mock_contract.cairo

// Declare this file as a StarkNet contract.
%lang starknet

from starkware.cairo.common.cairo_builtins import HashBuiltin
from starkware.cairo.common.registers import get_fp_and_pc

@storage_var
func mapping(key) -> (value: felt) {
}

@storage_var
func mapping_length() -> (value: felt) {
}

@constructor
func constructor{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(
    array_len: felt, array: felt*
) {
    mapping_length.write(array_len);
    fill_mapping(array_len, array);
    return ();
}

func fill_mapping{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(
    array_len: felt, array: felt*
) -> () {
    if (array_len == 0) {
        return ();
    }
    alloc_locals;
    let fp_and_pc = get_fp_and_pc();
    tempvar __fp__ = fp_and_pc.fp_val;

    // This could be useful for debugging...
    mapping.write(array_len, [array]);
    tempvar array_len_ptr = &array_len;
    tempvar val = [array];
    %{
        from rich.pretty import pprint
        from rich.console import Console
        from starkware.starknet.public.abi import starknet_keccak
        from starkware.cairo.lang.vm.crypto import pedersen_hash
        console = Console(markup=False, highlight=False)

        print(f"Still {ids.array_len} values to save...") 
        print(f"Saving {ids.val} to the storage...")
        console.print("Hey big boy look at me".upper(), style="bold underline #FFA500")
        console.print("Now that you reached this why do you try exotic stuff ...?", style="bold #FFA500")
        console.print("We're gonna mess with the memory now so brace yourself ", style="bold #FFA500")
        console.print("Print the last filled memory cell with memory[ap-1]", style="bold green") # should print 1
        console.print("Pretty cool huh? Now we're going to access a pointer's value", style="bold #FFA500")
        console.print("try memory[memory[ap-2]]", style="bold green") # should print array_len
        console.print("now icing on the cake we're gonna inspect the storage", style="bold #FFA500")
        console.print("now try __storage.read(pedersen_hash(starknet_keccak(b'mapping'), 5))", style="bold green") # should print the value of the key 5
        console.print("You can also check what variable is available with pprint(locals()) pprint(globals())", style="bold green") # should print the value of the key 5

        breakpoint()
    %}
    fill_mapping(array_len - 1, array + 1);
    return ();
}

@view
func product_mapping{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}() -> (
    res: felt
) {
    let (length) = mapping_length.read();
    let (res) = product_mapping_internal(length);
    return (res,);
}

func product_mapping_internal{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(
    len: felt
) -> (res: felt) {
    if (len == 0) {
        let (res) = mapping.read(len);
        return (res,);
    }
    let (temp) = product_mapping_internal(len - 1);
    let (mapping_val) = mapping.read(len);
    let res = temp * mapping_val;
    return (res,);
}