feat: Allow array of fields on public output

Cargo.toml

@@ -12,7 +12,7 @@ ark-ff = "0.3.0"
 ark-bls12-381 = "0.3.0"                                                                                         # bls12-381 curve for r1cs backend
 ark-bn254 = "0.3.0"                                                                                             # bn128 curve for r1cs backend
 ark-serialize = "0.3.0"                                                                                         # serialization of arkworks types
-educe = { version = "0.6", default-features = false, features = ["Hash", "PartialEq"] }
+educe = { version = "0.6", default-features = false, features = ["Hash", "PartialEq", "PartialOrd"] }
 ena = "0.14.0"                                                                                                  # union-find implementation for the wiring
 num-bigint = "0.4.3"                                                                                            # big int library
 camino = "1.1.1"                                                                                                # to replace Path and PathBuf

examples/fixture/asm/kimchi/public_output_array.asm

@@ -0,0 +1,17 @@
+@ noname.0.7.0
+
+DoubleGeneric<1>
+DoubleGeneric<1>
+DoubleGeneric<1>
+DoubleGeneric<1,1,-1>
+DoubleGeneric<1,0,0,0,-2>
+DoubleGeneric<1,0,-1,0,6>
+DoubleGeneric<0,0,-1,1>
+DoubleGeneric<1,-1>
+DoubleGeneric<1,-1>
+(0,0) -> (7,0)
+(1,0) -> (8,0)
+(2,0) -> (3,1) -> (6,1)
+(3,2) -> (4,0) -> (5,0) -> (6,0)
+(5,2) -> (7,1)
+(6,2) -> (8,1)

examples/fixture/asm/kimchi/types_array_output.asm

@@ -0,0 +1,28 @@
+@ noname.0.7.0
+
+DoubleGeneric<1>
+DoubleGeneric<1>
+DoubleGeneric<1>
+DoubleGeneric<1>
+DoubleGeneric<1>
+DoubleGeneric<1>
+DoubleGeneric<2,0,-1>
+DoubleGeneric<2,0,-1>
+DoubleGeneric<2,0,-1>
+DoubleGeneric<1,-1>
+DoubleGeneric<2,0,-1>
+DoubleGeneric<1,-1>
+DoubleGeneric<1,-1>
+DoubleGeneric<1,-1>
+DoubleGeneric<1,-1>
+DoubleGeneric<1,-1>
+(0,0) -> (12,0)
+(1,0) -> (13,0)
+(2,0) -> (14,0)
+(3,0) -> (15,0)
+(4,0) -> (6,0) -> (8,0) -> (14,1)
+(5,0) -> (7,0) -> (10,0) -> (13,1)
+(6,2) -> (9,1) -> (12,1)
+(7,2) -> (11,1) -> (15,1)
+(8,2) -> (9,0)
+(10,2) -> (11,0)

examples/fixture/asm/r1cs/public_output_array.asm

@@ -0,0 +1,6 @@
+@ noname.0.7.0
+
+2 == (v_3 + v_4) * (1)
+v_5 == (v_3 + v_4) * (v_3)
+v_3 + v_4 + 6 == (v_1) * (1)
+v_5 == (v_2) * (1)

examples/fixture/asm/r1cs/types_array_output.asm

@@ -0,0 +1,8 @@
+@ noname.0.7.0
+
+2 * v_5 == (2 * v_5) * (1)
+2 * v_6 == (2 * v_6) * (1)
+2 * v_5 == (v_1) * (1)
+v_6 == (v_2) * (1)
+v_5 == (v_3) * (1)
+2 * v_6 == (v_4) * (1)

examples/public_output_array.no

@@ -0,0 +1,6 @@
+fn main(pub public_input: Field, private_input: Field) -> [Field; 2] {
+    let xx = private_input + public_input;
+    assert_eq(xx, 2);
+    let yy = xx + 6;
+    return [yy, xx * public_input];
+}

examples/types_array_output.no

@@ -0,0 +1,21 @@
+struct Thing {
+    xx: Field,
+    yy: Field,
+}
+
+fn main(pub xx: Field, pub yy: Field) -> [Thing; 2] {
+    let thing1 = Thing {
+        xx: xx * 2,
+        yy: yy,
+    };
+    let thing2 = Thing {
+        xx: xx,
+        yy: yy * 2,
+    };
+    let things = [thing1, thing2];
+
+    assert_eq(things[1].xx * 2, things[0].xx);
+    assert_eq(things[0].yy * 2, things[1].yy);
+
+    return things;
+}

src/backends/kimchi/mod.rs

@@ -2,8 +2,9 @@ pub mod asm;
 pub mod builtin;
 pub mod prover;
 
+use educe::Educe;
 use std::{
-    collections::{HashMap, HashSet},
+    collections::{BTreeMap, HashMap, HashSet},
     fmt::Write,
     ops::Neg as _,
 };
@@ -243,9 +244,11 @@ impl KimchiVesta {
     }
 }
 
-#[derive(Default, Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[derive(Default, Clone, Copy, Debug, Eq, Hash, Serialize, Deserialize, PartialEq, Ord, Educe)]
+#[educe(PartialOrd)]
 pub struct KimchiCellVar {
     index: usize,
+    #[educe(PartialOrd(ignore))]
     pub span: Span,
 }
 
@@ -391,7 +394,7 @@ impl Backend for KimchiVesta {
 
         let mut witness = vec![];
         // compute each rows' vars, except for the deferred ones (public output)
-        let mut public_outputs_vars: HashMap<KimchiCellVar, Vec<(usize, usize)>> = HashMap::new();
+        let mut public_outputs_vars: BTreeMap<KimchiCellVar, Vec<(usize, usize)>> = BTreeMap::new();
 
         // calculate witness except for public outputs
         for (row, row_of_vars) in self.witness_table.iter().enumerate() {

src/circuit_writer/mod.rs

@@ -163,12 +163,9 @@ impl<B: Backend> CircuitWriter<B> {
 
         // create public output
         if let Some(typ) = &function.sig.return_type {
-            if typ.kind != TyKind::Field {
-                unimplemented!();
-            }
-
-            // create it
-            circuit_writer.add_public_outputs(1, typ.span);
+            // whatever is the size of return type, we need to add that many public outputs
+            let size_of = circuit_writer.size_of(&typ.kind);
+            circuit_writer.add_public_outputs(size_of, typ.span);
         }
 
         // public inputs should be handled first

src/tests/examples.rs

@@ -424,3 +424,39 @@ fn test_literals(#[case] backend: BackendKind) -> miette::Result<()> {
 
     Ok(())
 }
+
+#[rstest]
+#[case::kimchi_vesta(BackendKind::KimchiVesta(KimchiVesta::new(false)))]
+#[case::r1cs(BackendKind::R1csBls12_381(R1CS::new()))]
+fn test_public_output_array(#[case] backend: BackendKind) -> miette::Result<()> {
+    let public_inputs = r#"{"public_input": "1"}"#;
+    let private_inputs = r#"{"private_input": "1"}"#;
+
+    test_file(
+        "public_output_array",
+        public_inputs,
+        private_inputs,
+        vec!["8", "2"],
+        backend,
+    )?;
+
+    Ok(())
+}
+
+#[rstest]
+#[case::kimchi_vesta(BackendKind::KimchiVesta(KimchiVesta::new(false)))]
+#[case::r1cs(BackendKind::R1csBls12_381(R1CS::new()))]
+fn test_types_array_output(#[case] backend: BackendKind) -> miette::Result<()> {
+    let public_inputs = r#"{"xx": "1", "yy": "4"}"#;
+    let private_inputs = r#"{}"#;
+
+    test_file(
+        "types_array_output",
+        public_inputs,
+        private_inputs,
+        vec!["2", "4", "1", "8"], // 2x, y, x, 2y
+        backend,
+    )?;
+
+    Ok(())
+}

src/type_checker/mod.rs

@@ -379,14 +379,21 @@ impl<B: Backend> TypeChecker<B> {
                     // the output value returned by the main function is also a main_args with a special name (public_output)
                     if let Some(typ) = &function.sig.return_type {
                         if is_main {
-                            if !matches!(typ.kind, TyKind::Field) {
-                                unimplemented!();
+                            match typ.kind {
+                                TyKind::Field => {
+                                    typed_fn_env.store_type(
+                                        "public_output".to_string(),
+                                        TypeInfo::new_mut(typ.kind.clone(), typ.span),
+                                    )?;
+                                }
+                                TyKind::Array(_, _) => {
+                                    typed_fn_env.store_type(
+                                        "public_output".to_string(),
+                                        TypeInfo::new_mut(typ.kind.clone(), typ.span),
+                                    )?;
+                                }
+                                _ => unimplemented!(),
                             }
-
-                            typed_fn_env.store_type(
-                                "public_output".to_string(),
-                                TypeInfo::new_mut(typ.kind.clone(), typ.span),
-                            )?;
                         }
                     }