refactor: add AliasedProvableExprPlan (#35)

# Rationale for this change
In new versions of `GroupByExpr` tuple `(ProvableExprPlan<C>,
Identifier)` is extremely common. We may as well add a struct for this.
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# What changes are included in this PR?
- add `AliasedProvableExprPlan`
- one instance of minor typo fix
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# Are these changes tested?
Existing tests should pass
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crates/proof-of-sql/src/sql/ast/add_subtract_expr_test.rs

@@ -34,10 +34,7 @@ fn we_can_prove_a_typical_add_subtract_query() {
         vec![
             col_expr_plan(t, "a", &accessor),
             col_expr_plan(t, "c", &accessor),
-            (
-                add(column(t, "b", &accessor), const_bigint(4)),
-                "res".parse().unwrap(),
-            ),
+            aliased_plan(add(column(t, "b", &accessor), const_bigint(4)), "res"),
             col_expr_plan(t, "d", &accessor),
         ],
         tab(t),
@@ -72,15 +69,15 @@ fn we_can_prove_a_typical_add_subtract_query_with_decimals() {
     let ast = dense_filter(
         vec![
             col_expr_plan(t, "a", &accessor),
-            (
+            aliased_plan(
                 add(
                     add(
                         add(column(t, "a", &accessor), column(t, "b", &accessor)),
                         column(t, "c", &accessor),
                     ),
                     const_decimal75(2, 1, 4),
                 ),
-                "c".parse().unwrap(),
+                "c",
             ),
             col_expr_plan(t, "d", &accessor),
         ],
@@ -124,9 +121,9 @@ fn result_expr_can_overflow() {
     let t = "sxt.t".parse().unwrap();
     let accessor = OwnedTableTestAccessor::<InnerProductProof>::new_from_table(t, data, 0, ());
     let ast: ProofPlan<RistrettoPoint> = dense_filter(
-        vec![(
+        vec![aliased_plan(
             add(column(t, "a", &accessor), column(t, "b", &accessor)),
-            "c".parse().unwrap(),
+            "c",
         )],
         tab(t),
         equal(column(t, "b", &accessor), const_bigint(1)),
@@ -149,9 +146,9 @@ fn overflow_in_nonselected_rows_doesnt_error_out() {
     let t = "sxt.t".parse().unwrap();
     let accessor = OwnedTableTestAccessor::<InnerProductProof>::new_from_table(t, data, 0, ());
     let ast: ProofPlan<RistrettoPoint> = dense_filter(
-        vec![(
+        vec![aliased_plan(
             add(column(t, "a", &accessor), column(t, "b", &accessor)),
-            "c".parse().unwrap(),
+            "c",
         )],
         tab(t),
         equal(column(t, "b", &accessor), const_bigint(0)),
@@ -197,13 +194,13 @@ fn result_expr_can_overflow_more() {
     let accessor = OwnedTableTestAccessor::<InnerProductProof>::new_from_table(t, data, 0, ());
     let ast: ProofPlan<RistrettoPoint> = dense_filter(
         vec![
-            (
+            aliased_plan(
                 add(column(t, "a", &accessor), column(t, "b", &accessor)),
-                "c".parse().unwrap(),
+                "c",
             ),
-            (
+            aliased_plan(
                 subtract(column(t, "a", &accessor), column(t, "b", &accessor)),
-                "d".parse().unwrap(),
+                "d",
             ),
         ],
         tab(t),
@@ -251,12 +248,12 @@ fn test_random_tables_with_given_offset(offset: usize) {
         let ast = dense_filter(
             vec![
                 col_expr_plan(t, "d", &accessor),
-                (
+                aliased_plan(
                     subtract(
                         add(column(t, "a", &accessor), column(t, "c", &accessor)),
                         const_int128(4),
                     ),
-                    "f".parse().unwrap(),
+                    "f",
                 ),
             ],
             tab(t),

crates/proof-of-sql/src/sql/ast/aliased_provable_expr_plan.rs

@@ -0,0 +1,11 @@
+use super::ProvableExprPlan;
+use crate::base::commitment::Commitment;
+use proof_of_sql_parser::Identifier;
+use serde::{Deserialize, Serialize};
+
+/// A `ProvableExprPlan` with an alias.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AliasedProvableExprPlan<C: Commitment> {
+    pub expr: ProvableExprPlan<C>,
+    pub alias: Identifier,
+}

crates/proof-of-sql/src/sql/ast/dense_filter_expr.rs

@@ -1,8 +1,6 @@
 use super::{
     dense_filter_util::{fold_columns, fold_vals},
-    filter_columns,
-    provable_expr_plan::ProvableExprPlan,
-    ProvableExpr, TableExpr,
+    filter_columns, AliasedProvableExprPlan, ProvableExpr, ProvableExprPlan, TableExpr,
 };
 use crate::{
     base::{
@@ -23,7 +21,6 @@ use crate::{
 use bumpalo::Bump;
 use core::iter::repeat_with;
 use num_traits::{One, Zero};
-use proof_of_sql_parser::Identifier;
 use serde::{Deserialize, Serialize};
 use std::{collections::HashSet, marker::PhantomData};
 
@@ -35,7 +32,7 @@ use std::{collections::HashSet, marker::PhantomData};
 /// This differs from the [`FilterExpr`] in that the result is not a sparse table.
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
 pub struct OstensibleDenseFilterExpr<C: Commitment, H: ProverHonestyMarker> {
-    pub(super) aliased_results: Vec<(ProvableExprPlan<C>, Identifier)>,
+    pub(super) aliased_results: Vec<AliasedProvableExprPlan<C>>,
     pub(super) table: TableExpr,
     pub(super) where_clause: ProvableExprPlan<C>,
     phantom: PhantomData<H>,
@@ -44,7 +41,7 @@ pub struct OstensibleDenseFilterExpr<C: Commitment, H: ProverHonestyMarker> {
 impl<C: Commitment, H: ProverHonestyMarker> OstensibleDenseFilterExpr<C, H> {
     /// Creates a new dense_filter expression.
     pub fn new(
-        aliased_results: Vec<(ProvableExprPlan<C>, Identifier)>,
+        aliased_results: Vec<AliasedProvableExprPlan<C>>,
         table: TableExpr,
         where_clause: ProvableExprPlan<C>,
     ) -> Self {
@@ -68,7 +65,7 @@ where
     ) -> Result<(), ProofError> {
         self.where_clause.count(builder)?;
         for aliased_expr in self.aliased_results.iter() {
-            aliased_expr.0.count(builder)?;
+            aliased_expr.expr.count(builder)?;
             builder.count_result_columns(1);
         }
         builder.count_intermediate_mles(2);
@@ -99,7 +96,7 @@ where
         let columns_evals = Vec::from_iter(
             self.aliased_results
                 .iter()
-                .map(|(expr, _)| expr.verifier_evaluate(builder, accessor))
+                .map(|aliased_expr| aliased_expr.expr.verifier_evaluate(builder, accessor))
                 .collect::<Result<Vec<_>, _>>()?,
         );
         // 3. indexes
@@ -128,15 +125,15 @@ where
     fn get_column_result_fields(&self) -> Vec<ColumnField> {
         self.aliased_results
             .iter()
-            .map(|(expr, alias)| ColumnField::new(*alias, expr.data_type()))
+            .map(|aliased_expr| ColumnField::new(aliased_expr.alias, aliased_expr.expr.data_type()))
             .collect()
     }
 
     fn get_column_references(&self) -> HashSet<ColumnRef> {
         let mut columns = HashSet::new();
 
-        for (col, _) in self.aliased_results.iter() {
-            col.get_column_references(&mut columns);
+        for aliased_expr in self.aliased_results.iter() {
+            aliased_expr.expr.get_column_references(&mut columns);
         }
 
         self.where_clause.get_column_references(&mut columns);
@@ -165,11 +162,11 @@ impl<C: Commitment> ProverEvaluate<C::Scalar> for DenseFilterExpr<C> {
             .expect("selection is not boolean");
 
         // 2. columns
-        let columns = Vec::from_iter(
-            self.aliased_results
-                .iter()
-                .map(|(expr, _)| expr.result_evaluate(builder.table_length(), alloc, accessor)),
-        );
+        let columns = Vec::from_iter(self.aliased_results.iter().map(|aliased_expr| {
+            aliased_expr
+                .expr
+                .result_evaluate(builder.table_length(), alloc, accessor)
+        }));
         // Compute filtered_columns and indexes
         let (filtered_columns, result_len) = filter_columns(alloc, &columns, selection);
         // 3. set indexes
@@ -200,7 +197,7 @@ impl<C: Commitment> ProverEvaluate<C::Scalar> for DenseFilterExpr<C> {
         let columns = Vec::from_iter(
             self.aliased_results
                 .iter()
-                .map(|(expr, _)| expr.prover_evaluate(builder, alloc, accessor)),
+                .map(|aliased_expr| aliased_expr.expr.prover_evaluate(builder, alloc, accessor)),
         );
         // Compute filtered_columns and indexes
         let (filtered_columns, result_len) = filter_columns(alloc, &columns, selection);

crates/proof-of-sql/src/sql/ast/dense_filter_expr_test.rs

@@ -1,9 +1,6 @@
 use crate::{
     base::{database::owned_table_utility::*, math::decimal::Precision},
-    sql::ast::{
-        test_utility::{and, not, or},
-        ProvableExprPlan,
-    },
+    sql::ast::{test_utility::*, ProvableExprPlan},
 };
 use crate::{
     base::{
@@ -46,21 +43,21 @@ fn we_can_correctly_fetch_the_query_result_schema() {
     let b = Identifier::try_new("b").unwrap();
     let provable_ast = DenseFilterExpr::<RistrettoPoint>::new(
         vec![
-            (
+            aliased_plan(
                 ProvableExprPlan::Column(ColumnExpr::new(ColumnRef::new(
                     table_ref,
                     a,
                     ColumnType::BigInt,
                 ))),
-                a,
+                "a",
             ),
-            (
+            aliased_plan(
                 ProvableExprPlan::Column(ColumnExpr::new(ColumnRef::new(
                     table_ref,
                     b,
                     ColumnType::BigInt,
                 ))),
-                b,
+                "b",
             ),
         ],
         TableExpr { table_ref },
@@ -98,21 +95,21 @@ fn we_can_correctly_fetch_all_the_referenced_columns() {
     let f = Identifier::try_new("f").unwrap();
     let provable_ast = DenseFilterExpr::new(
         vec![
-            (
+            aliased_plan(
                 ProvableExprPlan::Column(ColumnExpr::new(ColumnRef::new(
                     table_ref,
                     a,
                     ColumnType::BigInt,
                 ))),
-                a,
+                "a",
             ),
-            (
+            aliased_plan(
                 ProvableExprPlan::Column(ColumnExpr::new(ColumnRef::new(
                     table_ref,
                     f,
                     ColumnType::BigInt,
                 ))),
-                f,
+                "f",
             ),
         ],
         TableExpr { table_ref },
@@ -438,10 +435,10 @@ fn we_can_prove_a_dense_filter() {
             col_expr_plan(t, "c", &accessor),
             col_expr_plan(t, "d", &accessor),
             col_expr_plan(t, "e", &accessor),
-            (const_int128(105), "const".parse().unwrap()),
-            (
+            aliased_plan(const_int128(105), "const"),
+            aliased_plan(
                 equal(column(t, "b", &accessor), column(t, "c", &accessor)),
-                "bool".parse().unwrap(),
+                "bool",
             ),
         ],
         tab(t),

crates/proof-of-sql/src/sql/ast/dense_filter_expr_test_dishonest_prover.rs

@@ -48,11 +48,11 @@ impl ProverEvaluate<Curve25519Scalar> for DishonestDenseFilterExpr<RistrettoPoin
             .as_boolean()
             .expect("selection is not boolean");
         // 2. columns
-        let columns = Vec::from_iter(
-            self.aliased_results
-                .iter()
-                .map(|(expr, _)| expr.result_evaluate(builder.table_length(), alloc, accessor)),
-        );
+        let columns = Vec::from_iter(self.aliased_results.iter().map(|aliased_expr| {
+            aliased_expr
+                .expr
+                .result_evaluate(builder.table_length(), alloc, accessor)
+        }));
         // Compute filtered_columns and indexes
         let (filtered_columns, result_len) = filter_columns(alloc, &columns, selection);
         let filtered_columns = tamper_column(alloc, filtered_columns);
@@ -87,7 +87,7 @@ impl ProverEvaluate<Curve25519Scalar> for DishonestDenseFilterExpr<RistrettoPoin
         let columns = Vec::from_iter(
             self.aliased_results
                 .iter()
-                .map(|(expr, _)| expr.prover_evaluate(builder, alloc, accessor)),
+                .map(|aliased_expr| aliased_expr.expr.prover_evaluate(builder, alloc, accessor)),
         );
         // Compute filtered_columns and indexes
         let (filtered_columns, result_len) = filter_columns(alloc, &columns, selection);

crates/proof-of-sql/src/sql/ast/mod.rs

@@ -1,4 +1,7 @@
 //! This module proves provable ASTs.
+mod aliased_provable_expr_plan;
+pub(crate) use aliased_provable_expr_plan::AliasedProvableExprPlan;
+
 mod filter_result_expr;
 pub(crate) use filter_result_expr::FilterResultExpr;