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| -rw-r--r-- | cairo.html.markdown | 48 |
1 files changed, 24 insertions, 24 deletions
diff --git a/cairo.html.markdown b/cairo.html.markdown index faad304a..dd3ca036 100644 --- a/cairo.html.markdown +++ b/cairo.html.markdown @@ -145,7 +145,7 @@ sequence: First let's look at a default contract that comes with Protostar which allows you to set balance on deployment, increase, and get the balance. -```cairo +``` // Language directive - instructs compiler its a StarkNet contract %lang starknet @@ -205,7 +205,7 @@ just a single data type `..felts`. Felts stands for Field elements, and are a 252 bit integer in the range `0<=x<=P` where `P` is a prime number. You can create a `Uint256` in Cairo by utlizing a struct of two 128 bits felts. -```cairo +``` struct Uint256 { low: felt, // The low 128 bits of the value. high: felt, // The high 128 bits of the value. @@ -219,7 +219,7 @@ To avoid running into issues with divisions, it's safer to work with the To get started with writing a StarkNet contract, you must specify the directive: -```cairo +``` %lang starknet ``` @@ -230,7 +230,7 @@ storage, programs don't and as such are stateless. There are important functions you might need to import from the official Cairo-lang library or Openzeppelin's, e.g. -```cairo +``` from starkware.cairo.common.cairo_builtins import HashBuiltin from cairo_contracts.src.openzeppelin.token.erc20.library import ERC20 from starkware.cairo.common.uint256 import Uint256 @@ -243,7 +243,7 @@ from starkware.cairo.common.bool import TRUE slot is a felt which is initialized to `0`. You create one using the `@storage_var` decorator. - ```cairo + ``` @storage_var func names() -> (name: felt) {} ``` @@ -251,7 +251,7 @@ from starkware.cairo.common.bool import TRUE + Storage mappings: Unlike Solidity where mappings have a separate keyword, in Cairo you create mappings using storage variables. - ```cairo + ``` @storage_var func names(address: felt) -> (name: felt) {} ``` @@ -261,7 +261,7 @@ from starkware.cairo.common.bool import TRUE retrieved using `MyStruct.SIZE`. You create a struct in Cairo using the `struct` keyword. - ```cairo + ``` struct Person { name: felt, age: felt, @@ -274,7 +274,7 @@ from starkware.cairo.common.bool import TRUE constant in Cairo, you use the `const` keyword. It's proper practice to capitalize constant names. - ```cairo + ``` const USER = 0x01C6cfC1DB2ae90dACEA243F0a8C2F4e32560F7cDD398e4dA2Cc56B733774E9b ``` @@ -283,7 +283,7 @@ from starkware.cairo.common.bool import TRUE cells. The `alloc` keyword can be used to dynamically allocate a new memory segment, which can be used to store an array: - ```cairo + ``` let (myArray: felt*) = alloc (); assert myArray[0] = 1; assert myArray[1] = 2; @@ -294,7 +294,7 @@ from starkware.cairo.common.bool import TRUE tuples. The new operator is useful as it enables you allocate memory and initialize the object in one instruction - ```cairo + ``` func foo() { tempvar arr: felt* = new (1, 1, 2, 3, 5); assert arr[4] = 5; @@ -306,7 +306,7 @@ from starkware.cairo.common.bool import TRUE represented as a comma-separated list of elements enclosed by parentheses. Their elements may be of any combination of valid types. - ```cairo + ``` local tuple0: (felt, felt, felt) = (7, 9, 13); ``` @@ -314,7 +314,7 @@ from starkware.cairo.common.bool import TRUE execution, that can be used outside of StarkNet. An event can be created, subsequently emitted: - ```cairo + ``` @event func name_stored(address, name) {} @@ -327,7 +327,7 @@ from starkware.cairo.common.bool import TRUE contract deployment. You create a constructor using the `@constructor` decorator. - ```cairo + ``` @constructor func constructor{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(_name: felt) { @@ -341,7 +341,7 @@ from starkware.cairo.common.bool import TRUE of the network. You create an external function using the `@external` decorator: - ```cairo + ``` @external func store_name{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(_name: felt){ @@ -355,7 +355,7 @@ from starkware.cairo.common.bool import TRUE + View functions: View functions do not modify the state of the blockchain. You can create a view function using the `@view` decorator. - ```cairo + ``` @view func get_name{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(_address: felt) -> (name: felt){ @@ -413,7 +413,7 @@ Here are the most common decorators you'll encounter in Cairo: you can in your contracts, as hints are not added to the bytecode, and thus do not count in the total number of execution steps. - ```cairo + ``` %{ # Python hint goes here %} @@ -423,7 +423,7 @@ Here are the most common decorators you'll encounter in Cairo: inherited by other functions calls that require them. Implicit arguments are passed in between curly bracelets, like you can see below: - ```cairo + ``` func store_name{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(_name: felt){ let (caller) = get_caller_address(); @@ -440,7 +440,7 @@ execution. This can be very useful for implementing checks and proper access control mechanisms. An example is preventing a user to call a function except user is `admin`. -```cairo +``` // imports from starkware.starknet.common.syscalls import get_caller_address @@ -463,7 +463,7 @@ Contract interfaces provide a means for one contract to invoke or call the external function of another contract. To create a contract interface, you use the `@contract_interface` keyword: -```cairo +``` @contract_interface namespace IENS { func store_name(_name: felt) { @@ -477,7 +477,7 @@ the `@contract_interface` keyword: Once a contract interface is specified, any contract can make calls to that contract passing in the contract address as the first parameter like this: -```cairo +``` IENS.store_name(contract_address, _name); ``` @@ -493,7 +493,7 @@ repeatedly. A good example to demonstrate this is writing a function for getting the nth fibonacci number: -```cairo +``` @external func fibonacci{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(n : felt) -> (result : felt){ @@ -539,7 +539,7 @@ program, or call a function that might change ap in an unknown way). Here is an example to demonstrate what I mean: -```cairo +``` @external func get_balance{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}() -> (res: felt) { @@ -564,7 +564,7 @@ In simple cases you can resolve revoked references by adding the keyword `alloc_locals` within function scopes. In more complex cases you might need to create a local variable to resolve it. -```cairo +``` // resolving the `double_balance` function: @external func double_balance{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, @@ -600,7 +600,7 @@ range_check_ptr}() -> (res: felt) { Below is a simple automated market maker contract example that implements most of what we just learnt! Re-write, deploy, have fun! -```cairo +``` %lang starknet from starkware.cairo.common.cairo_builtins import HashBuiltin |