What is the equivalent of Ruby IO.eof?

[zw963]

Class: IO (Ruby 3.1.1)

Thanks.

[naqvis]

Crystal IO don’t have eof marker or method. So any read operation returning a count of zero (0) is considered as EOF.

[existXFx]

Although Crystal embraces some Ruby stuff, it is not a derivative of Ruby. It may not be necessary to expect it to always have equivalents to Ruby. I’m curious if Crystal’s way doesn’t solve the problem?

[zw963]

I’m curious if Crystal’s way doesn’t solve the problem?

I am trying porting a quite complicated gem into Crystal, so, for those exists feature, i have to find an equivalent usage.

[Blacksmoke16]

@zw963

i have to find an equivalent usage.

Related:

@straight-shoota

Transforming Ruby code to Crystal with a focus on equivalence to the Ruby implementation will inevitably result in bad software design and potentially buggy behaviour. Ruby and Crystal are similar in many ways, but there are also a lot of significant differences (for example in concurrency mechanisms).

IMO it’s a wast of time if you’re just trying to find equivalents for Ruby and you’ll get a sub-par result.
Try to solve the problem in Crystal instead. Use the tools you have in Crystal. The Ruby implementation can serve as inspiration, of course.
Make it about the problem you want to solve, not about translating one solution for the problem found in Ruby.

You need to find an equivalent way to implement the features of the gem in Crystal. In some cases it’s not going to be as simple as copy the Ruby code over and add types. I’m sure there’s a way to implement the core feature you’re wanting in Crystal, even if the underlying implementation is different from the Ruby version.

[zw963]

I found this, based on your’s anwser.

def read_byte : UInt8?

Reads a single byte from this IO. Returns nil if there is no more data to read.

io = IO::Memory.new “a”
io.read_byte # => 97
io.read_byte # => nil