From 93347d8e7b15c5caff993b2885d4a3b62c6b36b1 Mon Sep 17 00:00:00 2001
From: KtorZ <matthias.benkort@gmail.com>
Date: Fri, 1 Mar 2024 17:02:49 +0100
Subject: [PATCH] Add Fuzzer to the prelude.

---
 crates/aiken-lang/src/builtins.rs             | 26 ++++++++++++++++++-
 .../acceptance_tests/095/lib/aiken/fuzz.ak    |  3 ---
 examples/acceptance_tests/095/lib/foo.ak      |  2 +-
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/crates/aiken-lang/src/builtins.rs b/crates/aiken-lang/src/builtins.rs
index 90c6b947..4417a89b 100644
--- a/crates/aiken-lang/src/builtins.rs
+++ b/crates/aiken-lang/src/builtins.rs
@@ -29,7 +29,7 @@ pub const OPTION: &str = "Option";
 pub const ORDERING: &str = "Ordering";
 pub const REDEEMER_WRAPPER: &str = "RedeemerWrapper";
 pub const PRNG: &str = "PRNG";
-pub const FUZZER: &str = "FUZZER";
+pub const FUZZER: &str = "Fuzzer";
 
 /// Build a prelude that can be injected
 /// into a compiler pipeline
@@ -482,6 +482,23 @@ pub fn prelude(id_gen: &IdGenerator) -> TypeInfo {
         ),
     );
 
+    // Fuzzer
+    //
+    // pub type Fuzzer<a> =
+    //   fn(PRNG) -> Option<(PRNG, a)>
+
+    let fuzzer_value = generic_var(id_gen.next());
+    prelude.types.insert(
+        FUZZER.to_string(),
+        TypeConstructor {
+            location: Span::empty(),
+            parameters: vec![fuzzer_value.clone()],
+            tipo: fuzzer(fuzzer_value),
+            module: "".to_string(),
+            public: true,
+        },
+    );
+
     prelude
 }
 
@@ -1302,6 +1319,13 @@ pub fn prng() -> Rc<Type> {
     })
 }
 
+pub fn fuzzer(a: Rc<Type>) -> Rc<Type> {
+    Rc::new(Type::Fn {
+        args: vec![prng()],
+        ret: option(tuple(vec![prng(), a])),
+    })
+}
+
 pub fn list(t: Rc<Type>) -> Rc<Type> {
     Rc::new(Type::App {
         public: true,
diff --git a/examples/acceptance_tests/095/lib/aiken/fuzz.ak b/examples/acceptance_tests/095/lib/aiken/fuzz.ak
index 4c783742..2c9589a9 100644
--- a/examples/acceptance_tests/095/lib/aiken/fuzz.ak
+++ b/examples/acceptance_tests/095/lib/aiken/fuzz.ak
@@ -2,9 +2,6 @@ use aiken/builtin
 
 const max_int: Int = 255
 
-pub type Fuzzer<a> =
-  fn(PRNG) -> Option<(PRNG, a)>
-
 // Primitives
 
 pub fn any_int() -> Fuzzer<Int> {
diff --git a/examples/acceptance_tests/095/lib/foo.ak b/examples/acceptance_tests/095/lib/foo.ak
index b73ea8d8..680d633d 100644
--- a/examples/acceptance_tests/095/lib/foo.ak
+++ b/examples/acceptance_tests/095/lib/foo.ak
@@ -1,5 +1,5 @@
 use aiken/dict.{Dict}
-use aiken/fuzz.{Fuzzer}
+use aiken/fuzz
 use aiken/int
 
 pub type Season {