Add an example of activating XIM

[Determinant]

This follows up and closes #195.

To make this example work, one should ensure he/she configures LC_CTYPE and XMODIFIERS correctly in environment. An example is LC_CTYPE=zh_CN.utf8 and XMODIFIERS='@im=fcitx' for fcitx-base IMEs.

[jwilm]

Looks good, but I think this raises the question though of whether XIM should just work out of the box without the user having to set locale manually. Could use more feedback on that aspect.

[jwilm]

Might be nice to have a comment that passing an empty string will cause the locale to be set from environment variables. Ditto for XSetLocaleModifiers.

[Determinant]

User usually don't have to set LC_CTYPE manually as long as they have a utf8 locale environment. But they probably need to set XMODIFIERS or the config in the relevant application. But yes, this is just the current scenario for Chinese IME. Feedbacks are welcomed.

[Determinant]

The build test failed due to missing x11-dl crate. But x11-dl is in deps, could anybody explain why? (BTW, it passed cargo test on my machine).

[quininer]

Because this only works on linux (x11) and does not work in macOS with Windows.
Maybe you can add a #![cfg(target_os = "linux")]?

[quininer]

I think work out of the box is good, SDL2 also do so.

[Determinant]

@quininer adding it at the beginning of the file does not help because it will create an empty file so test will fail on non-linux platform. Is there any way of preventing it from running the test? I'm new to Rust, so not familiar with such options.

[quininer]

Maybe you can create a new crate under examples/?

[tomaka]

I don't think an example should be added for such an obscure thing, especially considering that the example is both unsafe and platform-specific.
Closing. Feel free to reopen if you disagree.

[jwilm]

I don't think an example should be added for such an obscure thing

It may be obscure to you, but IME support is an often requested feature for CJK users. Suggesting that it's obscure seems disrespectful for those that rely on it.

especially considering that the example is both unsafe and platform-specific.

Those seem like reasons to open a new issue about having a safe, cross-platform API for achieving this and not a reason for closing a PR about XIM example.

[tomaka]

That's probably just ignorance by myself, as I thought this example was supposed to demonstrate some sort of way of overwriting the default key mapping. IME is supposed to work out of the box.

[Ralith]

It would be nice if it did, but it currently does not, and something along these lines is necessary. Unfortunately working out of the box would require calling libc::setlocale on startup, which is global and hence might have surprising interactions with unrelated code.