Console.readAll blocks until EOF

[mhonert]

The Console.readAll function blocks until the EOF character is entered (e.g. by pressing CTRL-D in a linux shell), so it is not that useful for a CLI application.

It would be great if there was a function which reads a whole line until a newline character is entered (e.g. Console.readLine).

For portability this should probably take different newline character sequences into account (e.g. CR+LF for Windows and only LF for Linux/macOS).

[jedisct1]

I'm not sure how to do that. WASI doesn't expose anything about the underlying environment, so we don't know what an end of line looks like.

[MaxGraey]

I guess it relate to this discussion: WebAssembly/WASI#162

[mhonert]

If we can assume that a newline always ends with LF regardless of the platform, then
a simple solution would perhaps be to skip any CR characters?
At least this is how I implemented it for now in my chess engine, which reads UCI protocol commands from STDIN.

But I do not know, whether there are any use cases where recognizing the CR character might be necessary.

[mhonert]

I had a look at the ReadLine implementation of Go and they simply skip the CR (\r) character as well, if it is followed by a LF (\n): bufio.go.

[jedisct1]

But then, we have a similar problem with the WriteLine() counterpart.

[mhonert]

It seems that Go always writes '\n', regardless of the platform. For console output this is probably fine, although I did not yet check what happens when stdout is redirected to a file in Windows.