feat: anonymous generic impl parameters (#469)

Author: julio4

book.toml

@@ -6,7 +6,7 @@ src = "src"
 title = "The Cairo Programming Language"
 
 [build]
-extra-watch-dirs = ["po"]
+extra-watch-dirs = ["po", "listings"]
 
 [preprocessor.cairo]
 after = ["links"]

listings/ch03-common-collections/no_listing_10_custom_methods/src/lib.cairo

@@ -5,7 +5,7 @@ use dict::Felt252DictEntryTrait;
 use debug::PrintTrait;
 
 // ANCHOR: custom_get
-fn custom_get<T, impl TDefault: Felt252DictValue<T>, impl TDrop: Drop<T>, impl TCopy: Copy<T>>(
+fn custom_get<T, +Felt252DictValue<T>, +Drop<T>, +Copy<T>>(
     ref dict: Felt252Dict<T>, key: felt252
 ) -> T {
     // Get the new entry and the previous value held at `key`
@@ -23,13 +23,7 @@ fn custom_get<T, impl TDefault: Felt252DictValue<T>, impl TDrop: Drop<T>, impl T
 // ANCHOR_END: custom_get
 
 // ANCHOR: custom_insert
-fn custom_insert<
-    T,
-    impl TDefault: Felt252DictValue<T>,
-    impl TDestruct: Destruct<T>,
-    impl TPrint: PrintTrait<T>,
-    impl TDrop: Drop<T>
->(
+fn custom_insert<T, +Felt252DictValue<T>, +Destruct<T>, +PrintTrait<T>, +Drop<T>>(
     ref dict: Felt252Dict<T>, key: felt252, value: T
 ) {
     // Get the last entry associated with `key`

listings/ch03-common-collections/no_listing_12_dict_struct_member/src/lib.cairo

@@ -8,35 +8,33 @@ struct UserDatabase<T> {
 // ANCHOR: trait
 trait UserDatabaseTrait<T> {
     fn new() -> UserDatabase<T>;
-    fn add_user<impl TDrop: Drop<T>>(ref self: UserDatabase<T>, name: felt252, balance: T);
-    fn get_balance<impl TCopy: Copy<T>>(ref self: UserDatabase<T>, name: felt252) -> T;
+    fn add_user<+Drop<T>>(ref self: UserDatabase<T>, name: felt252, balance: T);
+    fn get_balance<+Copy<T>>(ref self: UserDatabase<T>, name: felt252) -> T;
 }
 // ANCHOR_END: trait
 
 // ANCHOR: impl
-impl UserDatabaseImpl<T, impl TDefault: Felt252DictValue<T>> of UserDatabaseTrait<T> {
+impl UserDatabaseImpl<T, +Felt252DictValue<T>> of UserDatabaseTrait<T> {
     // Creates a database
     fn new() -> UserDatabase<T> {
         UserDatabase { users_amount: 0, balances: Default::default() }
     }
 
     // Get the user's balance
-    fn get_balance<impl TCopy: Copy<T>>(ref self: UserDatabase<T>, name: felt252) -> T {
+    fn get_balance<+Copy<T>>(ref self: UserDatabase<T>, name: felt252) -> T {
         self.balances.get(name)
     }
 
     // Add a user
-    fn add_user<impl TDrop: Drop<T>>(ref self: UserDatabase<T>, name: felt252, balance: T) {
+    fn add_user<+Drop<T>>(ref self: UserDatabase<T>, name: felt252, balance: T) {
         self.balances.insert(name, balance);
         self.users_amount += 1;
     }
 }
 // ANCHOR_END: impl
 
 // ANCHOR: destruct
-impl UserDatabaseDestruct<
-    T, impl TDrop: Drop<T>, impl TDefault: Felt252DictValue<T>
-> of Destruct<UserDatabase<T>> {
+impl UserDatabaseDestruct<T, +Drop<T>, +Felt252DictValue<T>> of Destruct<UserDatabase<T>> {
     fn destruct(self: UserDatabase<T>) nopanic {
         self.balances.squash();
     }

listings/ch03-common-collections/no_listing_13_cust_struct_vect/src/lib.cairo

@@ -23,14 +23,14 @@ struct NullableVec<T> {
 }
 // ANCHOR_END: struct
 
-impl DestructNullableVec<T, impl TDrop: Drop<T>> of Destruct<NullableVec<T>> {
+impl DestructNullableVec<T, +Drop<T>> of Destruct<NullableVec<T>> {
     fn destruct(self: NullableVec<T>) nopanic {
         self.data.squash();
     }
 }
 
 // ANCHOR: implem
-impl NullableVecImpl<T, impl TDrop: Drop<T>, impl TCopy: Copy<T>> of VecTrait<NullableVec<T>, T> {
+impl NullableVecImpl<T, +Drop<T>, +Copy<T>> of VecTrait<NullableVec<T>, T> {
     fn new() -> NullableVec<T> {
         NullableVec { data: Default::default(), len: 0 }
     }

listings/ch03-common-collections/no_listing_14_cust_struct_stack/src/lib.cairo

@@ -20,17 +20,15 @@ struct NullableStack<T> {
 }
 // ANCHOR_END: struct
 
-impl DestructNullableStack<T, impl TDrop: Drop<T>> of Destruct<NullableStack<T>> {
+impl DestructNullableStack<T, +Drop<T>> of Destruct<NullableStack<T>> {
     fn destruct(self: NullableStack<T>) nopanic {
         self.data.squash();
     }
 }
 
 
 // ANCHOR: implem
-impl NullableStackImpl<
-    T, impl TDrop: Drop<T>, impl TCopy: Copy<T>
-> of StackTrait<NullableStack<T>, T> {
+impl NullableStackImpl<T, +Drop<T>, +Copy<T>> of StackTrait<NullableStack<T>, T> {
     fn push(ref self: NullableStack<T>, value: T) {
         self.data.insert(self.len.into(), nullable_from_box(BoxTrait::new(value)));
         self.len += 1;

listings/ch08-generic-types-and-traits/no_listing_02_with_tdrop/src/lib.cairo

@@ -1,4 +1,4 @@
-fn largest_list<T, impl TDrop: Drop<T>>(l1: Array<T>, l2: Array<T>) -> Array<T> {
+fn largest_list<T, +Drop<T>>(l1: Array<T>, l2: Array<T>) -> Array<T> {
     if l1.len() > l2.len() {
         l1
     } else {

listings/ch08-generic-types-and-traits/no_listing_03_missing_tcopy/src/lib.cairo

@@ -2,7 +2,7 @@
 
 // Given a list of T get the smallest one.
 // The PartialOrd trait implements comparison operations for T
-fn smallest_element<T, impl TPartialOrd: PartialOrd<T>>(list: @Array<T>) -> T {
+fn smallest_element<T, +PartialOrd<T>>(list: @Array<T>) -> T {
     // This represents the smallest element through the iteration
     // Notice that we use the desnap (*) operator
     let mut smallest = *list[0];

listings/ch08-generic-types-and-traits/no_listing_05_derive_generics/.gitignore renamed to listings/ch08-generic-types-and-traits/no_listing_05_with_anonymous_impl/.gitignore

@@ -0,0 +1,8 @@
+[package]
+name = "no_listing_05_with_anonymous_impl"
+version = "0.1.0"
+
+# See more keys and their definitions at https://docs.swmansion.com/scarb/docs/reference/manifest
+
+[dependencies]
+# foo = { path = "vendor/foo" }

listings/ch08-generic-types-and-traits/no_listing_05_with_anonymous_impl/Scarb.toml

@@ -0,0 +1,13 @@
+fn smallest_element<T, +PartialOrd<T>, +Copy<T>, +Drop<T>>(list: @Array<T>) -> T {
+    let mut smallest = *list[0];
+    let mut index = 1;
+    loop {
+        if index >= list.len() {
+            break smallest;
+        }
+        if *list[index] < smallest {
+            smallest = *list[index];
+        }
+        index = index + 1;
+    }
+}