Is it bad to put operations inside #{these}? [closed]

Question

Like this:

puts "Today my ostrich laid #{@eggs_laid - @stillborn - @wolves_ate} valid eggs."

If this was literally the only place I'd be needing this specific calculation, is there any point in making a valid_eggs function?

Answer 1

It's not inherently bad. But if the expression is complex, it reduces readability of the code. Here, I put the two snippets here, which one reads better?

puts "Today my ostrich laid #{@eggs_laid - @stillborn - @wolves_ate} valid eggs."

valid_eggs = @eggs_laid - @stillborn - @wolves_ate
puts "Today my ostrich laid #{valid_eggs} valid eggs."

Answer 2

This is an opinion piece: yes and no.

If it's "complex"¹ it likely belongs somewhere else.

If it's "simple"² it's not an issue.

It all comes down to readability, maintainability, appropriate re-use, and not doing anything silly.

---

^{1. For varying values of "complex". 2. For varying values of "simple".}

Answer 3

Absolutely not. Putting code inside #{...} interpolators is a legitimate part of fun in Ruby. For readability, you might consider:

puts "Today my ostrich laid %s valid eggs." % ( @eggs_laid - @stillborn - @wolves_ate )

But note that % interpolation and #{...} interpolation are two different kinds of fun, which are not fully interchangeable.