Experimental parse-display POC

It may be possible to eliminate a lot of `fmt::Display` code by using [parse-display](https://github.com/frozenlib/parse-display/tree/master?tab=readme-ov-file#parse-display) crate. In the first iteration, it can replace many display traits for the simple cases of constants and formatted inner values. In the more advanced, it should be possible to format iterators, and if the issue I proposed get implemented, might even cover many of the `fmt_sse` functions. Note that I made a few unit tests for the migration purposes - just to see that the result is identical. We may want to remove at least some of them later on as being too trivial. One aspect that may need discussion: `write!(f, "{value}")` is not the same as `value.fmt(f)` because the first case creates a new `Formatter` instance, whereas the second case reuses the one passed as an argument to `Display::fmt` function. In some cases, it may break if formatter contains padding or number formatting configuration that will or won't be passed to the nested object. `parse-display` seem to always generate a new Formatter, but Oxigraph uses a lot of `.fmt` calls - which might actually be a bug.
11 months ago · ab0ee164fa
parent ea300e9081
commit ab0ee164fa
6 changed files with 253 additions and 113 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -1188,6 +1188,7 @@ dependencies = [
 "oxilangtag",
 "oxiri",
 "oxrdf",
+ "parse-display",
 "thiserror",
 "tokio",
 ]
@ -1215,6 +1216,31 @@ dependencies = [
 "windows-targets 0.48.5",
 ]

+[[package]]
+name = "parse-display"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06af5f9333eb47bd9ba8462d612e37a8328a5cb80b13f0af4de4c3b89f52dee5"
+dependencies = [
+ "parse-display-derive",
+ "regex",
+ "regex-syntax",
+]
+
+[[package]]
+name = "parse-display-derive"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc9252f259500ee570c75adcc4e317fa6f57a1e47747d622e0bf838002a7b790"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "regex",
+ "regex-syntax",
+ "structmeta",
+ "syn",
+]
+
 [[package]]
 name = "peg"
 version = "0.8.2"
@ -1761,6 +1787,7 @@ dependencies = [
 "oxilangtag",
 "oxiri",
 "oxrdf",
+ "parse-display",
 "peg",
 "rand",
 "thiserror",
@ -1794,6 +1821,29 @@ version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5ee073c9e4cd00e28217186dbe12796d692868f432bf2e97ee73bed0c56dfa01"

+[[package]]
+name = "structmeta"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e1575d8d40908d70f6fd05537266b90ae71b15dbbe7a8b7dffa2b759306d329"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "structmeta-derive",
+ "syn",
+]
+
+[[package]]
+name = "structmeta-derive"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "152a0b65a590ff6c3da95cabe2353ee04e6167c896b28e3b14478c2636c922fc"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "subtle"
 version = "2.5.0"
--- a/Cargo.toml
+++ b/Cargo.toml
@ -48,6 +48,7 @@ memchr = "2.5"
 oxhttp = "0.2.0-alpha.3"
 oxilangtag = "0.1"
 oxiri = "0.2.3-alpha.1"
+parse-display = "0.9.0"
 peg = "0.8"
 pkg-config = "0.3.25"
 predicates = ">=2.0, <4.0"
--- a/lib/oxttl/Cargo.toml
+++ b/lib/oxttl/Cargo.toml
@ -20,9 +20,10 @@ async-tokio = ["dep:tokio"]

 [dependencies]
 memchr.workspace = true
-oxrdf.workspace = true
-oxiri.workspace = true
 oxilangtag.workspace = true
+oxiri.workspace = true
+oxrdf.workspace = true
+parse-display.workspace = true
 thiserror.workspace = true
 tokio = { workspace = true, optional = true, features = ["io-util"] }

--- a/lib/oxttl/src/n3.rs
+++ b/lib/oxttl/src/n3.rs
@ -23,7 +23,8 @@ use std::io::Read;
 use tokio::io::AsyncRead;

 /// A N3 term i.e. a RDF `Term` or a `Variable`.
-#[derive(Eq, PartialEq, Debug, Clone, Hash)]
+#[derive(Eq, PartialEq, Debug, Clone, Hash, parse_display::Display)]
+#[display("{0}")]
 pub enum N3Term {
    NamedNode(NamedNode),
    BlankNode(BlankNode),
@ -33,17 +34,45 @@ pub enum N3Term {
    Variable(Variable),
 }

-impl fmt::Display for N3Term {
-    #[inline]
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Self::NamedNode(term) => term.fmt(f),
-            Self::BlankNode(term) => term.fmt(f),
-            Self::Literal(term) => term.fmt(f),
+#[cfg(test)]
+mod test_n3term {
+    use super::*;
+    #[test]
+    fn display() {
+        // This is a temporary migration test - we can remove most of these before merging
+        assert_eq!(
+            N3Term::NamedNode(NamedNode::new_unchecked("named")).to_string(),
+            "<named>"
+        );
+        assert_eq!(
+            N3Term::BlankNode(BlankNode::new_unchecked("blank")).to_string(),
+            "_:blank"
+        );
+        assert_eq!(
+            N3Term::Literal(Literal::new_simple_literal("literal")).to_string(),
+            r#""literal""#
+        );
+
        #[cfg(feature = "rdf-star")]
-            Self::Triple(term) => term.fmt(f),
-            Self::Variable(term) => term.fmt(f),
-        }
+        assert_eq!(
+            N3Term::Triple(Box::new(
+                Triple::new(
+                    NamedNode::new_unchecked("http://example.com/s"),
+                    NamedNode::new_unchecked("http://example.com/p"),
+                    Triple::new(
+                        NamedNode::new_unchecked("http://example.com/os"),
+                        NamedNode::new_unchecked("http://example.com/op"),
+                        NamedNode::new_unchecked("http://example.com/oo"),
+                    ),
+                )
+            ))
+            .to_string(),
+            "<http://example.com/s> <http://example.com/p> <<<http://example.com/os> <http://example.com/op> <http://example.com/oo>>>"
+        );
+        assert_eq!(
+            N3Term::Variable(Variable::new_unchecked("var")).to_string(),
+            "?var"
+        );
    }
 }

--- a/lib/spargebra/Cargo.toml
+++ b/lib/spargebra/Cargo.toml
@ -23,6 +23,7 @@ sep-0006 = []
 oxilangtag.workspace = true
 oxiri.workspace = true
 oxrdf.workspace = true
+parse-display.workspace = true
 peg.workspace = true
 rand.workspace = true
 thiserror.workspace = true
--- a/lib/spargebra/src/algebra.rs
+++ b/lib/spargebra/src/algebra.rs
@ -91,6 +91,30 @@ impl fmt::Display for PropertyPathExpression {
    }
 }

+/// The `display(with = ...)` will not work until this PR lands:
+///    https://github.com/frozenlib/parse-display/issues/36#issuecomment-1925367731
+///
+#[cfg(skip)]
+#[derive(Eq, PartialEq, Debug, Clone, Hash, parse_display::Display)]
+pub enum PropertyPathExpression {
+    #[display("{0}")]
+    NamedNode(NamedNode),
+    #[display("^({0})")]
+    Reverse(Box<Self>),
+    #[display("({0} / {1})")]
+    Sequence(Box<Self>, Box<Self>),
+    #[display("({0} | {1})")]
+    Alternative(Box<Self>, Box<Self>),
+    #[display("({0})*")]
+    ZeroOrMore(Box<Self>),
+    #[display("({0})+")]
+    OneOrMore(Box<Self>),
+    #[display("({0})?")]
+    ZeroOrOne(Box<Self>),
+    #[display("!({0})")]
+    NegatedPropertySet(#[display(with = delimiter(" | "))] Vec<NamedNode>),
+}
+
 impl From<NamedNode> for PropertyPathExpression {
    fn from(p: NamedNode) -> Self {
        Self::NamedNode(p)
@ -318,7 +342,8 @@ fn write_arg_list(
 }

 /// A function name.
-#[derive(Eq, PartialEq, Debug, Clone, Hash)]
+#[derive(Eq, PartialEq, Debug, Clone, Hash, parse_display::Display)]
+#[display(style = "UPPERCASE")]
 pub enum Function {
    Str,
    Lang,
@ -337,6 +362,7 @@ pub enum Function {
    Replace,
    UCase,
    LCase,
+    #[display("ENCODE_FOR_URI")]
    EncodeForUri,
    Contains,
    StrStarts,
@ -361,9 +387,13 @@ pub enum Function {
    Sha512,
    StrLang,
    StrDt,
+    #[display("isIRI")]
    IsIri,
+    #[display("isBLANK")]
    IsBlank,
+    #[display("isLITERAL")]
    IsLiteral,
+    #[display("isNUMERIC")]
    IsNumeric,
    Regex,
    #[cfg(feature = "rdf-star")]
@ -375,9 +405,11 @@ pub enum Function {
    #[cfg(feature = "rdf-star")]
    Object,
    #[cfg(feature = "rdf-star")]
+    #[display("isTRIPLE")]
    IsTriple,
    #[cfg(feature = "sep-0002")]
    Adjust,
+    #[display("{0}")]
    Custom(NamedNode),
 }

@ -448,69 +480,74 @@ impl Function {
    }
 }

-impl fmt::Display for Function {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Self::Str => f.write_str("STR"),
-            Self::Lang => f.write_str("LANG"),
-            Self::LangMatches => f.write_str("LANGMATCHES"),
-            Self::Datatype => f.write_str("DATATYPE"),
-            Self::Iri => f.write_str("IRI"),
-            Self::BNode => f.write_str("BNODE"),
-            Self::Rand => f.write_str("RAND"),
-            Self::Abs => f.write_str("ABS"),
-            Self::Ceil => f.write_str("CEIL"),
-            Self::Floor => f.write_str("FLOOR"),
-            Self::Round => f.write_str("ROUND"),
-            Self::Concat => f.write_str("CONCAT"),
-            Self::SubStr => f.write_str("SUBSTR"),
-            Self::StrLen => f.write_str("STRLEN"),
-            Self::Replace => f.write_str("REPLACE"),
-            Self::UCase => f.write_str("UCASE"),
-            Self::LCase => f.write_str("LCASE"),
-            Self::EncodeForUri => f.write_str("ENCODE_FOR_URI"),
-            Self::Contains => f.write_str("CONTAINS"),
-            Self::StrStarts => f.write_str("STRSTARTS"),
-            Self::StrEnds => f.write_str("STRENDS"),
-            Self::StrBefore => f.write_str("STRBEFORE"),
-            Self::StrAfter => f.write_str("STRAFTER"),
-            Self::Year => f.write_str("YEAR"),
-            Self::Month => f.write_str("MONTH"),
-            Self::Day => f.write_str("DAY"),
-            Self::Hours => f.write_str("HOURS"),
-            Self::Minutes => f.write_str("MINUTES"),
-            Self::Seconds => f.write_str("SECONDS"),
-            Self::Timezone => f.write_str("TIMEZONE"),
-            Self::Tz => f.write_str("TZ"),
-            Self::Now => f.write_str("NOW"),
-            Self::Uuid => f.write_str("UUID"),
-            Self::StrUuid => f.write_str("STRUUID"),
-            Self::Md5 => f.write_str("MD5"),
-            Self::Sha1 => f.write_str("SHA1"),
-            Self::Sha256 => f.write_str("SHA256"),
-            Self::Sha384 => f.write_str("SHA384"),
-            Self::Sha512 => f.write_str("SHA512"),
-            Self::StrLang => f.write_str("STRLANG"),
-            Self::StrDt => f.write_str("STRDT"),
-            Self::IsIri => f.write_str("isIRI"),
-            Self::IsBlank => f.write_str("isBLANK"),
-            Self::IsLiteral => f.write_str("isLITERAL"),
-            Self::IsNumeric => f.write_str("isNUMERIC"),
-            Self::Regex => f.write_str("REGEX"),
+#[cfg(test)]
+mod test_func {
+    use super::*;
+    #[test]
+    fn display() {
+        // This is a temporary migration test - we can remove most of these before merging
+        assert_eq!(Function::Str.to_string(), "STR");
+        assert_eq!(Function::Lang.to_string(), "LANG");
+        assert_eq!(Function::LangMatches.to_string(), "LANGMATCHES");
+        assert_eq!(Function::Datatype.to_string(), "DATATYPE");
+        assert_eq!(Function::Iri.to_string(), "IRI");
+        assert_eq!(Function::BNode.to_string(), "BNODE");
+        assert_eq!(Function::Rand.to_string(), "RAND");
+        assert_eq!(Function::Abs.to_string(), "ABS");
+        assert_eq!(Function::Ceil.to_string(), "CEIL");
+        assert_eq!(Function::Floor.to_string(), "FLOOR");
+        assert_eq!(Function::Round.to_string(), "ROUND");
+        assert_eq!(Function::Concat.to_string(), "CONCAT");
+        assert_eq!(Function::SubStr.to_string(), "SUBSTR");
+        assert_eq!(Function::StrLen.to_string(), "STRLEN");
+        assert_eq!(Function::Replace.to_string(), "REPLACE");
+        assert_eq!(Function::UCase.to_string(), "UCASE");
+        assert_eq!(Function::LCase.to_string(), "LCASE");
+        assert_eq!(Function::EncodeForUri.to_string(), "ENCODE_FOR_URI");
+        assert_eq!(Function::Contains.to_string(), "CONTAINS");
+        assert_eq!(Function::StrStarts.to_string(), "STRSTARTS");
+        assert_eq!(Function::StrEnds.to_string(), "STRENDS");
+        assert_eq!(Function::StrBefore.to_string(), "STRBEFORE");
+        assert_eq!(Function::StrAfter.to_string(), "STRAFTER");
+        assert_eq!(Function::Year.to_string(), "YEAR");
+        assert_eq!(Function::Month.to_string(), "MONTH");
+        assert_eq!(Function::Day.to_string(), "DAY");
+        assert_eq!(Function::Hours.to_string(), "HOURS");
+        assert_eq!(Function::Minutes.to_string(), "MINUTES");
+        assert_eq!(Function::Seconds.to_string(), "SECONDS");
+        assert_eq!(Function::Timezone.to_string(), "TIMEZONE");
+        assert_eq!(Function::Tz.to_string(), "TZ");
+        assert_eq!(Function::Now.to_string(), "NOW");
+        assert_eq!(Function::Uuid.to_string(), "UUID");
+        assert_eq!(Function::StrUuid.to_string(), "STRUUID");
+        assert_eq!(Function::Md5.to_string(), "MD5");
+        assert_eq!(Function::Sha1.to_string(), "SHA1");
+        assert_eq!(Function::Sha256.to_string(), "SHA256");
+        assert_eq!(Function::Sha384.to_string(), "SHA384");
+        assert_eq!(Function::Sha512.to_string(), "SHA512");
+        assert_eq!(Function::StrLang.to_string(), "STRLANG");
+        assert_eq!(Function::StrDt.to_string(), "STRDT");
+        assert_eq!(Function::IsIri.to_string(), "isIRI");
+        assert_eq!(Function::IsBlank.to_string(), "isBLANK");
+        assert_eq!(Function::IsLiteral.to_string(), "isLITERAL");
+        assert_eq!(Function::IsNumeric.to_string(), "isNUMERIC");
+        assert_eq!(Function::Regex.to_string(), "REGEX");
        #[cfg(feature = "rdf-star")]
-            Self::Triple => f.write_str("TRIPLE"),
+        assert_eq!(Function::Triple.to_string(), "TRIPLE");
        #[cfg(feature = "rdf-star")]
-            Self::Subject => f.write_str("SUBJECT"),
+        assert_eq!(Function::Subject.to_string(), "SUBJECT");
        #[cfg(feature = "rdf-star")]
-            Self::Predicate => f.write_str("PREDICATE"),
+        assert_eq!(Function::Predicate.to_string(), "PREDICATE");
        #[cfg(feature = "rdf-star")]
-            Self::Object => f.write_str("OBJECT"),
+        assert_eq!(Function::Object.to_string(), "OBJECT");
        #[cfg(feature = "rdf-star")]
-            Self::IsTriple => f.write_str("isTRIPLE"),
+        assert_eq!(Function::IsTriple.to_string(), "isTRIPLE");
        #[cfg(feature = "sep-0002")]
-            Self::Adjust => f.write_str("ADJUST"),
-            Self::Custom(iri) => iri.fmt(f),
-        }
+        assert_eq!(Function::Adjust.to_string(), "ADJUST");
+        assert_eq!(
+            Function::Custom(NamedNode::new("http://example.com/foo").unwrap()).to_string(),
+            "<http://example.com/foo>"
+        );
    }
 }

@ -1217,7 +1254,8 @@ impl fmt::Display for AggregateExpression {
 }

 /// An aggregate function name.
-#[derive(Eq, PartialEq, Debug, Clone, Hash)]
+#[derive(Eq, PartialEq, Debug, Clone, Hash, parse_display::Display)]
+#[display(style = "SNAKE_CASE")]
 pub enum AggregateFunction {
    /// [Count](https://www.w3.org/TR/sparql11-query/#defn_aggCount) with *.
    Count,
@ -1230,11 +1268,11 @@ pub enum AggregateFunction {
    /// [Max](https://www.w3.org/TR/sparql11-query/#defn_aggMax).
    Max,
    /// [GroupConcat](https://www.w3.org/TR/sparql11-query/#defn_aggGroupConcat).
-    GroupConcat {
-        separator: Option<String>,
-    },
+    #[display("{}")]
+    GroupConcat { separator: Option<String> },
    /// [Sample](https://www.w3.org/TR/sparql11-query/#defn_aggSample).
    Sample,
+    #[display("{0}")]
    Custom(NamedNode),
 }

@ -1254,23 +1292,36 @@ impl AggregateFunction {
    }
 }

-impl fmt::Display for AggregateFunction {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Self::Count => f.write_str("COUNT"),
-            Self::Sum => f.write_str("SUM"),
-            Self::Avg => f.write_str("AVG"),
-            Self::Min => f.write_str("MIN"),
-            Self::Max => f.write_str("MAX"),
-            Self::GroupConcat { .. } => f.write_str("GROUP_CONCAT"),
-            Self::Sample => f.write_str("SAMPLE"),
-            Self::Custom(iri) => iri.fmt(f),
+#[cfg(test)]
+mod test_agg {
+    use super::*;
+    #[test]
+    fn display() {
+        // This is a temporary migration test - we can remove most of these before merging
+        assert_eq!(AggregateFunction::Count.to_string(), "COUNT");
+        assert_eq!(AggregateFunction::Sum.to_string(), "SUM");
+        assert_eq!(AggregateFunction::Avg.to_string(), "AVG");
+        assert_eq!(AggregateFunction::Min.to_string(), "MIN");
+        assert_eq!(AggregateFunction::Max.to_string(), "MAX");
+        assert_eq!(
+            AggregateFunction::GroupConcat {
+                separator: Some("foo".to_owned())
            }
+            .to_string(),
+            "GROUP_CONCAT"
+        );
+        assert_eq!(AggregateFunction::Sample.to_string(), "SAMPLE");
+        assert_eq!(
+            AggregateFunction::Custom(NamedNode::new("http://example.com/foo").unwrap())
+                .to_string(),
+            "<http://example.com/foo>"
+        );
    }
 }

 /// An ordering comparator used by [`GraphPattern::OrderBy`].
-#[derive(Eq, PartialEq, Debug, Clone, Hash)]
+#[derive(Eq, PartialEq, Debug, Clone, Hash, parse_display::Display)]
+#[display("{}({0})", style = "UPPERCASE")]
 pub enum OrderExpression {
    /// Ascending order
    Asc(Expression),
@ -1296,12 +1347,26 @@ impl OrderExpression {
    }
 }

-impl fmt::Display for OrderExpression {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Self::Asc(e) => write!(f, "ASC({e})"),
-            Self::Desc(e) => write!(f, "DESC({e})"),
-        }
+#[cfg(test)]
+mod test_order_expr {
+    use super::*;
+    #[test]
+    fn display() {
+        // This is a temporary migration test - we can remove most of these before merging
+        assert_eq!(
+            OrderExpression::Asc(Expression::NamedNode(
+                NamedNode::new("http://example.com/foo").unwrap()
+            ))
+            .to_string(),
+            "ASC(<http://example.com/foo>)"
+        );
+        assert_eq!(
+            OrderExpression::Desc(Expression::NamedNode(
+                NamedNode::new("http://example.com/bar").unwrap()
+            ))
+            .to_string(),
+            "DESC(<http://example.com/bar>)"
+        );
    }
 }

@ -1351,11 +1416,15 @@ impl fmt::Display for QueryDataset {
 /// A target RDF graph for update operations.
 ///
 /// Could be a specific graph, all named graphs or the complete dataset.
-#[derive(Eq, PartialEq, Debug, Clone, Hash)]
+#[derive(Eq, PartialEq, Debug, Clone, Hash, parse_display::Display)]
 pub enum GraphTarget {
+    #[display("GRAPH {0}")]
    NamedNode(NamedNode),
+    #[display("DEFAULT")]
    DefaultGraph,
+    #[display("NAMED")]
    NamedGraphs,
+    #[display("ALL")]
    AllGraphs,
 }

@ -1371,17 +1440,6 @@ impl GraphTarget {
    }
 }

-impl fmt::Display for GraphTarget {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Self::NamedNode(node) => write!(f, "GRAPH {node}"),
-            Self::DefaultGraph => f.write_str("DEFAULT"),
-            Self::NamedGraphs => f.write_str("NAMED"),
-            Self::AllGraphs => f.write_str("ALL"),
-        }
-    }
-}
-
 impl From<NamedNode> for GraphTarget {
    fn from(node: NamedNode) -> Self {
        Self::NamedNode(node)