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In JavaScript, I can go
const materials = [
'Hydrogen',
'Helium',
'Lithium',
'Beryllium'
];
console.log(materials.map(material => material.length));
// expected output: Array [8, 6, 7, 9]
I guess that raku has some chops in functional - and I wonder if someone can clarify the equivalent code (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions )
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Since arrow functions don't have their own arguments , you cannot simply replace them with an arrow function. However, ES2015 introduces an alternative to using arguments : the rest parameter. // old function sum() { let args = []. slice.
Arrow Functions Return Value by Default: hello = () => "Hello World!"; Try it Yourself »
Arrow functions introduce concise body syntax, or implicit return. This allows the omission of the curly brackets and the return keyword. Implicit return is useful for creating succinct one-line operations in map , filter , and other common array methods.
Arrow functions are anonymous functions (the functions without a name and not bound with an identifier). They don't return any value and can declare without the function keyword. Arrow functions cannot be used as the constructors. The context within the arrow functions is lexically or statically defined.
The most direct equivalent would be
my @materials = <Hydrogen Helium Lithium Beryllium>;
say @materials.map(-> $material { $material.chars });
but an arrow sub is more explicit than you need in this case, because
say @materials.map: *.chars;
would also be sufficient (method call on a "whatever star" returns a code block that calls that method on its argument), and
say @materials».chars;
would also work (hyper-application applied to the dot operator).
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