update examples

examples/bubblesort/src/main.leo

@@ -16,6 +16,7 @@
 // Note that the implementation below uses tuples instead of arrays.
 // The implementation also manually unrolls the loop.
 
+@program
 function bubble_sort(
                      arr0: u32,
                      arr1: u32, 

examples/core/src/main.leo

@@ -2,6 +2,7 @@
 // Core circuit functions are built-in to the Leo language and call handwritten, optimized circuits in the AVM.
 // To call a core circuit function, use the correct capitalized circuit identifier followed by two colons
 // and then the function. Example: `Pedersen64::hash()`.
+@program
 function main(a: field) -> field {
     let b: field = BHP256::hash(a);
     let c: field = Poseidon2::hash(b);

examples/groups/src/main.leo

@@ -1,5 +1,7 @@
 // This function takes a group coordinate as input `a` and performs several operations which should output the `0group`.
 // Note that the operations can be called as associated functions on the `a` variable.
+
+@program
 function main(a: group) -> group {
     // unary
     let e: group = a.double(); // 2a

examples/helloworld/src/main.leo

@@ -1,7 +1,7 @@
 import foo.leo;
 
 // The 'helloworld' main function.
-
+@program
 function main(public a: u32, b: u32) -> u32 {
     return a + b;
 }

examples/import_point/src/main.leo

@@ -3,6 +3,7 @@
 import point.leo;
 
 // The main function.
+@program
 function main(public a: u32, b: u32) -> u32 {
     return a + b;
 }

examples/message/src/main.leo

@@ -11,6 +11,7 @@ circuit Message {
 
 // The "main" function of this Leo program takes a "Message" circuit type as input.
 // To see how to input variable "m" is passed in open up `inputs/message.in`.
+@program
 function main(m: Message) -> field {
 
     // 1. Define the "Message" type.

examples/token/src/main.leo

@@ -1,3 +1,6 @@
+// This example demonstrates an example of a minting and transferring a token in Leo.
+
+// The `Token` record datatype.
 record Token {
     // The token owner.
     owner: address,
@@ -9,6 +12,7 @@ record Token {
 
 // The `mint` function initializes a new record with the
 // to the receiver of tokens in `r1` for the receiver in `r0`.
+@program
 function mint(owner: address, amount: u64) -> Token {
     return Token {
         owner: owner,
@@ -19,6 +23,7 @@ function mint(owner: address, amount: u64) -> Token {
 
 // The `transfer` function sends the specified number of tokens
 // to the receiver from the provided token record.
+@program
 function transfer(token: Token, to: address, amount: u64) -> (Token, Token) {
 
     // Checks the given token record has sufficient balance.