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Smart Contract Language

Archethic Blockchain defines a new smart contract language which was designed to resolve the issue of smart contracts:

  • Expressiveness
  • Simplify
  • Security

Along with the new features of Archethic Smart Contracts (triggers, conditions, actions), a new custom language is defined

Triggers/Actions

To define a trigger, we need to specify an action block with its trigger type and the following parameters (if presents)

For example:

  • based on an incoming transaction
actions triggered_by: transaction do
# do something when a receive transaction
end
  • based on time interval
actions triggered_by: interval, at: "0 8 * * *" do
# do something each day at 8AM
end

Conditions

To define a condition, we need to specify a condition block with its subject and the list conditions by fields:

  • type
  • content
  • code
  • authorized_keys
  • secrets
  • uco_transfers
  • token_transfers
  • previous_public_key
  • origin_family

For example:

  • expecting the incoming transaction contains the content "hello"
condition transaction: [
content: "Hello"
]
  • expecting all the transaction in the chain should be generated from a biometric device
condition inherit: [
origin_family: biometric
]

Global variables

Smart Contract can use global variable in the different blocks:

  • contract: represent the actual contract
  • transaction: incoming transaction
  • (inherit condition only) next: next transaction on the chain
  • (inherit condition only) previous: previous transaction on the chain

Each of this variables contains the following fields:

  • address (hex)
  • type
  • content (abitraty string)
  • code (abritraty string)
  • authorized_keys (map of public keys)
  • secrets (list of encrypted secrets in hex)
  • previous_public_key (hex)
  • recipients (list of smart contract recipients addresses in hex)
  • uco_transfers (map of the uco transfers: %{ recipient_address => amount }
  • token_transfers (map of the token transfers: %{ recipient_address => list(%{ amount: amount, token_address: token_to_transfer, token_id: token_id}})

Functions

Archethic Smart Contracts relies on function which can be used on condition or action blocks.

There are two categories of functions:

  • Utilities
  • Statements (for transaction generation)

Utilities

info

In the condition block, if no parameter is given, the transaction's field value will be the first one

  • hash(data): Perform a cryptographic hash
condition transaction: [
content: hash(contract.code)
]
  • regex_match?(data, pattern): Verify a regular expression
condition transaction: [
content: regex_match?("hello")
]
  • regex_extract(data, pattern): Extract data from a regular expression

  • json_match?: Verify the data matches a JSONPath expression

condition oracle: [
content: json_match?("$.uco.usd")
]
  • json_extract(data, pattern): Extract data from a JSONPath expression
condition oracle: [
content: json_extract("$.uco.usd") > 0.2
]

Statements

  • set_type: Set the transaction type
actions triggered_by: transaction do
set_type transfer
end
  • add_uco_transfer: Add a new UCO transfer
actions triggered_by: transaction do
add_uco_transfer to: "F28C3D5B3828AD3F8682F1B1D14A8507B829F65F7BE6C50427A6019CCB6801C", amount: 1.0
end
  • add_token_transfer: Add a new token transfer
actions triggered_by: transaction do
add_token_transfer: to: "AF28C3D5B3828AD3F8682F1B1D14A8507B829F65F7BE6C50427A6019CCB6801C", token_address: "0D574D171A484F8DEAC2D61FC3F7CC984BEB52465D69B3B5F670090742CBF5CC", amount: 1.0
end
  • set_content: Set the new content
actions triggered_by: transaction do
set_content "hello"
end
  • set_code: Set the new code
actions triggered_by: transaction do
set_code """
actions triggered_by: transaction do
add_uco_transfer to: "0D574D171A484F8DEAC2D61FC3F7CC984BEB52465D69B3B5F670090742CBF5CC", amount: 2.0
end
"""
end
  • add_ownership: Add a new ownership with a secret and its authorized public keys
actions triggered_by: transaction do
add_ownership secret: "...", secret_key: "...", authorized_public_key: ["0D574D171A484F8DEAC2D61FC3F7CC984BEB52465D69B3B5F670090742CBF5CC"]
end
  • add_recipient: Add a contract address to reach
actions triggered_by: datetime, at: 1391309030 do
add_recipient "0D574D171A484F8DEAC2D61FC3F7CC984BEB52465D69B3B5F670090742CBF5CC"
end