* move the opaque section to after struct, enum, union, and add
hyperlinks
* improve the introduction of the zig build system. don't link to the
wiki.
* update to the latest zig init-exe example code
* rename headers to avoid redundant words such as "zig"
* simplify example code
* std.log: still print error messages in ReleaseSmall builds.
- when start code gets an error code from main, it uses std.log.err
to report the error. this resulted in a test failure because
ReleaseSmall wasn't printing `error: TheErrorCode` when an error
was returned from main. But that seems like it should keep working.
So I changed the std.log defaults. I plan to follow this up with a
proposal to change the names of and reduce the quantity of the
log levels.
* warning emitted when using -femit-h when using stage1 backend; fatal
log message when using -femit-h with self-hosted backend (because the
feature is not yet available)
* fix double `test-cli` build steps in zig's build.zig
* update docgen to use new CLI
* translate-c uses `-x c` and generates a temporary basename with a
`.h` extension. Otherwise clang reports an error.
* --show-builtin implies -fno-emit-bin
* restore the compile error for using an extern "c" function without
putting -lc on the build line. we have to know about the libc
dependency up front.
* Fix ReleaseFast and ReleaseSmall getting swapped when passing the
value to the stage1 backend.
* correct the zig0 CLI usage text.
* update test harness code to the new CLI.
This commit edits the "Hello, World!" introduction. It introduces Error Union
Types. Also, it changes `outStream` to `writer` in the code example and description.
To introduce the Zig programming language, the "Hello, world!" code sample now has
documentation to explain some of the features shown in the code sample
and contains links to those features in the rest of the documentation.
Writing style goals:
* Balance writing style to keep beginner and experience programmers interested.
* Be concise: allow the rest of the documentation to clarify language features.
This is an edge case that isn't too uncommon but is rather confusing to try to deduce without documentation, since it feels like `else` is being overloaded in this scenario and there's no obvious 'correct' behavior here. This just adds a test demonstrating how Zig currently behaves in this scenario.
The language reference's Index is a list of the documentation's contents in
order of appearance. This commit renames "Index" to "Contents" as in table of
contents. It also renames the HTML/CSS identifiers from "index" to "toc".
