[obijohn]

I'm just trying to do some standard console input/output stuff but I'm running into problems. (dmd v. 0.145 on Windows)

First, when I use any form of Stdout with a string literal:

[Carlos]

[obijohn]

[obijohn]

The more I test this, the more it seems like a mango.io.Stdin problem. Here's an example.

[kris]

Egad!

That's a bug. I'll fix it later today.

[kris]

I fixed a problem relating to that "unexpected end of input". The issue there is one of input formatting (although there was a bug also).

Some background: when using a Reader for input (such as Stdin), there's an expectation that the incoming data is in a format suitable for parsing; this makes them a bit more strict than, for example, a text Iterator or string parser. Stdin is a bit of a hybrid, since it has to deal with arbitrary user-input, rather than something akin to a structured data-record. Historically, Stdin would treat an "empty token" as an error -- you can cause this by hitting CR without preceeding it with a number (in your examples above).

What I've changed will now ignore empty tokens ~ if you just hit CR, the example program will now just wait for you to enter 'something'.

~~~~~~~~

The second part of the issue is related to how console input is treated. If you enter more than one token at a time (as you show in the above test run), then subsequent calls to stdin will eat whatever tokens are still available. Your example program will wait for more input only when all available token have been consumed.

Why does it do this? Well, if you were to 'pipe' a file into your example (instead of directly interacting with the console) then you'd perhaps be horrified if only one token was read from the file, and all others were then discarded.

Thus, working with the console treats it as though it were a token stream. If you need to ensure a new value is explicitly provided for each prompt, then you'd need to clear the input buffer before reading the next token. To do this, you could use Stdin.getBuffer.clear();

Does that make sense?

~~~~~~~~~~~~~

Note also that you could drop down a level, and use mango.io.Console instead. This will give you more direct control over the console functionality. It also avoids that issue with the ""c suffix when prompting a user with text (I should note that Stdout also has a print() method, which operates just like printf).

With respect to the console, Mango has a few different layers. From bottom to top:

mango.io.Console -- direct console IO
mango.io.Print -- printf like output attached to the console
mango.io.Stdout -- Writer style console output, with a print() method
mango.io.Stdin -- Reader style console input, with token parsing

When working with raw input from mango.io.Console, you might find the mango.text.QuoteIterator functionality useful for extracting tokens. Also, the various parse() methods in mango.convert might come in handy.

I'll check the changes in soon, and you'll be able to pick them up via SVN on dsource.org (you'll need to synchronize properly, since there's been some related changes recently).

[obijohn]

kris,
Thanks for your prompt (pun intended ) attention to this. Just to be sure we're on the same page, there are actually 3 issues I noticed. The first 2 you decribed: the "empty token" situation when hitting CR before any input, and entering more tokens than expected as in the last 2 sample sessions of my example program above. However, the other issue is that even when exactly the correct number of tokens have been entered, Stdin does not get cleared completely and subsequent calls result in empy tokens and an error, as in the first sample session to my example program above. I tried using Stdin.getBuffer.clear(), but that does not help.

Is this last issue also addressed in the changes you're making?

[kris]

[kris]

Sorry this is taking so long to get a patch applied ... I'm having a little trouble getting it to shape up the way I'd like it to be. Haven't forgotten about it!

[obijohn]

Thanks for keeping this in mind. Right now I'm having to do this kind of thing:

[kris]

Well, I finally got this fixed

Through a combination of distractions, work, relocating, and a variety of other excuses, this took months to rectify. My profuse apologies for that. Fixes are in the repository.