DAML is a smart contract language developed by Digital Asset that is designed to simplify the process of creating and managing complex financial agreements. It is an open-source language that uses a functional programming paradigm and is built on top of Haskell. While DAML Cheat Sheet is relatively easy to learn, it can still be challenging for beginners to remember all of the syntax and semantics of the language. That’s where a DAML cheat sheet comes in handy.
In this article, we’ll provide a comprehensive DAML cheat sheet to help you quickly reference the most important concepts and syntax of the language.
Data Types and Declarations of DAML Cheat Sheet
DAML is a statically-typed language, which means that variables must be declared with their data type before they can be used. The following data types are supported in DAML:
- Int: an integer value
- Text: a string of characters
- Bool: a Boolean value (true or false)
- Decimal: a fixed-point decimal value
- Party: a participant in a DAML contract (e.g., a person or organization)
- Time: a timestamp
- List: a list of values of the same data type
- Map: a mapping between keys and values of different data types
Variable Declaration
To declare a variable in DAML Cheat Sheet, you must specify its data type, followed by its name. For example:
VBnet
let x: Int = 42
let y: Text = "Hello, world!"
let z: Bool = true
You can also declare multiple variables of the same type on the same line, separated by commas:
CSS
let a, b, c: Int = 1, 2, 3
Functions
In DAML, functions are first-class citizens, which means that they can be passed as arguments to other functions and returned as values. To define a function in DAML Cheat Sheet, use the daml
keyword, followed by the function name, its arguments, and its return type. For example:
SQL
daml add(x: Int, y: Int): Int = x + y
This function takes two integer arguments (x
and y
) and returns their sum.
Conditional Statements
Conditional statements in DAML Cheat Sheet are similar to those in other programming languages. To perform a conditional check, use the if
keyword, followed by the condition in parentheses. For example:
Python
if x > y then "x is greater than y" else "y is greater than or equal to x"
Loops
DAML supports several types of loops, including for
loops and while
loops. The syntax for these loops is similar to that of other programming languages. For example:
Java
for i in 1..10 do
-- do something with i
while x > 0 do
-- do something with x
Lists
Lists are a commonly used data structure in DAML. To create a list, use square brackets ([]
) and separate the elements with commas. For example:
Java
let lst: List Int = [1, 2, 3, 4, 5]
You can also append elements to a list using the ++
operator:
Java
let lst2: List Int = lst ++ [6, 7, 8, 9, 10]
Maps
Maps are another commonly used data structure in DAML. To create a map, use curly braces ({}
) and separate the key-value pairs with commas. For example:
Java
let map: Map Text Int = {"one": 1, "two": 2, "three": 3}
You can access and modify map values using the following syntax:
let val1 = map["one"]
let map2 = map with ["one" <- 4]
The first line retrieves the value associated with the key "one"
from the map
variable. The second line creates a new map called map2
that has the value associated with the key "one"
replaced with the value 4
.
Templates
Templates are the building blocks of DAML contracts. They define the data structure and behavior of a contract. To create a new template, use the template
keyword, followed by the template name and its fields. For example:
template Token
with
owner: Party
symbol: Text
quantity: Int
where
signatory owner
ensure quantity > 0
This template defines a new token contract that has an owner, a symbol, and a quantity field. The signatory
keyword specifies that the owner of the contract is also the party that is authorized to sign it. The ensure
keyword specifies that the quantity of tokens must be greater than 0.
Contracts
Contracts in DAML represent agreements between parties. They are created from templates and are updated through a series of commands. To create a new contract, use the create
keyword, followed by the name of the template and its fields. For example:
SQL
create Token with owner = Alice, symbol = "ABC", quantity = 100
This command creates a new Token
contract with Alice as the owner, the symbol "ABC"
, and a quantity of 100.
Commands
Commands in DAML are used to update the state of contracts. They can be used to create, archive, or exercise contracts. To execute a command, use the submit
keyword, followed by the command. For example:
submit create Token with owner = Alice, symbol = "ABC", quantity = 100
This command creates a new Token
contract with Alice as the owner, the symbol "ABC"
, and a quantity of 100.
Conclusion
DAML is a powerful and flexible programming language that is specifically designed for creating and managing complex financial contracts. While it can be challenging to learn, a DAML cheat sheet can be an invaluable resource for both beginners and experienced developers.
The cheat sheet provided in this article covers the most important concepts and syntax of the language, including data types, functions, conditional statements, loops, lists, maps, templates, contracts, and commands. With this cheat sheet at your fingertips, you’ll be able to quickly reference the syntax and semantics of DAML Cheat Sheet and create powerful and secure financial contracts with ease.