<PlanVariable>,
+        plain_bindings: Vec<Vec<Option<GroundTerm>>>,
+    },
+    QuadPattern {
+        subject: PatternValue,
+        predicate: PatternValue,
+        object: PatternValue,
+        graph_name: PatternValue,
+    },
+    /// Streams left and materializes right join
+    HashJoin {
+        left: Rc<Self>,
+        right: Rc<Self>,
+    },
+    Filter {
+        child: Rc<Self>,
+        expression: PlanExpression,
+    },
+    Union {
+        children: Vec<Rc<Self>>,
+    },
+    Extend {
+        child: Rc<Self>,
+        variable: PlanVariable,
+        expression: PlanExpression,
+    },
+    Project {
+        child: Rc<Self>,
+        mapping: Rc<Vec<(PlanVariable, PlanVariable)>>, // pairs of (variable key in child, variable key in output)
+    },
+    FixedPoint {
+        id: usize,
+        constant: Rc<Self>,
+        recursive: Rc<Self>,
+    },
+    FixedPointEntry {
+        id: usize,
+        variables: Vec<PlanVariable>,
+    },
+}
+
+impl FixedPointPlanNode {
+    /// Returns variables that might be bound in the result set
+    pub fn used_variables(&self) -> BTreeSet<usize> {
+        let mut set = BTreeSet::default();
+        self.lookup_used_variables(&mut |v| {
+            set.insert(v);
+        });
+        set
+    }
+
+    pub fn lookup_used_variables(&self, callback: &mut impl FnMut(usize)) {
+        match self {
+            Self::StaticBindings { encoded_tuples, .. } => {
+                for tuple in encoded_tuples {
+                    for (key, value) in tuple.iter().enumerate() {
+                        if value.is_some() {
+                            callback(key);
+                        }
+                    }
+                }
+            }
+            Self::QuadPattern {
+                subject,
+                predicate,
+                object,
+                graph_name,
+            } => {
+                subject.lookup_variables(callback);
+                predicate.lookup_variables(callback);
+                object.lookup_variables(callback);
+                graph_name.lookup_variables(callback);
+            }
+            Self::Filter { child, expression } => {
+                expression.lookup_used_variables(callback);
+                child.lookup_used_variables(callback);
+            }
+            Self::Union { children } => {
+                for child in children.iter() {
+                    child.lookup_used_variables(callback);
+                }
+            }
+            Self::HashJoin { left, right } => {
+                left.lookup_used_variables(callback);
+                right.lookup_used_variables(callback);
+            }
+            Self::Extend {
+                child,
+                variable,
+                expression,
+            } => {
+                callback(variable.encoded);
+                expression.lookup_used_variables(callback);
+                child.lookup_used_variables(callback);
+            }
+            Self::Project { mapping, child } => {
+                let child_bound = child.used_variables();
+                for (child_i, output_i) in mapping.iter() {
+                    if child_bound.contains(&child_i.encoded) {
+                        callback(output_i.encoded);
+                    }
+                }
+            }
+            Self::FixedPoint {
+                constant,
+                recursive,
+                ..
+            } => {
+                constant.lookup_used_variables(callback);
+                recursive.lookup_used_variables(callback);
+            }
+            Self::FixedPointEntry { variables, .. } => {
+                for variable in variables {
+                    callback(variable.encoded);
+                }
+            }
+        }
+    }
+}
+
 #[derive(Debug, Clone)]
 pub struct PlanTerm<T> {
     pub encoded: EncodedTerm,
@@ -1005,7 +1142,8 @@ impl IntoIterator for EncodedTuple {
 
 pub struct PlanNodeWithStats {
     pub node: Rc<PlanNode>,
-    pub children: Vec<Rc<PlanNodeWithStats>>,
+    pub children: Vec<Rc<Self>>,
+    pub fixed_point_children: Vec<Rc<FixedPointPlanNodeWithStats>>,
     pub exec_count: Cell<usize>,
     pub exec_duration: Cell<Duration>,
 }
@@ -1032,6 +1170,9 @@ impl PlanNodeWithStats {
         for child in &self.children {
             child.json_node(writer, with_stats)?;
         }
+        for child in &self.fixed_point_children {
+            child.json_node(writer, with_stats)?;
+        }
         writer.write_event(JsonEvent::EndArray)?;
         writer.write_event(JsonEvent::EndObject)
     }
@@ -1123,11 +1264,110 @@ impl PlanNodeWithStats {
                 )
             }
             PlanNode::Union { .. } => "Union".to_owned(),
+            PlanNode::FixedPoint { id, .. } => format!("FixedPoint{id}"),
         }
     }
 }
 
 impl fmt::Debug for PlanNodeWithStats {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut obj = f.debug_struct("Node");
+        obj.field("name", &self.node_label());
+        if self.exec_duration.get() > Duration::default() {
+            obj.field("number of results", &self.exec_count.get());
+            obj.field("duration in seconds", &self.exec_duration.get());
+        }
+        if !self.children.is_empty() {
+            obj.field("children", &self.children);
+        }
+        if !self.fixed_point_children.is_empty() {
+            obj.field("children", &self.fixed_point_children);
+        }
+        obj.finish()
+    }
+}
+
+pub struct FixedPointPlanNodeWithStats {
+    pub node: Rc<FixedPointPlanNode>,
+    pub children: Vec<Rc<Self>>,
+    pub exec_count: Cell<usize>,
+    pub exec_duration: Cell<Duration>,
+}
+
+impl FixedPointPlanNodeWithStats {
+    pub fn json_node(
+        &self,
+        writer: &mut JsonWriter<impl io::Write>,
+        with_stats: bool,
+    ) -> io::Result<()> {
+        writer.write_event(JsonEvent::StartObject)?;
+        writer.write_event(JsonEvent::ObjectKey("name"))?;
+        writer.write_event(JsonEvent::String(&self.node_label()))?;
+        if with_stats {
+            writer.write_event(JsonEvent::ObjectKey("number of results"))?;
+            writer.write_event(JsonEvent::Number(&self.exec_count.get().to_string()))?;
+            writer.write_event(JsonEvent::ObjectKey("duration in seconds"))?;
+            writer.write_event(JsonEvent::Number(
+                &self.exec_duration.get().as_secs_f32().to_string(),
+            ))?;
+        }
+        writer.write_event(JsonEvent::ObjectKey("children"))?;
+        writer.write_event(JsonEvent::StartArray)?;
+        for child in &self.children {
+            child.json_node(writer, with_stats)?;
+        }
+        writer.write_event(JsonEvent::EndArray)?;
+        writer.write_event(JsonEvent::EndObject)
+    }
+
+    fn node_label(&self) -> String {
+        match self.node.as_ref() {
+            FixedPointPlanNode::Extend {
+                expression,
+                variable,
+                ..
+            } => format!("Extend({expression} -> {variable})"),
+            FixedPointPlanNode::Filter { expression, .. } => format!("Filter({expression})"),
+
+            FixedPointPlanNode::HashJoin { .. } => "HashJoin".to_owned(),
+            FixedPointPlanNode::Project { mapping, .. } => {
+                format!(
+                    "Project({})",
+                    mapping
+                        .iter()
+                        .map(|(f, t)| if f.plain == t.plain {
+                            f.to_string()
+                        } else {
+                            format!("{f} -> {t}")
+                        })
+                        .collect::<Vec<_>>()
+                        .join(", ")
+                )
+            }
+            FixedPointPlanNode::QuadPattern {
+                subject,
+                predicate,
+                object,
+                graph_name,
+            } => format!("QuadPattern({subject} {predicate} {object} {graph_name})"),
+            FixedPointPlanNode::StaticBindings { variables, .. } => {
+                format!(
+                    "StaticBindings({})",
+                    variables
+                        .iter()
+                        .map(|v| v.to_string())
+                        .collect::<Vec<_>>()
+                        .join(", ")
+                )
+            }
+            FixedPointPlanNode::Union { .. } => "Union".to_owned(),
+            FixedPointPlanNode::FixedPoint { id, .. } => format!("FixedPoint{id}"),
+            FixedPointPlanNode::FixedPointEntry { id, .. } => format!("FixedPointEntry{id}"),
+        }
+    }
+}
+
+impl fmt::Debug for FixedPointPlanNodeWithStats {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut obj = f.debug_struct("Node");
         obj.field("name", &self.node_label());

lib/src/sparql/update.rs

@@ -123,6 +123,7 @@ impl<'a, 'b: 'a> SimpleUpdateEvaluator<'a, 'b> {
             algebra,
             false,
             &self.options.query_options.custom_functions,
+            None,
             !self.options.query_options.without_optimizations,
         )?;
         let evaluator = SimpleEvaluator::new(

testsuite/oxigraph-tests/sparql-reasoning/manifest.ttl

@@ -0,0 +1,48 @@
+@prefix rdf:   <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix :      <https://github.com/oxigraph/oxigraph/tests/sparql/manifest#> .
+@prefix rdfs:  <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix mf:    <http://www.w3.org/2001/sw/DataAccess/tests/test-manifest#> .
+@prefix qt:    <http://www.w3.org/2001/sw/DataAccess/tests/test-query#> .
+@prefix ox:    <https://github.com/oxigraph/oxigraph/tests#> .
+
+<>  rdf:type mf:Manifest ;
+    rdfs:label "Oxigraph SPARQL reasoning tests" ;
+    mf:entries
+    (
+    :simple_type_inheritance
+    :simple_fact
+    :with_graph_name
+    :simple_recursion
+    ) .
+
+:simple_type_inheritance rdf:type ox:SparqlRuleEvaluationTest ;
+    mf:name "Simple type inheritance" ;
+    mf:action
+         [ qt:query <simple_type_inheritance.rq> ;
+           qt:data  <simple_type_inheritance.ttl> ] ;
+    ox:rulesData <simple_type_inheritance.rr> ;
+    mf:result <simple_type_inheritance.srj> .
+
+:simple_fact rdf:type ox:SparqlRuleEvaluationTest ;
+    mf:name "Simple fact" ;
+    mf:action
+         [ qt:query <simple_fact.rq> ;
+           qt:data  <simple_fact.ttl> ] ;
+    ox:rulesData <simple_fact.rr> ;
+    mf:result <simple_fact.srj> .
+
+:with_graph_name rdf:type ox:SparqlRuleEvaluationTest ;
+    mf:name "Simple type inheritance" ;
+    mf:action
+         [ qt:query <with_graph_name.rq> ;
+           qt:graphData  <with_graph_name.ttl> ] ;
+    ox:rulesData <with_graph_name.rr> ;
+    mf:result <with_graph_name.srj> .
+
+:simple_recursion rdf:type ox:SparqlRuleEvaluationTest ;
+    mf:name "Simple recursion" ;
+    mf:action
+         [ qt:query <simple_recursion.rq> ;
+           qt:data  <simple_recursion.ttl> ] ;
+    ox:rulesData <simple_recursion.rr> ;
+    mf:result <simple_recursion.srj> .

testsuite/oxigraph-tests/sparql-reasoning/simple_fact.rq

@@ -0,0 +1,3 @@
+SELECT * WHERE {
+  ?s ?p ?o
+}

testsuite/oxigraph-tests/sparql-reasoning/simple_fact.rr

@@ -0,0 +1,3 @@
+PREFIX ex: <http://example.org/>
+
+IF {} THEN { ex:s ex:p ex:o }

testsuite/oxigraph-tests/sparql-reasoning/simple_fact.srj

@@ -0,0 +1,23 @@
+{
+  "head": {
+    "vars": ["s", "p", "o"]
+  },
+  "results": {
+    "bindings": [
+      {
+        "s": {
+          "type": "uri",
+          "value": "http://example.org/s"
+        },
+        "p": {
+          "type": "uri",
+          "value": "http://example.org/p"
+        },
+        "o": {
+          "type": "uri",
+          "value": "http://example.org/o"
+        }
+      }
+    ]
+  }
+}

testsuite/oxigraph-tests/sparql-reasoning/simple_recursion.rq

@@ -0,0 +1,5 @@
+PREFIX ex: <http://example.org/>
+
+SELECT DISTINCT * WHERE {
+ ?s ex:includedIn ?o
+}

testsuite/oxigraph-tests/sparql-reasoning/simple_recursion.rr

@@ -0,0 +1,3 @@
+PREFIX ex: <http://example.org/>
+
+IF { ?s ex:includedIn ?m . ?m ex:includedIn ?o } THEN { ?s ex:includedIn ?o }

testsuite/oxigraph-tests/sparql-reasoning/simple_recursion.srj

@@ -0,0 +1,69 @@
+{
+  "head": {
+    "vars": ["s", "o"]
+  },
+  "results": {
+    "bindings": [
+      {
+        "s": {
+          "type": "uri",
+          "value": "http://example.org/Bar"
+        },
+        "o": {
+          "type": "uri",
+          "value": "http://example.org/Foo"
+        }
+      },
+      {
+        "s": {
+          "type": "uri",
+          "value": "http://example.org/Baz"
+        },
+        "o": {
+          "type": "uri",
+          "value": "http://example.org/Foo"
+        }
+      },
+      {
+        "s": {
+          "type": "uri",
+          "value": "http://example.org/Baz"
+        },
+        "o": {
+          "type": "uri",
+          "value": "http://example.org/Bar"
+        }
+      },
+      {
+        "s": {
+          "type": "uri",
+          "value": "http://example.org/Baa"
+        },
+        "o": {
+          "type": "uri",
+          "value": "http://example.org/Foo"
+        }
+      },
+      {
+        "s": {
+          "type": "uri",
+          "value": "http://example.org/Baa"
+        },
+        "o": {
+          "type": "uri",
+          "value": "http://example.org/Bar"
+        }
+      },
+      {
+        "s": {
+          "type": "uri",
+          "value": "http://example.org/Baa"
+        },
+        "o": {
+          "type": "uri",
+          "value": "http://example.org/Baz"
+        }
+      }
+    ]
+  }
+}

testsuite/oxigraph-tests/sparql-reasoning/simple_recursion.ttl

@@ -0,0 +1,4 @@
+PREFIX ex: <http://example.org/>
+ex:Bar ex:includedIn ex:Foo .
+ex:Baz ex:includedIn ex:Bar .
+ex:Baa ex:includedIn ex:Baz .

testsuite/oxigraph-tests/sparql-reasoning/simple_type_inheritance.rq

@@ -0,0 +1,5 @@
+PREFIX ex: <http://example.org/>
+
+SELECT * WHERE {
+ ?s a ex:Bar
+}

testsuite/oxigraph-tests/sparql-reasoning/simple_type_inheritance.rr

@@ -0,0 +1,3 @@
+PREFIX ex: <http://example.org/>
+
+IF { ?s a ex:Foo } THEN { ?s a ex:Bar }

testsuite/oxigraph-tests/sparql-reasoning/simple_type_inheritance.srj

@@ -0,0 +1,15 @@
+{
+  "head": {
+    "vars": ["s"]
+  },
+  "results": {
+    "bindings": [
+      {
+        "s": {
+          "type": "uri",
+          "value": "http://example.org/s1"
+        }
+      }
+    ]
+  }
+}

testsuite/oxigraph-tests/sparql-reasoning/simple_type_inheritance.ttl

@@ -0,0 +1,2 @@
+PREFIX ex: <http://example.org/>
+ex:s1 a ex:Foo .

testsuite/oxigraph-tests/sparql-reasoning/with_graph_name.rq

@@ -0,0 +1,5 @@
+PREFIX ex: <http://example.org/>
+
+SELECT * WHERE {
+ GRAPH ?g { ?s a ex:Bar }
+}

testsuite/oxigraph-tests/sparql-reasoning/with_graph_name.rr

@@ -0,0 +1,3 @@
+PREFIX ex: <http://example.org/>
+
+IF { ?g a ex:Foo } THEN { ?g a ex:Bar }

testsuite/oxigraph-tests/sparql-reasoning/with_graph_name.srj

@@ -0,0 +1,19 @@
+{
+  "head": {
+    "vars": ["s", "g"]
+  },
+  "results": {
+    "bindings": [
+      {
+        "s": {
+          "type": "uri",
+          "value": "http://example.org/s1"
+        },
+        "g": {
+          "type": "uri",
+          "value": "https://github.com/oxigraph/oxigraph/tests/sparql-reasoning/with_graph_name.ttl"
+        }
+      }
+    ]
+  }
+}

testsuite/oxigraph-tests/sparql-reasoning/with_graph_name.ttl

@@ -0,0 +1,2 @@
+PREFIX ex: <http://example.org/>
+ex:s1 a ex:Foo .

testsuite/src/manifest.rs

@@ -19,6 +19,7 @@ pub struct Test {
     pub service_data: Vec<(String, String)>,
     pub result: Option<String>,
     pub result_graph_data: Vec<(NamedNode, String)>,
+    pub rules_data: Option<String>,
 }
 
 impl fmt::Display for Test {
@@ -255,6 +256,14 @@ impl TestManifest {
                 Some(_) => bail!("invalid result"),
                 None => (None, Vec::new()),
             };
+            let rules_data = if let Some(TermRef::NamedNode(n)) = self
+                .graph
+                .object_for_subject_predicate(&test_node, ox::RULES_DATA)
+            {
+                Some(n.as_str().to_owned())
+            } else {
+                None
+            };
             return Ok(Some(Test {
                 id: test_node,
                 kind,
@@ -268,6 +277,7 @@ impl TestManifest {
                 service_data,
                 result,
                 result_graph_data,
+                rules_data,
             }));
         }
     }

testsuite/src/sparql_evaluator.rs

@@ -67,6 +67,10 @@ pub fn register_sparql_tests(evaluator: &mut TestEvaluator) {
         "https://github.com/oxigraph/oxigraph/tests#NegativeTsvResultsSyntaxTest",
         evaluate_negative_tsv_result_syntax_test,
     );
+    evaluator.register(
+        "https://github.com/oxigraph/oxigraph/tests#SparqlRuleEvaluationTest",
+        evaluate_rule_evaluation_test,
+    );
 }
 
 fn evaluate_positive_syntax_test(test: &Test) -> Result<()> {
@@ -148,6 +152,12 @@ fn result_syntax_check(test: &Test, format: QueryResultsFormat) -> Result<()> {
 }
 
 fn evaluate_evaluation_test(test: &Test) -> Result<()> {
+    enum Mode {
+        Base,
+        WithoutOptimizer,
+        WithInferenceRules,
+    }
+
     let store = Store::new()?;
     if let Some(data) = &test.data {
         load_dataset_to_store(data, &store)?;
@@ -194,11 +204,12 @@ fn evaluate_evaluation_test(test: &Test) -> Result<()> {
         false
     };
 
-    for with_query_optimizer in [true, false] {
-        let mut options = options.clone();
-        if !with_query_optimizer {
-            options = options.without_optimizations();
-        }
+    for mode in [Mode::Base, Mode::WithoutOptimizer, Mode::WithInferenceRules] {
+        let options = match mode {
+            Mode::Base => options.clone(),
+            Mode::WithoutOptimizer => options.clone().without_optimizations(),
+            Mode::WithInferenceRules => options.clone().with_inference_rules(RuleSet::default()),
+        };
         let actual_results = store
             .query_opt(query.clone(), options)
             .map_err(|e| anyhow!("Failure to execute query of {test} with error: {e}"))?;
@@ -206,7 +217,12 @@ fn evaluate_evaluation_test(test: &Test) -> Result<()> {
 
         if !are_query_results_isomorphic(&expected_results, &actual_results) {
             bail!(
-                "Failure on {test}.\n{}\nParsed query:\n{}\nData:\n{store}\n",
+                "Failure{} on {test}.\n{}\nParsed query:\n{}\nData:\n{store}\n",
+                match mode {
+                    Mode::Base => "",
+                    Mode::WithoutOptimizer => " without optimizer",
+                    Mode::WithInferenceRules => " with inference rules",
+                },
                 results_diff(expected_results, actual_results),
                 Query::parse(&read_file_to_string(query_file)?, Some(query_file)).unwrap()
             );
@@ -286,6 +302,58 @@ fn evaluate_update_evaluation_test(test: &Test) -> Result<()> {
     }
 }
 
+fn evaluate_rule_evaluation_test(test: &Test) -> Result<()> {
+    let store = Store::new()?;
+    if let Some(data) = &test.data {
+        load_dataset_to_store(data, &store)?;
+    }
+    for (name, value) in &test.graph_data {
+        load_graph_to_store(value, &store, name)?;
+    }
+    let query_file = test
+        .query
+        .as_deref()
+        .ok_or_else(|| anyhow!("No action found for test {test}"))?;
+    let query = Query::parse(&read_file_to_string(query_file)?, Some(query_file))
+        .map_err(|e| anyhow!("Failure to parse query of {test} with error: {e}"))?;
+    let rule_file = test
+        .rules_data
+        .as_deref()
+        .ok_or_else(|| anyhow!("No rules data found for test {test}"))?;
+    let options = QueryOptions::default().with_inference_rules(
+        RuleSet::parse(&read_file_to_string(rule_file)?, Some(rule_file))
+            .map_err(|e| anyhow!("Failure to parse rule set of {test} with error: {e}"))?,
+    );
+
+    let expected_results = load_sparql_query_result(test.result.as_ref().unwrap())
+        .map_err(|e| anyhow!("Error constructing expected graph for {test}: {e}"))?;
+    let with_order = if let StaticQueryResults::Solutions { ordered, .. } = &expected_results {
+        *ordered
+    } else {
+        false
+    };
+
+    for with_query_optimizer in [true, false] {
+        let mut options = options.clone();
+        if !with_query_optimizer {
+            options = options.without_optimizations();
+        }
+        let actual_results = store
+            .query_opt(query.clone(), options)
+            .map_err(|e| anyhow!("Failure to execute query of {test} with error: {e}"))?;
+        let actual_results = StaticQueryResults::from_query_results(actual_results, with_order)?;
+
+        if !are_query_results_isomorphic(&expected_results, &actual_results) {
+            bail!(
+                "Failure on {test}.\n{}\nParsed query:\n{}\nData:\n{store}\n",
+                results_diff(expected_results, actual_results),
+                Query::parse(&read_file_to_string(query_file)?, Some(query_file)).unwrap()
+            );
+        }
+    }
+    Ok(())
+}
+
 fn load_sparql_query_result(url: &str) -> Result<StaticQueryResults> {
     if url.ends_with(".srx") {
         StaticQueryResults::from_query_results(

testsuite/src/vocab.rs

@@ -77,6 +77,7 @@ pub mod qt {
 
 pub mod ut {
     use oxigraph::model::NamedNodeRef;
+
     pub const DATA: NamedNodeRef<'_> =
         NamedNodeRef::new_unchecked("http://www.w3.org/2009/sparql/tests/test-update#data");
     pub const GRAPH_DATA: NamedNodeRef<'_> =
@@ -86,3 +87,10 @@ pub mod ut {
     pub const REQUEST: NamedNodeRef<'_> =
         NamedNodeRef::new_unchecked("http://www.w3.org/2009/sparql/tests/test-update#request");
 }
+
+pub mod ox {
+    use oxigraph::model::NamedNodeRef;
+
+    pub const RULES_DATA: NamedNodeRef<'_> =
+        NamedNodeRef::new_unchecked("https://github.com/oxigraph/oxigraph/tests#rulesData");
+}

testsuite/tests/oxigraph.rs

@@ -38,3 +38,10 @@ fn oxigraph_sparql_results_testsuite() -> Result<()> {
         "https://github.com/oxigraph/oxigraph/tests/sparql-results/manifest.ttl",
     ])
 }
+
+#[test]
+fn oxigraph_sparql_reasoning_testsuite() -> Result<()> {
+    run_testsuite(vec![
+        "https://github.com/oxigraph/oxigraph/tests/sparql-reasoning/manifest.ttl",
+    ])
+}

testsuite/tests/sparql.rs

@@ -67,6 +67,7 @@ fn sparql10_w3c_query_evaluation_testsuite() -> Result<()> {
         // We choose to simplify first the nested group patterns in OPTIONAL
         "http://www.w3.org/2001/sw/DataAccess/tests/data-r2/optional-filter/manifest#dawg-optional-filter-005-not-simplified",
         // This test relies on naive iteration on the input file
+        "http://www.w3.org/2001/sw/DataAccess/tests/data-r2/reduced/manifest#reduced-1",
         "http://www.w3.org/2001/sw/DataAccess/tests/data-r2/reduced/manifest#reduced-2"
     ])
 }