Questions tagged [smartpy]
Discussion about the SmartPy language
103
questions
2
votes
1answer
7 views
how to get the current time/timestamp in smartpy contract?
I deployed a smartpy contract in florencenet via smartpy.io. The command sp.timestamp_from_utc_now() used insed the program seems to be not giving the current time. Instead it is giving the same time ...
0
votes
0answers
18 views
How can we accept USDTZ in smartpy smart contracts, is it even posible?
I was working on a token sale, so is there any way we can accept USDTZ as a mode of payment for the tokens?
0
votes
0answers
23 views
+50
Mint FA2 NFT when contract is called by purchaser
I'm working on a smart contract which allows a caller to "purchase" an NFT simply by calling the contract and providing payment. I'd like the contract to mint the NFT at the time the ...
1
vote
1answer
14 views
Getting error at time of testnet deployment
I was familiarising with smartpy IDE by executing the code as mentioned in the below link
https://tezos.b9lab.com/smartpy/exercise-2
However, when I proceeded to deploy the contract, I am getting the ...
0
votes
1answer
63 views
Converting a hash into an int within a range
I have a contract where I'd like to convert a hash (sha256 in this case, but I'm open to any of the other hashing algorithms available) into an Int (or Nat) between 1 and 100.
I have the code that ...
2
votes
1answer
74 views
Limiting the time (time/date based) that a contract method can be called
I'd like to publish a contract that allows calls up until a certain time and date.
For example, say I want to allow anyone to call it for 1 year after publishing the contract to the blockchain, then ...
1
vote
1answer
30 views
Using sp.create_contract to generate pseudorandom numbers on-chain
In this answer, the answerer suggested that CREATE_CONTRACT could be used to generate a contract address which could then be used as a seed for a pseudorandom number in a contract.
What would a simple ...
1
vote
1answer
31 views
Tweaking FA1.2 to add level based balance snapshots to assist token voting in a DAO
DAOs functioning on a token voting mechanism (using either FA1.2 or FA2) mostly require the locking up of tokens for the entirety of the voting period essentially to prevent double-voting or any form ...
2
votes
1answer
23 views
Smartpy Michelson errors only on deployment (inconsistent_annotations, inconsistent_types)
Getting this error ONLY when deploying the smartpy contract. There are otherwise no errors when testing/compiling the code. Is there a way to get a better error message? Is there a way to trigger ...
0
votes
1answer
14 views
error Type sp.TInt / sp.TNat mismatch
Error: Type sp.TInt / sp.TNat mismatch
sp.is_nat expects a sp.TInt
Got: sp.TNat
line 119
Line: 119
self.data.shop_items[item_to_purchase.key].amount -= sp.as_nat(item_to_purchase.value)
I'm ...
0
votes
1answer
28 views
Error: list indices must be integer, not Expr
I am trying to get the first N prime numbers in the following way:
@sp.entry_point
def n_primes(self, num):
primes = [2]
p = sp.local("p", 1)
i = sp.local("i&...
2
votes
1answer
25 views
Smart contract break for loop in smartpy
I need to break a for loop in smartpy, but break does not work.
Is there any other solution I could use?
1
vote
2answers
27 views
Keeping original sender in inter-contract call
I have a token contract (let's say it TC) and creating a contract Wallet. Now, is it possible for a user to call Wallet's entrypoint deposit which will do an inter-contract call to TC's transfer ...
1
vote
3answers
33 views
Big map of map vs Big map of pairs
In the FA2 example (https://smartpy.io/ide?template=FA2.py) with multiple assets, we are using a big map of pairs (of user and token). Another option might be storing big map mapping users to another ...
0
votes
0answers
22 views
how to work with map of map
I have a structure that looks like this:
struc = sp.TRecord(
addr = sp.TAddress,
value = sp.TNat
)
struct2 = sp.big_map(
tkey=sp.TAddress,
tvalue=sp.TMap(
sp.TNat,
sp....
2
votes
1answer
41 views
Variable callback entrypoint in smartpy
Is it possible to use a variable as the entry_point for a callback in smartpy?
This works:
@sp.entry_point
def getProofs(self, address, callback_address):
c = sp.contract(...
0
votes
1answer
20 views
sp.if not working as it should
I am using sp.if in an internal function, then I call it in an entry point, but whatever I enter in sp.if, it always is read as "True". Why? And how to fix it?
My code :
def is_something(...
0
votes
2answers
41 views
What's the best IDE and language to create a FA2 Token?
Does SmartPy provide the best interface to do it?
https://smartpy.io/ide?template=FA2.py
Does this example provide everything you need to create your own token?
Any help would be appreciated.
0
votes
0answers
16 views
Can anyone refer me to a good code example that creates a Token crowdfunding STO/IDO/ICO contract in Tezos?
Can anyone refer me to a good code example that creates a Token crowdfunding STO/IDO/ICO contract in Tezos? (Comparable to ERC-20 crowdfunding contracts)
1
vote
2answers
70 views
Why is this big map update using up so many bytes?
In this question I asked why so much Tezos was burned when updating 380 cells in a grid.
It's surprising to see how many bytes it actually took though. If you look at the transaction, there were 380 ...
1
vote
1answer
71 views
Best way to create FA1.2 token with TZIP016
What is the best way to implement a FA1.2 token with TZIP-016 metadata (symbol, name, decimals...)?
I am using SmartPy.
So far, I noted two methods:
the first one is to implement a FA1.2 token with a ...
1
vote
1answer
43 views
How can I encode a 2D matrix of booleans in the least amount of bytes?
I'm looking at this ethereum smart contract that iterates over an area in a 2D bool matrix to reserve pixels. When looking at a call to that ethereum smart contract for a 20x11 area, it used 0.0315 ...
1
vote
1answer
33 views
What would be the simplest way to connect a smartpy contract to an oracle tracking the XTZ/USD pair?
I see there's a smartpy chainlink oracle example and a github repo for Harbinger. I briefly looked at the code and it appears they are for setting up Oracles + clients. Are there any existing XTZ/USD ...
2
votes
1answer
55 views
How should a contract check whether an address owns a FA2 token created in another contract?
I've broken up my code into 2 contracts. FA2 contract and other one managing its data and providing additional functionality on top. This is to not overload a single contract, however, it does ...
2
votes
1answer
92 views
Is there a list of public repos using smartpy?
I'd like to see more complex examples of smartpy being used in main net contracts.
So far, I've found tzcolor's auction house contract SUPER helpful. Are there any other really good examples (that are ...
1
vote
1answer
73 views
How do offchain views work and what guarantees do they provide?
What are the technical differences between offchain views vs onchain entry points? I know one of the differences is that onchain entry points mutate while offchain views don't. Are there any other ...
1
vote
1answer
42 views
How to add new record fields in data storage after contract deployment? Is storing JSON in a field viable?
AFAIK, there is no way to update storage types(ex: can't add a new record field to a Map<sp.Nat, sp.record(a=1)>) of a contract after deployment. (Correct me if I'm wrong). This means, after a ...
1
vote
1answer
21 views
Does smartpy propagate exceptions?
I'm doing something like this, but the invalid scenario assertion fails.
Is there a way to propagate the exception from the other contract? Or do I just have to test that contract separately?
class ...
1
vote
1answer
43 views
What are good examples of upgradable smartpy contracts using Proxy delegates or stored lambdas?
I'm trying to ensure my contract is upgradable and I learn best by looking at existing examples. Does anyone have any good examples to look at?
Here are some links to previous stackoverflow Q&A's ...
0
votes
1answer
19 views
Incompatible parameter error when calling another smart contract
I'm getting this weird error when trying to call the mint entrypoint from another contract... I had additional parameters in the BuyLandRequest and was overriding the TezosHomepageAdNft.mint ...
2
votes
1answer
59 views
Why aren't the offchain views appearing?
I'm extending the smartpy FA2 template
#
FA2 = sp.import_script_from_url("https://smartpy.io/dev/templates/FA2.py")
class TezosLandNft(FA2.FA2):
...
which has the following offchain views ...
0
votes
1answer
30 views
How can I do string interpolation on smartpy?
I'm trying to provide better error messages. I've tried several things already that don't work such as regular python fstrings, regular string concatenation. I'm tried to using the sp.string function ...
2
votes
1answer
120 views
How to store and load custom FA2 NFT metadata?
First time I'm writing a smart contract. If anything doesn't make sense at all, feel free to call out what specifically doesn't make sense and suggest a better approach. Thanks!
At a high level I just ...
1
vote
2answers
94 views
Best Language to Use with Tezos
There are a lot of options when it comes to coding Smart Contracts on Tezos. My question is simple, which of the supported languages is the best in terms of support, east of use, documentation, and ...
0
votes
1answer
28 views
import_script_from_url syntax
i'd like to ask if it's possible to load another smart contract from an IPFS Hash or from a SmartPy url. What would be the best way to handle them with urls?
Contract A: https://smartpy.io/ide?cid=...
0
votes
1answer
40 views
Smartpy transfer contract balance to an address
I'm trying to figure out how to withdraw money from the contract within a smartpy entrypoint, and test the result in my scenario.
When I test the entrypoint:
@sp.entry_point
def withdraw(self, ...
0
votes
1answer
17 views
Is SmartPy package inside All Michaelson Supported Languages?
I've discovered that Liquidity, LigoLang and Ocamel Support Tezos development, but I've only found 1 resource that states that SmartPy supports only LigoLang. I wanted to use the right language to ...
-1
votes
1answer
52 views
Tezos SmartPy Developer Course video 1.2
How do I get find the Tezos test net as opposed to the web browser smart py interface?
Regards
WF
1
vote
1answer
28 views
How to compare a mutez value with int in smartpy
When trying to check the transferred value is positive I get an error that TMutez is not TIntOrNat.:
sp.verify(sp.amount > 0, "Amount should be positive")
1
vote
1answer
63 views
SmartPy Contract: Receive a balance?
I'm learning SmartPy and I'm trying to make a simple escrow contract. I read that contract.balance can be used to access the balance of a contract. In that case, how would I go about receiving XTZ to ...
1
vote
1answer
39 views
How to resolve sp.TKey is not sp.TAddress error in SmartPy?
I have a function like this
@sp.entry_point
def _verifySigPersonalSign(self,req,sig):
sp.verify((req.deadline != sp.timestamp(0)) | (sp.now<=req.deadline), "request ...
1
vote
1answer
27 views
How to compare timestamps in tezos smartpy?
req passed to _verifySigPersonalSign will be of type ERC
import smartpy as sp
ERC = sp.TRecord(sender=sp.TAddress,to=sp.TAddress,deadline=sp.TTimestamp)
class StoreValue(sp.Contract):
@sp....
2
votes
1answer
38 views
What is the correct usage of sp.unpack()?
*Note that the answer to this question may be very similar to this one.
I tried out the code below within a part of a larger lambda function and got the following error. The purpose is just to convert ...
2
votes
1answer
22 views
How can I avoid sp.TOption type when using sp.unpack()?
Within my smartpy contract, I want to convert from one type into another using sp.pack() and sp.unpack.
Below is an example of the method I am trying to use, converting a string to bytes.
...
1
vote
1answer
51 views
Can a Dapp buy or sell (usdtz or tzbtc) from dexter?
Looking for a way for a dapp to buy tzBTC automatically after receiving tez from a baker.
1
vote
2answers
93 views
Implementing Contract Metadata (tzip-16) on an already originated FA1.2 Smart Contract
Referring to the documents and examples of tzip-16, how would one implement the contract metadata on a Fa1.2 contract on SmartPy? In order to provide balance updates and offchain events.
1
vote
1answer
29 views
What's the best way to convert from TMutez to TBytes?
Previously when I asked about converting types, I got this useful suggestion:
For mutez, you could start to convert to int (by dividing by 1 mutez) and then use the same techniques.
I'm wondering if ...
1
vote
2answers
67 views
How to Integrating SmartPy compiler within the browser?
I have been trying to integrate the SmartPy compiler toolchain within Cryptoverse wars Learning interface and have been going through this video (OCaml Under The Hood: SmartPy) and have encountered ...
1
vote
1answer
37 views
In a SmartPy smart contract, is there 'continue' or 'break' for loop?
In a SmartPy smart contract, is there 'continue' or 'break' for loop?
When I use 'continue' for loop, an error occurred. 'Error: invalid syntax'
1
vote
1answer
47 views
How do you set the time of a transfer when testing contracts with SmartPy?
Previously, to set the (virtual) time a transaction happened in SmartPy I used the flag now when running a command like run. Now it seems to cause an error (seems like something changed in an update). ...
