[Solved] Error: Http request When I try to compile online

æpp Development For Beginners
1

Hello,

I just start learning Sophia and try to compile some existing examples. So I go throught this example of CryptoHamster : https://github.com/aeternity/aepp-sophia-examples/blob/master/examples/CryptoHamster/contracts/crypto-hamsters.aes
but when I copy paste the code to online compilator I get this error:

srr
srr1195×129 8.06 KB

I get the same error when I just try to create my own easy code with just 4lines.
Please any solution? and thank you.

Best Regards

2

Well, the compiler already told you what the problem is. The syntax for tuple types changed in Sophia version 4 and you are trying to compile the old syntax with the new compiler :man_shrugging:

The example is outdated, you have to update () to unit on lines 16 and 29…

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3

@hanssv.chain , Thank you for you answer. it done

4

@hanssv.chain , Please two more question , 1- is there any way to create a random number for example the function keccak256 ?
2- How can I get the block number ?
Thank you so much for your support

5

Thanks @charingane, checkout the documentation on how to get the block number. protocol/sophia.md at master · aeternity/protocol · GitHub

For random numbers, hashes can only offer you pseudo random number generation with specified seed.

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6

Yes, as @philipp.chain mentions, getting a truly random number is not possibly (except using an external part like an oracle) but a pseudo random number you can get from some seed-string like this:

function pseudo_random(seed : string) = Bytes.to_int(String.blake2b(seed))

(if you prefer keccak256/sha3 use String.sha3)

You can also use a recent block hash as the seed:

function pseudo_random() = Bytes.to_int(Crypto.blake2b(Chain.block_hash(Chain.height - 1)))
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