If my understanding is correct,the cross chain bridge doesn't generate its own blocks, the transactions it generates are packed into blocks in starknet and eventually delivered to the ethereum mainnet, this's its mechanism, pls check: https://docs.starknet.io/docs/L1-L2%20Communication/token-bridge/ thank you🤝 😀

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

Newton

does cross-chain bridge produce its own block? or it only verify the blocks from A/B chain?

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

Does cross-chain bridge produce its own block? Or it only verify the blocks from A/B chain?

How can I resolve this issue?


I'm trying to prove that the left uint is smaller than the right uint using this function:


`func main(syscall_ptr : felt*, pedersen_ptr : HashBuiltin*, range_check_ptr):`


 `let zero = Uint256(0, 0)`


 `let one = Uint256(1, 0)`


 `let (result) = uint256_signed_lt(zero, one)`


`end`


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/308)_

Cairo Error: 'range_check_ptr' cannot be used as an implicit return value. Consider using a 'with' statement.

How do I use keccak functions in Cairo? I am getting the error `Unknown identifier 'bitwise_ptr'` 


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/662)_

Cairo error: Unknown identifier 'bitwise_ptr' when using keccak

Hello! This is day 17 of the 17 days of the Cairo Challenge. In this challenge I want to ask you [install](https://www.cairo-lang.org/docs/quickstart.html) Cairo and try to launch your first program. What have you implemented as your first Cairo language program?

**Step 1**
```solidity
// 1. Make sure that you installed dev packages on your device
sudo apt install -y libgmp3-dev // Linux
brew install gmp // Mac OS
```
**Step 2**
```solidity
// 2. Install Cairo using Python virtual environment
python3.9 -m venv ~/cairo_venv
source ~/cairo_venv/bin/activate
pip3 install ecdsa fastecdsa sympy;
pip3 install cairo-lang;
```
**Step 3**
```bash
// 3. Make sure you have python 3.9. Because Cairo was tested with python3.9. To make it work with python3.6, you will have to install contextvars:
pip3 install contextvars
```
**Step 4**
```python
// 4. Write your program
// Create a file, named hello.cairo, with the following lines:
 
func main() {
		// edit me: you can add here any output, best program wins the challenge
    ret;
}

```solidity
//5. Compile your program
cairo-compile hello.cairo --output hello_compiled.json
```
**Last step**
```solidity

//6. Run:
cairo-run \
  --program=hello_compiled.json --print_output \
  --print_info --relocate_prints

//7. Debug:
//You can open the Cairo tracer by providing the --tracer flag to cairo-run. Then open it at http://localhost:8100/.
```
If you have questions, create them on Newton and we will help!

---
> 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 install Cairo v0.10.0 on my device?

Hi! I like writing my Cairo code in vim. However, I don't like that Cairo lang code has no auto-format and syntax highlighting (see screenshot):

![https://sun9-86.userapi.com/impg/oNPtr4oks9yNwg3MDoX8c5b-B4IBgK1DARpTbg/RJgXBHR3mEY.jpg?size=1242x682&quality=96&sign=3390ee79c30971ba0dc245122af04905&type=album](https://sun9-86.userapi.com/impg/oNPtr4oks9yNwg3MDoX8c5b-B4IBgK1DARpTbg/RJgXBHR3mEY.jpg?size=1242x682&quality=96&sign=3390ee79c30971ba0dc245122af04905&type=album)

I'm looking for a plugin to write Cairo contracts on Starknet in vim with all pretty formatting. Can you recommend any and how to install it as well?



Does anyone know a vim plugin for StarkNet smart contracts?

Can someone explain the difference `between unsigned_div_rem` and `uint256_unsigned_div_rem`?

Why unit version process so many extra steps, but overall number of steps for computing are different for these methods?



Can someone explain the difference between unsigned_div_rem and uint256_unsigned_div_rem?

Is it possible to use Solidity's abi.encode and abi.decode in Cairo? Our periphery contract uses these 2 functions in EVM to send a tx to the core contracts, and then if a condition is met the core contract calls back the router like so:

router -> core -> router

An example of this can be found here: 

**router:**
https://github.com/CygnusDAO/periphery/blob/main/contracts/cygnus-periphery/CygnusAltairX.sol#L758

**core:**
https://github.com/CygnusDAO/core/blob/main/contracts/cygnus-core/CygnusBorrow.sol#L145

Thanks!

Abi.encode and Abi.decode in Cairo?

### How to fix this?

```python
./main.cairo:23:13: While expanding the reference 'bud_ptr' in:
    bud=bud,
            ^*****^
./main:20:9: Error at pc=0:2482:
Unknown value for memory cell at address 1:8.
```

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Does cross-chain bridge produce its own block? Or it only verify the blocks from A/B chain?

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