exec

Call a contract function, encoding the arguments from its signature.

Supports runtime fields inside smart blocks. Use explicit @helper! expressions or captured outputs; other fields are evaluated at build time.

Syntax

exec <contractAddress> <signature> [...params]

Arguments

Name	Type	Evaluation	Description
`contractAddress`	`address`	Runtime in smart blocks	Target contract address
`signature`	`write-abi`	Build time	Function signature (e.g. `"transfer(address,uint256)"`)
`[...params]`	`any`	Runtime in smart blocks	Arguments matching the signature types

Options

Name	Type	Evaluation	Description
`--value`	`number`	Runtime in smart blocks	ETH to send with the call (in wei)
`--from`	`address`	Build time	Sender address (requires simulation or connected wallet)
`--gas`	`number`	Build time	Gas limit
`--max-fee-per-gas`	`number`	Build time	Max fee per gas (EIP-1559)
`--max-priority-fee-per-gas`	`number`	Build time	Max priority fee per gas (EIP-1559)
`--nonce`	`number`	Build time	Transaction nonce override

Examples

# Approve a token
exec @token(DAI) "approve(address,uint256)" 0x64c007ba4ab6184753dc1e8e7263e8d06831c5f6 1200e18

# Send ETH with the call
exec 0xe91d153e0b41518a2ce8dd3d7944fa863463a97d "deposit()" --value 1e18

# Specify sender
exec @token(DAI) "approve(address,uint256)" 0x64c007ba4ab6184753dc1e8e7263e8d06831c5f6 1200e18 --from 0x44fA8E6f47987339850636F88629646662444217

# Capture events from the transaction
load sim
set $wxdai 0xe91d153e0b41518a2ce8dd3d7944fa863463a97d
sim:fork --using anvil (
  sim:set-balance @me 1e18
  exec $wxdai "deposit()" --value 0.001e18 -> Deposit(address indexed, uint) [_ $amount]
  exec $wxdai "withdraw(uint)" $amount
)

# Complex parameter types
exec 0xd0e81E3EE863318D0121501ff48C6C3e3Fd6cbc7 "addBatches(bytes32[],bytes)" [0x02732126661d25c59fd1cc2308ac883b422597fc3103f285f382c95d51cbe667] @bytes(QmTik4Zd7T5ALWv5tdMG8m2cLiHmqtTor5QmnCSGLUjLU2)

Revert Captures

Revert captures (-!> / -?!>) catch transaction reverts and decode the error data into variables. Three forms are available after the error name: nothing (assertion only), destructure ([...]), or a boolean variable ($var). A failure raised before the transaction is sent — an argument that will not encode, a read that reverts in an inline call — is a refusal of the line and is caught with -/> / -?/> instead; a revert capture lets it through untouched.

set $c 0x44fA8E6f47987339850636F88629646662444217

# Assert a specific error without capturing data
exec $c "deny()" -!> Unauthorized()

# Destructure error arguments into variables
exec $c "withdraw(uint256)" 200 -!> InsufficientBalance(uint256,uint256) [$balance $required]

# Catch a require/revert reason
exec $c "transfer(address,uint256)" @me 100e18 -!> Error(string) [$reason]

# Boolean variable: $e is "true" if the error matched
exec $c "deny()" -!> Unauthorized() $e

# Generic catch-all (no error name)
exec $c "doSomething()" -!> [$reason]
exec $c "doSomething()" -!> $e

# Optional: skip silently if tx succeeds
exec $c "maybeRevert()" -?!> Error(string) [$reason]
exec $c "maybeRevert()" -?!> Unauthorized() $e  # $e = "false" if tx succeeds or wrong error

-!> expects the transaction to revert; throws if it succeeds
-?!> captures the error if the tx reverts; silently continues if it succeeds
With a boolean variable ($e), -?!> sets $e = "false" on success or mismatched error; -!> always sets $e = "true" (throws otherwise)
Supported error types: custom named errors from the target's ABI, Error(string) (require/revert), Panic(uint256) (assert), and empty reverts
Use -/> / -?/> for a failure raised before the send; see Captures

Notes

The signature follows Solidity syntax: "functionName(type1,type2)"
Parameters are automatically ABI-encoded based on the signature
Use --value to send ETH with the call
Use --from to impersonate a sender (requires simulation mode)
Event captures (->) execute the transaction immediately and store decoded log values in variables
Revert captures (-!> / -?!>) catch and decode transaction reverts; refusal captures (-/> / -?/>) catch a failure raised before the send