What are some examples of memoization in different programming languages?

What are some examples of memoization in different programming languages?

Memoization is an optimization technique used to speed up function calls by storing previously computed results. In Python, for example, you can use the functools.lru_cache decorator to easily implement memoization.

Can you show me a JavaScript example?

Sure! In JavaScript, you can create a memoized function like this:

function memoize(fn) {
    const cache = {};
    return function(...args) {
        const key = JSON.stringify(args);
        if (cache[key]) {
            return cache[key];
        }
        const result = fn(...args);
        cache[key] = result;
        return result;
    };
}

This function stores results in a cache object.

What about in Ruby?

In Ruby, you can use a similar approach with a hash to store results. Here's an example:

class Memoizer
    def initialize
        @cache = {}
    end

    def memoize(key, &block)
        @cache[key] ||= block.call
    end
end

You can then use this class to memoize any method.

Are there any built-in memoization features in languages?

Yes, some languages have built-in support for memoization. For instance, in Haskell, you can use lazy evaluation to achieve memoization automatically.