feat(stdlib): Vec type (#1905)

* add multiple slice builtin funcs

* initial new stdlib Vec method that uses slices

* a couple more methods and starting to test

* remove Vec keyword from lexer and finish Vec test

* enable array index panic in acir gen when enable_side_effects_var is None

* Update crates/nargo_cli/tests/test_data_ssa_refactor/vectors/src/main.nr

* Update crates/nargo_cli/tests/test_data_ssa_refactor/slices/src/main.nr

* when slices are not enabled do not include collections module in stdlib

* fix in collect_defs

* remove append builtin for now

* Update noir_stdlib/src/collections/vec.nr

Co-authored-by: jfecher <jake@aztecprotocol.com>

* Update noir_stdlib/src/collections/vec.nr

Co-authored-by: jfecher <jake@aztecprotocol.com>

* revert check on option and merge in pr #1906

* use from_slice in test

* switch retain for collections and slice modules to &&

---------

Co-authored-by: jfecher <jake@aztecprotocol.com>

crates/nargo_cli/tests/test_data_ssa_refactor/slices/src/main.nr

@@ -5,7 +5,6 @@ fn main(x : Field, y : pub Field) {
     /// is not yet supported
 
     let mut slice: [Field] = [0; 2];
-
     assert(slice[0] == 0);
     assert(slice[0] != 1);
     slice[0] = x;

crates/nargo_cli/tests/test_data_ssa_refactor/vectors/Nargo.toml

@@ -0,0 +1,5 @@
+[package]
+authors = [""]
+compiler_version = "0.7.1"
+
+[dependencies]

crates/nargo_cli/tests/test_data_ssa_refactor/vectors/Prover.toml

@@ -0,0 +1,2 @@
+x = "5"
+y = "10"

crates/nargo_cli/tests/test_data_ssa_refactor/vectors/src/main.nr

@@ -0,0 +1,32 @@
+use dep::std::collections::vec::Vec;
+
+fn main(x: Field, y: pub Field) {
+    let mut vector = Vec::new();
+
+    assert(vector.len() == 0);
+    for i in 0..5 {
+        vector.push(i);
+    }
+    assert(vector.len() == 5);
+    for i in 0..5 {
+        assert(i == vector.get(i));
+    }
+
+    let last_elem = vector.pop();
+    assert(last_elem == 4);
+    assert(vector.len() == 4);
+
+    vector.insert(2, 100);
+    assert(vector.get(2) == 100);
+    assert(vector.get(4) == 3);
+    assert(vector.len() == 5);
+
+    let removed_elem = vector.remove(3);
+    assert(removed_elem == 2);
+    assert(vector.get(3) == 3);
+    assert(vector.len() == 4);
+
+    let mut inputs_vector = Vec::from_slice([x, y]);
+    assert(inputs_vector.get(0) == x);
+    assert(inputs_vector.get(1) == y);
+}

crates/noirc_evaluator/src/ssa_refactor/ir/instruction.rs

@@ -300,7 +300,6 @@ impl Instruction {
                 if let (Some((array, _)), Some(index)) = (array, index) {
                     let index =
                         index.try_to_u64().expect("Expected array index to fit in u64") as usize;
-
                     if index < array.len() {
                         return SimplifiedTo(array[index]);
                     }

crates/noirc_frontend/src/hir/def_map/mod.rs

@@ -93,7 +93,8 @@ impl CrateDefMap {
                 .to_str()
                 .expect("expected std path to be convertible to str");
             assert_eq!(path_as_str, "std/lib");
-            ast.module_decls.retain(|ident| ident.0.contents != "slice");
+            ast.module_decls
+                .retain(|ident| ident.0.contents != "slice" && ident.0.contents != "collections");
         }
 
         // Allocate a default Module for the root, giving it a ModuleId

crates/noirc_frontend/src/lexer/token.rs

@@ -442,7 +442,6 @@ pub enum Keyword {
     Struct,
     Unconstrained,
     Use,
-    Vec,
     While,
 }
 
@@ -478,7 +477,6 @@ impl fmt::Display for Keyword {
             Keyword::Struct => write!(f, "struct"),
             Keyword::Unconstrained => write!(f, "unconstrained"),
             Keyword::Use => write!(f, "use"),
-            Keyword::Vec => write!(f, "Vec"),
             Keyword::While => write!(f, "while"),
         }
     }
@@ -517,7 +515,6 @@ impl Keyword {
             "struct" => Keyword::Struct,
             "unconstrained" => Keyword::Unconstrained,
             "use" => Keyword::Use,
-            "Vec" => Keyword::Vec,
             "while" => Keyword::While,
 
             "true" => return Some(Token::Bool(true)),

noir_stdlib/src/collections/vec.nr

@@ -0,0 +1,60 @@
+struct Vec<T> { 
+    slice: [T]
+}
+
+// A mutable vector type implemented as a wrapper around immutable slices.
+// A separate type is technically not needed but helps differentiate which operations are mutable.
+impl<T> Vec<T> {
+    fn new() -> Self {
+        Self { slice: [] }
+    }
+
+    // Create a Vec containing each element from the given slice.
+    // Mutations to the resulting Vec will not affect the original slice.
+    fn from_slice(slice: [T]) -> Self {
+        Self { slice }
+    }
+
+    /// Get an element from the vector at the given index.
+    /// Panics if the given index
+    /// points beyond the end of the vector.
+    fn get(&mut self, index: Field) -> T {
+        self.slice[index]
+     }
+
+    /// Push a new element to the end of the vector, returning a
+    /// new vector with a length one greater than the
+    /// original unmodified vector.
+    fn push(&mut self, elem: T) { 
+        self.slice = self.slice.push_back(elem);
+    }
+
+    /// Pop an element from the end of the given vector, returning
+    /// a new vector with a length of one less than the given vector,
+    /// as well as the popped element.
+    /// Panics if the given vector's length is zero.
+    fn pop(&mut self) -> T { 
+        let (popped_slice, last_elem) = self.slice.pop_back();
+        self.slice = popped_slice;
+        last_elem
+    }
+
+    /// Insert an element at a specified index, shifting all elements 
+    /// after it to the right
+    fn insert(&mut self, index: Field, elem: T) {
+        self.slice = self.slice.insert(index, elem);
+    } 
+
+    /// Remove an element at a specified index, shifting all elements
+    /// after it to the left, returning the removed element
+    fn remove(&mut self, index: Field) -> T {
+        let (new_slice, elem) = self.slice.remove(index);
+        self.slice = new_slice;
+        elem
+    }
+
+    /// Returns the number of elements in the vector
+    fn len(self: Self) -> Field {
+        self.slice.len()
+    }
+}

noir_stdlib/src/lib.nr

@@ -12,6 +12,7 @@ mod sha512;
 mod field;
 mod ec;
 mod unsafe;
+mod collections;
 mod compat;
 
 #[builtin(println)]