add 'filter' command

Cargo.toml

@@ -18,7 +18,7 @@ version = "0.9.0"
 features = ["file_url", "http_client", "jsonld", "sparql", "xml"]
 # path = "../sophia_rs/sophia"
 git = "https://github.com/pchampin/sophia_rs.git"
-rev = "00d3cf98"
+rev = "3b2a6dc"
 
 [[bin]]
 name = "sop"

src/filter.rs

@@ -0,0 +1,51 @@
+use std::convert::Infallible;
+
+use anyhow::Result;
+use sophia::{
+    api::{quad::Spog, sparql::SparqlDataset},
+    sparql::{SparqlQuery, SparqlWrapper, SparqlWrapperError},
+    term::ArcTerm,
+};
+
+use crate::common::{pipe::PipeSubcommand, quad_handler::QuadHandler, quad_iter::QuadIter};
+
+/// Keep only quads that match a SPARQL expression.
+///
+/// In the expression, ?s, ?p, ?o and ?g are bound to the subject,
+/// predicare, object and graph name of the quad, respectively.
+#[derive(clap::Args, Clone, Debug)]
+pub struct Args {
+    /// SPARQL expression
+    #[arg()]
+    expression: String,
+
+    #[command(subcommand)]
+    pipeline: Option<PipeSubcommand>,
+}
+
+pub fn run(mut quads: QuadIter, args: Args) -> Result<()> {
+    log::trace!("filter args: {args:#?}");
+
+    let ask_query = make_query(&args.expression)?;
+    let handler = QuadHandler::new(args.pipeline);
+    handler.handle_quads(QuadIter::new(quads.into_iter().filter_map(|res| {
+        let Ok(quad) = res else {
+            return Some(res); // always keep errors
+        };
+        let dataset = [quad];
+        let sparql = SparqlWrapper(&dataset[..]);
+        let resp = sparql.query(&ask_query).ok()?.into_boolean();
+        let [quad] = dataset;
+        resp.then(|| Ok(quad))
+    })))
+}
+
+fn make_query(
+    expression: &str,
+) -> Result<SparqlQuery<[Spog<ArcTerm>]>, SparqlWrapperError<Infallible>> {
+    let empty_dataset: [Spog<ArcTerm>; 0] = [];
+    let sparql = SparqlWrapper(&empty_dataset[..]);
+    sparql.prepare_query(&format!(
+        "ASK {{ {{ ?s ?p ?o }} UNION {{ GRAPH ?g {{ ?s ?p ?o }} }} FILTER ({expression}) }}"
+    ))
+}

src/main.rs

@@ -5,6 +5,7 @@ use common::quad_iter::QuadIter;
 
 mod canonicalize;
 mod common;
+mod filter;
 mod merge_default_graph;
 mod parse;
 mod query;
@@ -42,6 +43,8 @@ enum SourceSubcommand {
 enum SinkSubcommand {
     #[command(visible_aliases=["c", "c14n"], aliases=["ca", "can"])]
     Canonicalize(canonicalize::Args),
+    #[command(visible_aliases=["f"], aliases=["fi", "fil"])]
+    Filter(filter::Args),
     #[command(visible_aliases=["m", "merge"], aliases=["me", "mer"])]
     MergeDefaultGraph(merge_default_graph::Args),
     #[command(visible_aliases=["q"], aliases=["qu", "que"])]
@@ -54,6 +57,7 @@ impl SinkSubcommand {
     pub fn handle_quads(self, quads: QuadIter) -> Result<()> {
         match self {
             Self::Canonicalize(args) => canonicalize::run(quads, args),
+            Self::Filter(args) => filter::run(quads, args),
             Self::MergeDefaultGraph(args) => merge_default_graph::run(quads, args),
             Self::Query(args) => query::run(quads, args),
             Self::Serialize(args) => serialize::run(quads, args),