Defining classes in eopsin

[nielstron]

When defining new classes for use inside eopsin, note the following

@dataclass()
class Deposit(PlutusData):
    CONSTR_ID = 0
    minimum_lp: int


@dataclass()
class Withdraw(PlutusData):
    CONSTR_ID = 1
    minimum_coin_a: int
    minimum_coin_b: int


OrderStep = Union[Deposit, Withdraw]

1. The structure of a class definition has to strictly follow this setup

@dataclass
class FooClass(PlutusData):
   attr1: type1
   attr2: type2

That is 1. is has to be tagged as dataclass 2. it has to inherit from PlutusData 3. the CONSTR_ID is optional but needs to be assigned a constant integer if set 4. all other attributes are listed and annotated with a type, but never set to a default value.

Also, if you want to create and use a union of dataclasses, make sure they have different CONSTR_IDs!

Check the documentation on dataclasses if you are unfamiliar with how they work: https://docs.python.org/3.8/library/dataclasses.html

[nielstron]

The prelude contains many different classes defined in valid eopsin code, check it out for more examples.

[while0x1]

I have used some custom classes but am encountering a compiler error which I am trying to narrow down -

return compile(source, filename, mode, flags,
File "", line 81
if i.winnerhash in ctx.tx_info.signatories

#from dataclasses import dataclass, field, asdict
#from typing import List

from eopsin.prelude import *

@dataclass
class winner(PlutusData) :
     winnerhash: bytes
     lovelace: int

@dataclass
class winnerList(PlutusData):
     winners: List[winner]
     
#@dataclass
#class winner:
#     winnerhash: bytes
#     lovelace: int

#@dataclass
#class winnerList:
#     winners: List[winner]
     

#winnerDetails = winnerList([winner(b"abc",1000000),winner(b"def",2000000)])
#assert asdict(winnerDetails) == {[{'winnerhash': b"abc", 'lovelace': 1000000},{'winnerhash': b"def", 'lovelace': 2000000}]}
#for n in winnerDetails.winners:
#    print(n.lovelace)

ENTRY-POLICY=b"\x11\x22\x33"
WIN-POLICY=b"\x44\x55\x66"

#TODO- make sure the entry-policy token is being sent to the contract address i.e) cannot be used twice

def validator(datum: None, redeemer: None, context: ScriptContext) -> None:
    tx_inputs = context.tx_info.inputs
    entry_present = entry_policy_present(tx_inputs)
    win_present = win_policy_present(tx_inputs)
    winningDatum = getWinnersDatum(tx_inputs)
    allowSpend = check_winners(winningDatum,context)
    assert entry_present and winpresent and allowSpend, "No Entry Policy, No Winners Defined or Incorrect Prize Claimed"
	

def own_spent_utxo(txins: List[TxInInfo], p: Spending) -> TxOut:
    # obtain the resolved txout that is going to be spent from this contract address
    for txi in txins:
        if txi.out_ref == p.tx_out_ref:
            own_txout = txi.resolved
    # This throws a name error if the txout was not found
    return own_txout
	
def entry_policy_present(txins: List[TxInInfo]) -> Bool:
    res = False
    for txi in txins:
        if txi.resolved.value.get(token.policy_id, {b"": 0}) == ENTRY-POLICY:
            res = True
    return res
	
def win_policy_present(txins: List[TxInInfo]) -> Bool:
    res = False
    for txi in txins:
        if txi.resolved.value.get(token.policy_id) == WIN-POLICY:
            res = True
    return res

def getWinnersDatum(txins: List[TxInInfo]) -> WinnerList:
    res = {}
    for txi in txins:
        if txi.resolved.value.get(token.policy_id) == WIN-POLICY:
            res = txi.datum
    return res
	
def check_winners(win: WinnerList, ctx: ScriptContext) -> Bool:
    res = False
    txouts = ctx.tx_info.outputs
    purpose = ctx.purpose
    allow_spend = 0
    own_utxo = own_spent_utxo(ctx.tx_info.inputs, purpose)
    for i in win.winners:
        if i.winnerhash in ctx.tx_info.signatories
            allow_spend = i.lovelace
    spendingvalue = own_utxo.value.get(b"", {b"":0}).get(b"",0)
    res = spendingvalue == allow_spend
    return res

[nielstron]

Ah there is also a syntax error close to the end. check the if.

[nielstron]

I recommend using a proper IDE for this. It's just python syntax, basically every IDE supports this.

[nielstron]

Regarding checking whether ENTRY_POLICYID in values.keys(), I just bumped the version with something that should work with that, see https://github.com/ImperatorLang/eopsin/blob/dev/examples/dict_datum.py for example usage.

[while0x1]

Thanks! without a practical example the source code doesnt help a newbie like me very much but Il experiment and see if I can get it to work

[nielstron]

I did not link source code but a practical example :)

[while0x1]

Thanks - all rookie mistakes - VsCode caught the lack of : in the if statement - thanks for all the help and suggestions!

[while0x1]

for reference the following is the code which successfully compiles after removing all of the bugs and using eopsin-lang-0.7.7

#from dataclasses import dataclass, field, asdict
#from typing import List

from eopsin.prelude import *

@dataclass()
class winner(PlutusData):
    winnerhash: bytes
    lovelace: int
    
@dataclass()
class winnerList(PlutusData):
    winners: List[winner]

#@dataclass
#class winner:
#     winnerhash: bytes
#     lovelace: int

#@dataclass
#class winnerList:
#     winners: List[winner]
    
#winnerDetails = winnerList([winner(b"abc",1000000),winner(b"def",2000000)])
#assert asdict(winnerDetails) == {[{'winnerhash': b"abc", 'lovelace': 1000000},{'winnerhash': b"def", 'lovelace': 2000000}]}
#for n in winnerDetails.winners:
#    print(n.lovelace)

ENTRY_POLICY= b"\x11\x22\x33"
WIN_POLICY= b"\x44\x55\x66"
ENTRY_POLICY_NAME = b"VeriFair"
WIN_POLICY_NAME = b"VeriFairWinners"

ENTRY_TOKEN = Token(ENTRY_POLICY, ENTRY_POLICY_NAME)
WIN_TOKEN = Token(WIN_POLICY, WIN_POLICY_NAME)

#TODO- make sure the entry-policy token is being sent to the contract address i.e) cannot be used twice

def own_spent_utxo(txins: List[TxInInfo], p: Spending) -> TxOut:
    # obtain the resolved txout that is going to be spent from this contract address
    for txi in txins:
        if txi.out_ref == p.tx_out_ref:
            own_txout = txi.resolved
    # This throws a name error if the txout was not found
    return own_txout
	
def entry_policy_present(txins: List[TxInInfo],token: Token) -> bool:
    res = False
    for txi in txins:
        if txi.resolved.value.get(token.policy_id, {b"": 0}).get(token.token_name, 0) > 0:
            res = True
    return res
	
def win_policy_present(txins: List[TxInInfo],token: Token) -> bool:
    res = False
    for txi in txins:
        if txi.resolved.value.get(token.policy_id, {b"": 0}).get(token.token_name, 0) > 0:
            res = True
    return res

#def getWinnersDatum(txins: List[TxInInfo],token: Token) -> winnerList:
#    for txi in txins:
#        if txi.resolved.value.get(token.policy_id, {b"": 0}) == WIN_POLICY:
#            res = winnerList(txi.resolved.datum)
#        #TypeInferenceError: Type TxInInfo does not have attribute datum
#    return res
	
def getPrizeValue(win: winnerList, ctx: ScriptContext) -> int:
    allow_spend = 0
    txouts = ctx.tx_info.outputs
    purpose = ctx.purpose
    for i in win.winners:
            if i.winnerhash in ctx.tx_info.signatories:
                allow_spend = i.lovelace
    #allow_spend = 10
    return allow_spend

def validator(datum: None, redeemer: None, context: ScriptContext) -> None:
    tx_inputs = context.tx_info.inputs
    entry_present = entry_policy_present(tx_inputs,ENTRY_TOKEN)
    win_present = win_policy_present(tx_inputs,WIN_TOKEN)
    winnerDetails = winnerList([winner(b"abc",1000000),winner(b"def",2000000)])
    #winningDatum = getWinnersDatum(tx_inputs,WIN_TOKEN)
    purpose = context.purpose
    if isinstance(purpose, Spending):
        own_utxo = own_spent_utxo(context.tx_info.inputs, purpose)
        
    spendingValue = own_utxo.value.get(b"", {b"":0}).get(b"",0)
    prizeValue = getPrizeValue(winnerDetails,context)
    correctPrizeClaim = spendingValue == prizeValue

    allowSpend = correctPrizeClaim and entry_present and win_present
            
    assert allowSpend, "No Entry Policy, No Winners Defined or Incorrect Prize Claimed"