Add %p modifier to fmt!

[jdm]

I grow tired of printing out unsafe pointer values with fmt!("0x%x", somePointer as uint). It would be nice to use fmt!("%p", somePointer) instead.

[minhnhdo]

Hi, I'd love to work on this one. I have found the files which contain the code pertaining to the issue (src/libstd/unstable/extfmt.rs, src/libsyntax/ext/fmt.rs). Could you tell me where the format string is parsed and where the types of the arguments are determined?

[jdm]

Judging by the let pieces = parse_fmt_string(fmt, parse_fmt_err); in fmt.rs, it looks like you probably want to add a TyPointer to parse_type (https://github.com/mozilla/rust/blob/master/src/libstd/unstable/extfmt.rs#L311) and then you can probably cargo-cult the way that TyHex is used.

[minhnhdo]

@jdm could you please tell me what the exclamation mark in the following declaration means?
type ErrorFn = @fn(&str) -> !;

[jdm]

http://static.rust-lang.org/doc/rust.html#diverging-functions

[minhnhdo]

@jdm since the code is merged into the main branch, could you close this issue?