Fix the test

When Grackle compiles a KCL array into KCEP memory, it will write the array length as the first element in memory.

src/wasm-lib/grackle/src/binding_scope.rs

@@ -17,7 +17,12 @@ pub enum EpBinding {
     /// A KCL value which gets stored in a particular address in KCEP memory.
     Single(Address),
     /// A sequence of KCL values, indexed by their position in the sequence.
-    Sequence(Vec<EpBinding>),
+    Sequence {
+        /// Address where the length of the array is stored.
+        length_at: Address,
+        /// Where is each element in the array bound?
+        elements: Vec<EpBinding>,
+    },
     /// A sequence of KCL values, indexed by their identifier.
     Map(HashMap<String, EpBinding>),
     /// Not associated with a KCEP address.
@@ -38,9 +43,11 @@ impl EpBinding {
             LiteralIdentifier::Literal(litval) => match litval.value {
                 // Arrays can be indexed by integers.
                 LiteralValue::IInteger(i) => match self {
-                    EpBinding::Sequence(seq) => {
+                    EpBinding::Sequence { length_at: _, elements } => {
                         let i = usize::try_from(i).map_err(|_| CompileError::InvalidIndex(i.to_string()))?;
-                        seq.get(i).ok_or(CompileError::IndexOutOfBounds { i, len: seq.len() })
+                        elements
+                            .get(i)
+                            .ok_or(CompileError::IndexOutOfBounds { i, len: elements.len() })
                     }
                     EpBinding::Map(_) => Err(CompileError::CannotIndex),
                     EpBinding::Single(_) => Err(CompileError::CannotIndex),
@@ -50,7 +57,7 @@ impl EpBinding {
                 LiteralValue::String(property) => match self {
                     EpBinding::Single(_) => Err(CompileError::NoProperties),
                     EpBinding::Function(_) => Err(CompileError::NoProperties),
-                    EpBinding::Sequence(_) => Err(CompileError::ArrayDoesNotHaveProperties),
+                    EpBinding::Sequence { .. } => Err(CompileError::ArrayDoesNotHaveProperties),
                     EpBinding::Map(map) => map.get(&property).ok_or(CompileError::UndefinedProperty { property }),
                 },
                 // It's never valid to index by a fractional number.

src/wasm-lib/grackle/src/lib.rs

@@ -231,7 +231,7 @@ impl Planner {
                             binding: arg,
                         } = match KclValueGroup::from(argument) {
                             KclValueGroup::Single(value) => self.plan_to_compute_single(ctx, value)?,
-                            KclValueGroup::ArrayExpression(_) => todo!(),
+                            KclValueGroup::ArrayExpression(expr) => self.plan_to_bind_array(ctx, *expr)?,
                             KclValueGroup::ObjectExpression(_) => todo!(),
                         };
                         acc_instrs.extend(new_instructions);
@@ -411,9 +411,9 @@ impl Planner {
             .declarations
             .into_iter()
             .try_fold(Vec::new(), |mut acc, declaration| {
-                let (instrs, binding) = self.plan_to_bind_one(&mut ctx, declaration.init)?;
+                let EvalPlan { instructions, binding } = self.plan_to_bind_one(&mut ctx, declaration.init)?;
                 self.binding_scope.bind(declaration.id.name, binding);
-                acc.extend(instrs);
+                acc.extend(instructions);
                 Ok(acc)
             })
     }
@@ -422,69 +422,14 @@ impl Planner {
         &mut self,
         ctx: &mut Context,
         value_being_bound: ast::types::Value,
-    ) -> Result<(Vec<Instruction>, EpBinding), CompileError> {
+    ) -> Result<EvalPlan, CompileError> {
         match KclValueGroup::from(value_being_bound) {
             KclValueGroup::Single(init_value) => {
                 // Simple! Just evaluate it, note where the final value will be stored in KCEP memory,
                 // and bind it to the KCL identifier.
-                let EvalPlan { instructions, binding } = self.plan_to_compute_single(ctx, init_value)?;
-                Ok((instructions, binding))
-            }
-            KclValueGroup::ArrayExpression(expr) => {
-                // First, emit a plan to compute each element of the array.
-                // Collect all the bindings from each element too.
-                let (instructions, bindings) = expr.elements.into_iter().try_fold(
-                    (Vec::new(), Vec::new()),
-                    |(mut acc_instrs, mut acc_bindings), element| {
-                        match KclValueGroup::from(element) {
-                            KclValueGroup::Single(value) => {
-                                // If this element of the array is a single value, then binding it is
-                                // straightforward -- you got a single binding, no need to change anything.
-                                let EvalPlan { instructions, binding } = self.plan_to_compute_single(ctx, value)?;
-                                acc_instrs.extend(instructions);
-                                acc_bindings.push(binding);
-                            }
-                            KclValueGroup::ArrayExpression(expr) => {
-                                // If this element of the array is _itself_ an array, then we need to
-                                // emit a plan to calculate each element of this child array.
-                                // Then we collect the child array's bindings, and bind them to one
-                                // element of the parent array.
-                                let binding = expr
-                                    .elements
-                                    .into_iter()
-                                    .try_fold(Vec::new(), |mut seq, child_element| {
-                                        let (instructions, binding) = self.plan_to_bind_one(ctx, child_element)?;
-                                        acc_instrs.extend(instructions);
-                                        seq.push(binding);
-                                        Ok(seq)
-                                    })
-                                    .map(EpBinding::Sequence)?;
-                                acc_bindings.push(binding);
-                            }
-                            KclValueGroup::ObjectExpression(expr) => {
-                                // If this element of the array is an object, then we need to
-                                // emit a plan to calculate each value of each property of the object.
-                                // Then we collect the bindings for each child value, and bind them to one
-                                // element of the parent array.
-                                let map = HashMap::with_capacity(expr.properties.len());
-                                let binding = expr
-                                    .properties
-                                    .into_iter()
-                                    .try_fold(map, |mut map, property| {
-                                        let (instructions, binding) = self.plan_to_bind_one(ctx, property.value)?;
-                                        map.insert(property.key.name, binding);
-                                        acc_instrs.extend(instructions);
-                                        Ok(map)
-                                    })
-                                    .map(EpBinding::Map)?;
-                                acc_bindings.push(binding);
-                            }
-                        };
-                        Ok((acc_instrs, acc_bindings))
-                    },
-                )?;
-                Ok((instructions, EpBinding::Sequence(bindings)))
+                self.plan_to_compute_single(ctx, init_value)
             }
+            KclValueGroup::ArrayExpression(expr) => self.plan_to_bind_array(ctx, *expr),
             KclValueGroup::ObjectExpression(expr) => {
                 // Convert the object to a sequence of key-value pairs.
                 let mut kvs = expr.properties.into_iter().map(|prop| (prop.key, prop.value));
@@ -502,16 +447,22 @@ impl Planner {
                                 // each element of that array. Collect their bindings, and bind them all
                                 // under one property of the parent object.
                                 let n = expr.elements.len();
+                                let length_at = self.next_addr.offset_by(1);
+                                acc_instrs.push(Instruction::SetPrimitive {
+                                    address: length_at,
+                                    value: n.into(),
+                                });
                                 let binding = expr
                                     .elements
                                     .into_iter()
                                     .try_fold(Vec::with_capacity(n), |mut seq, child_element| {
-                                        let (instructions, binding) = self.plan_to_bind_one(ctx, child_element)?;
+                                        let EvalPlan { instructions, binding } =
+                                            self.plan_to_bind_one(ctx, child_element)?;
                                         seq.push(binding);
                                         acc_instrs.extend(instructions);
                                         Ok(seq)
                                     })
-                                    .map(EpBinding::Sequence)?;
+                                    .map(|elements| EpBinding::Sequence { length_at, elements })?;
                                 acc_bindings.insert(key.name, binding);
                             }
                             KclValueGroup::ObjectExpression(expr) => {
@@ -524,7 +475,8 @@ impl Planner {
                                     .properties
                                     .into_iter()
                                     .try_fold(HashMap::with_capacity(n), |mut map, property| {
-                                        let (instructions, binding) = self.plan_to_bind_one(ctx, property.value)?;
+                                        let EvalPlan { instructions, binding } =
+                                            self.plan_to_bind_one(ctx, property.value)?;
                                         map.insert(property.key.name, binding);
                                         acc_instrs.extend(instructions);
                                         Ok(map)
@@ -536,10 +488,90 @@ impl Planner {
                         Ok((acc_instrs, acc_bindings))
                     },
                 )?;
-                Ok((instructions, EpBinding::Map(each_property_binding)))
+                Ok(EvalPlan {
+                    instructions,
+                    binding: EpBinding::Map(each_property_binding),
+                })
             }
         }
     }
+
+    fn plan_to_bind_array(
+        &mut self,
+        ctx: &mut Context,
+        expr: ast::types::ArrayExpression,
+    ) -> Result<EvalPlan, CompileError> {
+        let length_at = self.next_addr.offset_by(1);
+        let mut instructions = vec![Instruction::SetPrimitive {
+            address: length_at,
+            value: expr.elements.len().into(),
+        }];
+        // First, emit a plan to compute each element of the array.
+        // Collect all the bindings from each element too.
+        let (instrs, bindings) = expr.elements.into_iter().try_fold(
+            (Vec::new(), Vec::new()),
+            |(mut acc_instrs, mut acc_bindings), element| {
+                match KclValueGroup::from(element) {
+                    KclValueGroup::Single(value) => {
+                        // If this element of the array is a single value, then binding it is
+                        // straightforward -- you got a single binding, no need to change anything.
+                        let EvalPlan { instructions, binding } = self.plan_to_compute_single(ctx, value)?;
+                        acc_instrs.extend(instructions);
+                        acc_bindings.push(binding);
+                    }
+                    KclValueGroup::ArrayExpression(expr) => {
+                        // If this element of the array is _itself_ an array, then we need to
+                        // emit a plan to calculate each element of this child array.
+                        // Then we collect the child array's bindings, and bind them to one
+                        // element of the parent array.
+                        let length_at = self.next_addr.offset_by(1);
+                        acc_instrs.push(Instruction::SetPrimitive {
+                            address: length_at,
+                            value: expr.elements.len().into(),
+                        });
+                        let binding = expr
+                            .elements
+                            .into_iter()
+                            .try_fold(Vec::new(), |mut seq, child_element| {
+                                let EvalPlan { instructions, binding } = self.plan_to_bind_one(ctx, child_element)?;
+                                acc_instrs.extend(instructions);
+                                seq.push(binding);
+                                Ok(seq)
+                            })
+                            .map(|elements| EpBinding::Sequence { length_at, elements })?;
+                        acc_bindings.push(binding);
+                    }
+                    KclValueGroup::ObjectExpression(expr) => {
+                        // If this element of the array is an object, then we need to
+                        // emit a plan to calculate each value of each property of the object.
+                        // Then we collect the bindings for each child value, and bind them to one
+                        // element of the parent array.
+                        let map = HashMap::with_capacity(expr.properties.len());
+                        let binding = expr
+                            .properties
+                            .into_iter()
+                            .try_fold(map, |mut map, property| {
+                                let EvalPlan { instructions, binding } = self.plan_to_bind_one(ctx, property.value)?;
+                                map.insert(property.key.name, binding);
+                                acc_instrs.extend(instructions);
+                                Ok(map)
+                            })
+                            .map(EpBinding::Map)?;
+                        acc_bindings.push(binding);
+                    }
+                };
+                Ok((acc_instrs, acc_bindings))
+            },
+        )?;
+        instructions.extend(instrs);
+        Ok(EvalPlan {
+            instructions,
+            binding: EpBinding::Sequence {
+                length_at,
+                elements: bindings,
+            },
+        })
+    }
 }
 
 /// Every KCL literal value is equivalent to an Execution Plan value, and therefore can be

src/wasm-lib/grackle/src/tests.rs

@@ -48,16 +48,22 @@ fn bind_array() {
     assert_eq!(
         plan,
         vec![
+            // Arrays start with the length.
             Instruction::SetPrimitive {
                 address: Address::ZERO,
+                value: 3usize.into(),
+            },
+            // Then the elements follow.
+            Instruction::SetPrimitive {
+                address: Address::ZERO + 1,
                 value: 44i64.into(),
             },
             Instruction::SetPrimitive {
-                address: Address::ZERO.offset(1),
+                address: Address::ZERO + 2,
                 value: 55i64.into(),
             },
             Instruction::SetPrimitive {
-                address: Address::ZERO.offset(2),
+                address: Address::ZERO + 3,
                 value: "sixty-six".to_owned().into(),
             }
         ]
@@ -73,14 +79,22 @@ fn bind_nested_array() {
         vec![
             Instruction::SetPrimitive {
                 address: Address::ZERO,
+                value: 2usize.into(),
+            },
+            Instruction::SetPrimitive {
+                address: Address::ZERO + 1,
                 value: 44i64.into(),
             },
             Instruction::SetPrimitive {
-                address: Address::ZERO.offset(1),
+                address: Address::ZERO + 2,
+                value: 2usize.into(),
+            },
+            Instruction::SetPrimitive {
+                address: Address::ZERO + 3,
                 value: 55i64.into(),
             },
             Instruction::SetPrimitive {
-                address: Address::ZERO.offset(2),
+                address: Address::ZERO + 4,
                 value: "sixty-six".to_owned().into(),
             }
         ]
@@ -96,14 +110,18 @@ fn bind_arrays_with_objects_elements() {
         vec![
             Instruction::SetPrimitive {
                 address: Address::ZERO,
+                value: 2usize.into()
+            },
+            Instruction::SetPrimitive {
+                address: Address::ZERO + 1,
                 value: 44i64.into(),
             },
             Instruction::SetPrimitive {
-                address: Address::ZERO.offset(1),
+                address: Address::ZERO + 2,
                 value: 55i64.into(),
             },
             Instruction::SetPrimitive {
-                address: Address::ZERO.offset(2),
+                address: Address::ZERO + 3,
                 value: "sixty-six".to_owned().into(),
             }
         ]
@@ -187,6 +205,45 @@ fn use_native_function_add() {
     );
 }
 
+#[test]
+fn arrays_as_parameters() {
+    let program = "fn identity = (x) => { return x }
+    let array = identity([1,2,3])";
+    let (plan, scope) = must_plan(program);
+    let expected_plan = vec![
+        // Array length
+        Instruction::SetPrimitive {
+            address: Address::ZERO,
+            value: 3usize.into(),
+        },
+        // Array contents
+        Instruction::SetPrimitive {
+            address: Address::ZERO + 1,
+            value: 1i64.into(),
+        },
+        Instruction::SetPrimitive {
+            address: Address::ZERO + 2,
+            value: 2i64.into(),
+        },
+        Instruction::SetPrimitive {
+            address: Address::ZERO + 3,
+            value: 3i64.into(),
+        },
+    ];
+    assert_eq!(plan, expected_plan);
+    assert_eq!(
+        scope.get("array").unwrap(),
+        &EpBinding::Sequence {
+            length_at: Address::ZERO,
+            elements: vec![
+                EpBinding::Single(Address::ZERO + 1),
+                EpBinding::Single(Address::ZERO + 2),
+                EpBinding::Single(Address::ZERO + 3),
+            ]
+        }
+    )
+}
+
 #[test]
 fn use_native_function_id() {
     let program = "let x = id(2)";
@@ -265,7 +322,7 @@ fn member_expressions_array() {
     let (_plan, scope) = must_plan(program);
     match scope.get("first").unwrap() {
         EpBinding::Single(addr) => {
-            assert_eq!(*addr, Address::ZERO);
+            assert_eq!(*addr, Address::ZERO + 2);
         }
         other => {
             panic!("expected 'number' bound to 0x0 but it was bound to {other:?}");
@@ -273,7 +330,7 @@ fn member_expressions_array() {
     }
     match scope.get("last").unwrap() {
         EpBinding::Single(addr) => {
-            assert_eq!(*addr, Address::ZERO + 3);
+            assert_eq!(*addr, Address::ZERO + 6);
         }
         other => {
             panic!("expected 'number' bound to 0x3 but it was bound to {other:?}");
@@ -682,14 +739,11 @@ fn store_object() {
     assert_eq!(
         bindings.get("x0").unwrap(),
         &EpBinding::Map(HashMap::from([
-            ("a".to_owned(), EpBinding::Single(Address::ZERO),),
-            ("b".to_owned(), EpBinding::Single(Address::ZERO.offset(1))),
+            ("a".to_owned(), EpBinding::Single(Address::ZERO)),
+            ("b".to_owned(), EpBinding::Single(Address::ZERO + 1)),
             (
                 "c".to_owned(),
-                EpBinding::Map(HashMap::from([(
-                    "d".to_owned(),
-                    EpBinding::Single(Address::ZERO.offset(2))
-                )]))
+                EpBinding::Map(HashMap::from([("d".to_owned(), EpBinding::Single(Address::ZERO + 2))]))
             ),
         ]))
     )
@@ -697,7 +751,7 @@ fn store_object() {
 
 #[test]
 fn store_object_with_array_property() {
-    let program = "const x0 = {a: 1, b: [2, 3]}";
+    let program = "const x0 = {a: 1, b: [22, 33]}";
     let (actual, bindings) = must_plan(program);
     let expected = vec![
         Instruction::SetPrimitive {
@@ -705,12 +759,16 @@ fn store_object_with_array_property() {
             value: 1i64.into(),
         },
         Instruction::SetPrimitive {
-            address: Address::ZERO.offset(1),
-            value: 2i64.into(),
+            address: Address::ZERO + 1,
+            value: 2usize.into(),
         },
         Instruction::SetPrimitive {
-            address: Address::ZERO.offset(2),
-            value: 3i64.into(),
+            address: Address::ZERO + 2,
+            value: 22i64.into(),
+        },
+        Instruction::SetPrimitive {
+            address: Address::ZERO + 3,
+            value: 33i64.into(),
         },
     ];
     assert_eq!(actual, expected);
@@ -721,10 +779,13 @@ fn store_object_with_array_property() {
             ("a".to_owned(), EpBinding::Single(Address::ZERO),),
             (
                 "b".to_owned(),
-                EpBinding::Sequence(vec![
-                    EpBinding::Single(Address::ZERO.offset(1)),
-                    EpBinding::Single(Address::ZERO.offset(2)),
-                ])
+                EpBinding::Sequence {
+                    length_at: Address::ZERO.offset(1),
+                    elements: vec![
+                        EpBinding::Single(Address::ZERO.offset(2)),
+                        EpBinding::Single(Address::ZERO.offset(3)),
+                    ]
+                }
             ),
         ]))
     )