Is your struct declared with a `let`? If so, then when you're trying to access it you are accessing the r-value itself. Try to define it like this instead: `tempvar my_struct : MyStruct = ...`


ㅤ
_This answer was originally posted on [Triality](https://triality.org/question/665)_

Hello, I am getting the following error in my starknet contract, does anyone know how to resolve it?


`Accessing struct/tuple members for r-value structs is not supported yet.`


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/665)_

Cairo error: Accessing struct/tuple members for r-value structs is not supported yet

Can I transpile any solidity version?

In SNARKs, you can use Zokrates or snarkjs to generate a proof for a program/computation and verify it, locally or on Ethereum.


Similar to [this unanswered question](https://github.com/starkware-libs/cairo-lang/issues/2), how to do the same in Cairo and STARK for, say, [the 15-puzzle](https://www.cairo-lang.org/docs/hello_cairo/puzzle.html)?


Can `cairo-run` generate a proof, or only a trace?


I can send it to [SHARP](https://www.cairo-lang.org/docs/sharp.html) with cairo-sharp, but I can't generate nor see the proof locally. Any way to generate the proof by running my own prover without SHARP?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/1138)_

How to generate a proof for a Cairo program and verify it?[StackOverflow]

protostar is great ❤️ thanks! I'm confused about the deploy command. from which account does it deploy from? also are there no gas fees on goreli when you deploy?

I want to deploy a contract from my own argent wallet I would need to declare + sign a transaction
& I guess use the StarkCurveSigner. What are your thoughts?

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

Which account does protostar deploy command from?

Hey guys,

I am having issue with generating _abi.json file when I use namespace,
Please see example below.

Does someone know solution of how to generate _abi.json file when namespace is used? I really need help 🙏 

This code generates starknet_abi.json

%lang starknet
from starkware.cairo.common.cairo_builtins import HashBuiltin
from starkware.starknet.common.syscalls import get_caller_address

@External
   func store_name{syscall_ptr: felt, pedersen_ptr: HashBuiltin, range_check_ptr}(_count: felt) -> (even : felt) {
      alloc_locals;
      local even;

      let (caller) = get_caller_address();
      if (_count == 2) {
         even = 1;
      }
      return (even=even);
   }
=============================================================
This code does not generates starknet_abi.json (please see use of  namespace)

%lang starknet
from starkware.cairo.common.cairo_builtins import HashBuiltin
from starkware.starknet.common.syscalls import get_caller_address

namespace ToMoon {
@External
   func store_name{syscall_ptr: felt, pedersen_ptr: HashBuiltin, range_check_ptr}(_count: felt) -> (even : felt) {
      alloc_locals;
      local even;

      let (caller) = get_caller_address();
      if (_count == 2) {
         even = 1;
      }
      return (even=even);
   }
}



Issue with generating _abi.json file 

Hello! This is day 12 of the 17 days of the Cairo Challenge. And I have no idea how to solve the [playground](https://www.cairo-lang.org/playground/) exercise “Structs.  Perhaps you can help me?

```
// In this challenge you're going to implement a stack using a linked list.
//
// Add the missing code so that main() runs successfully.

from starkware.cairo.common.registers import get_fp_and_pc

struct Node {
    // A pointer to the next node in the stack.
    next: Node*,

    // The value of the node.
    value: felt,

    // The number of elements in the stack.
    size: felt,
}

// Returns an empty stack.
func empty_stack() -> (stack: Node*) {
    alloc_locals;
    local new_node: Node;
    assert new_node.next = cast(0, Node*);
    assert new_node.value = 0;
    assert new_node.size = 0;

    // The usage of get_fp_and_pc() here is necessary in order
    // to access the address of a local variable (&new_node).
    // You can read more about get_fp_and_pc() [here](https://cairo-lang.org/docs/how_cairo_works/functions.html#retrieving-registers).
    let (local __fp__, _) = get_fp_and_pc();
    return (stack=&new_node);
}

// Adds a node to the top of the stack.
// Returns the updated stack (since Cairo is immutable, you can still use the
// old copy of the stack).
func push(stack: Node*, value: felt) -> (stack: Node*) {
    alloc_locals;
    local new_node: Node;
    // Fix and uncomment below.
    // assert new_node.next = ...
    // assert new_node.value = ...
    // assert new_node.size = ...

    let (__fp__, _) = get_fp_and_pc();
    return (stack=&new_node);
}

// Removes the top element of the stack.
// Returns the updated stack and the element that was removed.
func pop(stack: Node*) -> (stack: Node*, value: felt) {
    return (stack=stack.next, value=stack.value);
}

// Returns the value of the n-th element from the top of the stack.
func stack_at(stack: Node*, n: felt) -> (value: felt) {
    if (n == 0) {
        // Add your code here.
    }

    // Add your code here.
}

func main() -> () {
    alloc_locals;
    // Start with an empty stack.
    let (stack) = empty_stack();
    // Push 1, 10, 100.
    let (stack) = push(stack, 1);
    let (stack) = push(stack, 10);
    let (local stack) = push(stack, 100);

    // Check the size of the stack.
    assert stack.size = 3;

    // Query the stack at indices 0, 1 and 2.
    let (value) = stack_at(stack, 0);
    assert value = 100;
    let (value) = stack_at(stack, 1);
    assert value = 10;
    let (value) = stack_at(stack, 2);
    assert value = 1;

    // Pop the top 2 values (100 and 10) and push 1000.
    let (stack, value) = pop(stack);
    assert value = 100;
    let (stack, value) = pop(stack);
    assert value = 10;
    let (local stack) = push(stack, 1000);

    // Query the stack at indices 0 and 1.
    let (value) = stack_at(stack, 0);
    assert value = 1000;
    let (value) = stack_at(stack, 1);
    assert value = 1;

    return ();
}
```

---

> Answers to this question are a part of the ✨ 17 days of Cairo Lang with Playground & Newton. ✨
> 

*Vote for your favorite answer - the best answer will win a $10 award. A new day – a new reward! During the next 17 days, our goal is to attract more developers to the Cairo language and to systematize the knowledge of Cairo lang. [Read rules](https://www.notion.so/17-days-of-Cairo-Lang-with-Newton-550dfcda6a2d449ca468be293c776578)*

How to create Structs in Cairo Lang for StarkNet?

Hi, 
Would anyone have a link or know how fast blocks would be generated on StarkNet after Regenesis ?
I am working on a project where I mint an NFT which can be burnt to mint other NFTs. Hence, I'd like to know how much minimum time there will be between these two mints transactions.

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

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