Raku Books / Creating a Compiler in Raku / Arrays and Hashes

Assigning to an array item

OK, now we can create an array and it’s time to fill its elements with some data:

data[0] = 10;
data[1] = 20;

The assignment rule can be updated similarly to how we did it with string indexing in the previous chapter with an optional integer index in square brackets:

rule assignment {
    <variable-name> [ '[' <integer> ']' ]? '=' <value>
}

In the corresponding action, the presence of the index indicates that we are working with an array, otherwise it is a scalar variable.

method assignment($/) {
    if $<integer> {
        %!var{~$<variable-name>}[+$<integer>] =
            $<value>.made;
    }
    else {
        %!var{~$<variable-name>} = $<value>.made;
    }
}

After you run the program with the above assignments, the data variable will keep two values in the storage:

Hash %!var = {:data($[10, 20])}

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