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Comment by Too | Hacker News Reader

Since you are working with dynamic language, step 2 should include adding type annotations or whatever they are called in php. Specifying stricter types makes refactoring much easier.

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Agreed. Adding type annotations is already a huge refactor in itself though and pretty risky with PHP. Once you have that done life will be much easier.

For those unfamiliar with php, or its type annotations, why is adding type annotations a risky step? Do they become enforcing?

    function foo(string $bar) { ... }
    foo(1234) // kaboom?

Yeah pretty much. It's risky because type checking produces fatal errors that aren't always easy to trap properly. You don't realize how much a code base relies on PHPs type coercion until you add annotations and watch it blow up, in often subtle ways.

"Subtle" is the keyword here.

I think your code will work because 1234 can be converted to a string. I think the trouble starts once you pass around objects.

It actually doesn't according to http://sandbox.onlinephpfunctions.com/code/8804b49c23d620228..., though different PHP versions could produce different results.

This works with PHP 7

<?php //Enter your code here, enjoy!

function foo(string $bar) { return $bar . $bar; }

echo foo(1234);

Wait? You mean you get runtime errors? That's well...good in a way but as you say dangerous on old code.

To get the true benefits of typing you should also run a static type analyzer.

Are there any for PHP?

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