Question

I started to put print-statements throughout my code. So as not to clutter up the output, I did something like:

dputs LEVEL, "string"

where LEVEL is 0 for errors, 1 for important .. 5 for verbose and is compared to DEBUG_LEVEL. Now my problem is, that in a statement like:

dputs 5, "#{big_class.inspect}"

the string is always evaluated, also if I set DEBUG_LEVEL to 1. And this evaluation can take a long time. My favourite solution would be something like:

dputs 5, '#{big_class.inspect}'

and then evaluate the string if desired. But I don’t manage to get the string in a form I can evaluate. So the only think I could come up with is:

dputs( 5 ){ "#{big_class.inspect}" }

but this looks just ugly. So how can I evaluate a ‘#{}’ string?

Answer 1

I don’t think you can dodge the ugly there. The interpolation happens before the call to dputs unless you put it inside a block, which postpones it until dputs evaluates it. I don’t know where dputs comes from, so I’m not sure what its semantics are, but my guess is the block would get you the lazy evaluation you want. Not pretty, but it does the job.