feat: add Expr::as_any_integer and Expr::as_member_access (#5742)

# Description

## Problem

Part of #5668

## Summary

## Additional Context

## Documentation

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [x] **[For Experimental Features]** Documentation to be submitted in a
separate PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

compiler/noirc_frontend/src/hir/comptime/interpreter/builtin.rs

@@ -52,6 +52,8 @@ impl<'local, 'context> Interpreter<'local, 'context> {
             "expr_as_function_call" => expr_as_function_call(arguments, return_type, location),
             "expr_as_if" => expr_as_if(arguments, return_type, location),
             "expr_as_index" => expr_as_index(arguments, return_type, location),
+            "expr_as_integer" => expr_as_integer(arguments, return_type, location),
+            "expr_as_member_access" => expr_as_member_access(arguments, return_type, location),
             "expr_as_unary_op" => expr_as_unary_op(arguments, return_type, location),
             "expr_as_tuple" => expr_as_tuple(arguments, return_type, location),
             "is_unconstrained" => Ok(Value::Bool(true)),
@@ -839,6 +841,37 @@ fn expr_as_index(
     })
 }
 
+// fn as_integer(self) -> Option<(Field, bool)>
+fn expr_as_integer(
+    arguments: Vec<(Value, Location)>,
+    return_type: Type,
+    location: Location,
+) -> IResult<Value> {
+    expr_as(arguments, return_type.clone(), location, |expr| {
+        if let ExpressionKind::Literal(Literal::Integer(field, sign)) = expr {
+            Some(Value::Tuple(vec![Value::Field(field), Value::Bool(sign)]))
+        } else {
+            None
+        }
+    })
+}
+
+// fn as_member_access(self) -> Option<(Expr, Quoted)>
+fn expr_as_member_access(
+    arguments: Vec<(Value, Location)>,
+    return_type: Type,
+    location: Location,
+) -> IResult<Value> {
+    expr_as(arguments, return_type, location, |expr| {
+        if let ExpressionKind::MemberAccess(member_access) = expr {
+            let tokens = Rc::new(vec![Token::Ident(member_access.rhs.0.contents.clone())]);
+            Some(Value::Tuple(vec![Value::Expr(member_access.lhs.kind), Value::Quoted(tokens)]))
+        } else {
+            None
+        }
+    })
+}
+
 // fn as_unary_op(self) -> Option<(UnaryOp, Expr)>
 fn expr_as_unary_op(
     arguments: Vec<(Value, Location)>,

noir_stdlib/src/meta/expr.nr

@@ -3,6 +3,9 @@ use crate::meta::op::UnaryOp;
 use crate::meta::op::BinaryOp;
 
 impl Expr {
+    #[builtin(expr_as_integer)]
+    fn as_integer(self) -> Option<(Field, bool)> {}
+
     #[builtin(expr_as_binary_op)]
     fn as_binary_op(self) -> Option<(Expr, BinaryOp, Expr)> {}
 
@@ -18,6 +21,9 @@ impl Expr {
     #[builtin(expr_as_index)]
     fn as_index(self) -> Option<(Expr, Expr)> {}
 
+    #[builtin(expr_as_member_access)]
+    fn as_member_access(self) -> Option<(Expr, Quoted)> {}
+
     #[builtin(expr_as_tuple)]
     fn as_tuple(self) -> Option<[Expr]> {}
 

test_programs/compile_success_empty/comptime_exp/src/main.nr

@@ -59,6 +59,18 @@ fn main() {
         assert(get_binary_op(quote { x >> y }).is_shift_right());
         assert(get_binary_op(quote { x << y }).is_shift_left());
         assert(get_binary_op(quote { x % y }).is_modulo());
+
+        // Check Expr::as_integer
+        let expr = quote { 1 }.as_expr().unwrap();
+        assert_eq((1, false), expr.as_integer().unwrap());
+
+        let expr = quote { -2 }.as_expr().unwrap();
+        assert_eq((2, true), expr.as_integer().unwrap());
+
+        // Check Expr::as_member_access
+        let expr = quote { foo.bar }.as_expr().unwrap();
+        let (_, name) = expr.as_member_access().unwrap();
+        assert_eq(name, quote { bar });
     }
 }