Function compile_relation

prqlc/prqlc/src/sql/pq/gen_query.rs:57–94

(relation: RelationAdapter, ctx: &mut Context)

}

fn compile_relation(relation: RelationAdapter, ctx: &mut Context) -> Result<pq::SqlRelation> {
    log::trace!("compiling relation {relation:#?}");

    Ok(match relation {
        RelationAdapter::Rq(rel) => {
            match rel.kind {
                // base case
                rq::RelationKind::Pipeline(pipeline) => {
                    // preprocess
                    let pipeline = preprocess::preprocess(pipeline, ctx)?;

                    // load names of output columns
                    ctx.anchor.load_names(&pipeline, rel.columns);

                    compile_pipeline(pipeline, ctx)?
                }

                rq::RelationKind::Literal(lit) => pq::SqlRelation::Literal(lit),
                rq::RelationKind::SString(items) => pq::SqlRelation::SString(items),
                rq::RelationKind::BuiltInFunction { name, args } => {
                    pq::SqlRelation::Operator { name, args }
                }

                // ref cannot be converted directly into query and does not need it's own CTE
                rq::RelationKind::ExternRef(_) => unreachable!(),
            }
        }

        RelationAdapter::Preprocessed(pipeline, columns) => {
            // load names of output columns
            ctx.anchor.load_names(&pipeline, columns);

            compile_pipeline(pipeline, ctx)?
        }

        RelationAdapter::Pq(rel) => rel,
    })
}

fn compile_pipeline(
    mut pipeline: Vec<pq::SqlTransform>,